IFIP IN '95 CONFERENCE
Copenhagen 28.-31.8.1995
TUTORIAL ON INTELLIGENT NETWORKS
Olli Martikainen*, Juha Lipiäinen**,
Kim Molin***
*Telecom Finland, P.O. Box 106, FIN-00511 Helsinki, FinlandTel. +358 2040 3503, Fax.+358 2040 3251
**Nokia Telecommunications, P.O.Box 33, FIN-02601 Espoo, FinlandTel. +358 0 5116691, Fax. +358 0 5115595
***Lappeenranta University of Technology, Datacommunication Laboratory,P.O.Box 20, FIN-53851 Lappeenranta, FinlandTel. +358 53 624 3613, Fax. +358 53 624 3650
AbstractThe development of telecommunications technology and the need for more advanced services has createdprojects on standardization of international Intelligent Networks (IN). The standards of Intelligent Networksdefine IN in an abstract point of view, so it leaves the service providers the decisions on their ownimplementations. The first standard sets of IN are Bellcore’s AIN.0 and the CCITT’s Capability Set 1 (CS1).They define the basic services of IN, additional features such as rapid service introduction and a flexiblearchitecture that provides future expansion to further IN Capability Sets. The standardization organisations,such as CCITT and ETSI, work hard to help the service providers to implement their IN architecture in order tobe able to provide international IN services. This kind of architecture is better known as Global IntelligentNetwork architecture and it should be taken into consideration already in the early implementations of IN. Thispaper presents some history of telecommunications technology, an overview of IN and its services and someadditional discussion on the future broadband IN.
Contents
Abbreviations
1. PREFACE 1
2. INTRODUCTION 2
2.1 Early computers and telecommunications 2
2.2 Switching systems development 3
2.3 Turning-points in telecommunications 5
2.3.1 UMTS 6
2.3.2 MEDIA 6
3. COMPUTER CONTROLLED TELECOMMUNICATIONS 8
3.1 CCITT Signalling System No. 7 8
3.1.1 Network Services Part 8
3.1.2 User Part 9
3.1.3 Signalling network structure 9
3.2 Telecommunications Management Network 10
3.2.1 Functional architecture 11
3.2.2 Informational architecture 11
3.2.3 Physical architecture 12
3.3 Intelligent Network 12
3.3.1 The need for IN 12
3.3.2 Definition of Intelligent Network 13
3.4 Numbering and Services 14
4. INTELLIGENT NETWORK ARCHITECTURE 16
4.1 Overview of IN 16
4.1.1. Origins of IN 16
4.1.2. IN standardization 18
4.1.2.1 IN standards bodies 18
4.1.2.1.1 ETSI 18
4.1.2.1.2 CCITT 18
4.1.2.2 Phased standardization 19
4.1.2.3 Structure of CCITT IN standards 19
4.1.2.4 Capability Set 1 20
4.1.2.5 IN CS1 Services 21
4.2 IN Functional Requirements 21
4.2.1 Service Requirements 22
4.2.2. Network Requirements 24
4.3 IN Conceptual Model 26
4.3.1 Physical Plane 28
4.3.1.1 Physical Entities 28
4.3.1.1.1 SSP 29
4.3.1.1.2 NAP 29
4.3.1.1.3 SCP 29
4.3.1.1.4 AD 30
4.3.1.1.5 IP 30
4.3.1.1.6 SN 30
4.3.1.1.7 SSCP 30
4.3.1.1.8 SDP 31
4.3.1.1.9 SMP 31
4.3.1.1.10 SCEP 31
4.3.1.1.11 SMAP 31
4.3.1.2 Interfaces between PEs 31
4.3.1.2.1 SCP-SSP interface 32
4.3.1.2.2 AD-SSP interface 32
4.3.1.2.3 IP-SSP interface 32
4.3.1.2.4 SN-SSP interface 32
4.3.1.2.5 SCP-IP interface 32
4.3.1.2.6 AD-IP interface 32
4.3.1.2.7 SCP-SDP interface 32
4.3.1.2.8 User interfaces 33
4.3.2 Distributed Functional Plane 33
4.3.2.1 Definition of FEs 34
4.3.2.1.1 CCAF 34
4.3.2.1.2 CCF 34
4.3.2.1.3 SSF 35
4.3.2.1.4 SSF/CCF Model 35
4.3.2.1.4.1 BCSM 36
4.3.2.1.4.2 Originating BCSM for CS-1 37
4.3.2.1.5 SCF 39
4.3.2.1.6 SDF 40
4.3.2.1.7 SRF 40
4.3.2.1.8 SCEF 40
4.3.2.1.9 SMAF 40
4.3.2.1.10 SMF 40
4.3.2.1.11 SCF Model and its relations 41
4.3.2.2 Mapping FEs to PEs 41
4.3.3 Global Functional Plane 41
4.3.3.1 SIB 42
4.3.3.1.1 Call Instance Data 43
4.3.3.1.2 Service Support Data 43
4.3.3.1.3 The SIB structure 44
4.3.3.1.3.1 Queue SIB 44
4.3.3.2 Basic Call Process 46
4.3.3.3 Global Service Logic 46
4.3.3.4 Relating the GFP to the DFP 46
4.3.4 Service Plane 46
4.3.4.1 Service Features 47
4.3.4.2 Description of CS1 Service Features 48
4.3.4.3 IN service modelling 51
4.3.4.4 Credit Card Calling 52
4.3.4.5 Virtual Private Network 53
4.3.4.6 Universal Personal Telecommunications 54
4.4 The IN-structured network 54
4.4.1 SCE 54
4.4.2 The function of IN 55
4.4.3 IN Application Protocol 56
4.5 Personal Communications Services 57
4.6 Integration of TMN and IN 58
4.6.1 Comparison of IN planes to TMN planes 59
4.7 Globalizing the IN 60
4.8 Future IN Capability Sets 60
4.9 Current activities of IN 61
5. CHANGES IN BUSINESS 62
5.1 Technology and services 62
5.2 Liberalization, alliances and competition 63
5.3 IN services 64
5.3.1 Benefits of IN 64
5.3.2 Cost structure 65
5.3.2.1 Initial cost of IN 65
5.3.2.2 Operational costs of IN 66
5.3.2.3 Basic call production costs 66
5.3.3 Service portfolio 66
5.3.3.1 Operators capability of offering services 66
5.3.3.2 Sales of service portfolio 66
5.3.3.3 Service development time frames 67
5.4 Evolution of IN capabilities at Telecom Finland 67
5.4.1 Pre-IN 67
5.4.2 Centralized IN 67
5.4.3 Special services 67
5.5 Distribution channels 67
5.6 Changes in enterprises 68
6. BROADBAND INTELLIGENCE AND MEDIA 70
6.1 Broadband networks 70
6.1.1 B-ISDN 70
6.1.1.1 Physical layer 70
6.1.1.2 ATM layer 71
6.1.1.3 ATM Adaption Layer 71
6.1.1.3.1 CBR 72
6.1.1.3.2 VBR 72
6.1.1.3.3 SEAL 72
6.1.1.4 Control plane 72
6.1.1.5 Management of the B-ISDN architecture 72
6.1.2 ATM networks 72
6.1.2.1 Virtual Channelss and Virtual Paths 73
6.2 Applications for the broadband networks 74
7. BROADBAND IN 76
7.1 Introduction 76
7.2 Telecom Finland BIN Project 76
7.3 BIN Architecture 77
7.3.1 Components 77
7.4 BIN and IN 77
7.5 Broadband services categorizing 78
7.6 Functioning of BIN architecture 78
7.6.1 Requirements of ATM network 79
7.7 Course of BIN events 79
7.7.1 Service request phase 79
7.7.2 Service activation phase 80
7.7.3 Service usage phase 80
7.7.4 Service after-usage phase 80
7.8 BINAP 80
7.8.1 BINAP-messages 80
7.8.2 User identification 81
7.9 CUSTOMER SERVICE PALETTE 81
7.9.1 BIN conceptual model 81
7.10 BIN MIB 82
7.11 TMN and BIN 83
7.12 The hardware configuration 83
7.13 Proposed services 84
8. REFERENCES 85
ABBREVIATIONS
AAB Automatic Alternative Billing
ABD Abbreviated Dialling
AC Application Context
ACB Automatic Call Back
ACC Account Card Calling
AD Adjunct
AOD Audio On Demand
AP Application Process
ASE Application Service Element
ASN.1 Abstract Syntax Notation One
ATM Asynchronous Transfer Mode
ATT Attendant
AUC Authentication Center
AUTC Authentication
AUTZ Authorization Code
B-IN Broadband IN
B-ISDN Broadband Integrated Services Digital Network
B-OSF Business OSF
B-SCP Broadband Service Control Point
B-SMS Broadband Service Management System
B-SSP Broadband Service Switching Point
BAF Basic Access Function
BCP Basic Call Process
BER Basic Encoding Rules
BRI Basic Rate Interface
BSF Base Station Function
BTF Basic Transit Function
CBR Continuous Bit Rate
CCAF Call Control Agent Function
CCBS Completion of Call to Busy Subscriber
CCC Credit Card Calling
CCF Call Control Function
CCITT Concultative Committee for International Telephony and Telegraphy
CCS Common Channel Signalling
CCSN Common Channel Signalling Network
CD Call Distribution
CD Compact Disk
CD-ROM Compact Disk-Read Only Memory
CF Call Forwarding
CFC Call Forwarding on BY/DA
CHA Call Hold with Announcement
CID Call Instance Data
CIDFP CID Field Pointer
CLI Calling Line Identity
COC Consultation Calling
CON Conference Calling
CPM Customer Profile Management
CRA Customized Recorded Announcement
CRD Call Rerouting Distribution
CRG Customized Ringing
CS Capability Set
CS1 Capability Set 1
CT2 Cordless Telephone 2
CUG Closed User Group
CW Call Waiting
DC Detection Capability
DCP Destination Point Code
DCR Destination Call Routing
DDD Direct Distance Dialing
DECT Digital European Cordless Telecommunications
DFP Distributed Functional Plane
DTMF Dual Tone Multi-Frequencies
DUP Destinating User Prompter
EC European Community
EF Elementary Function
EIR Equipment Identification Register
ERMES European Radio Message System
ETSI European Telecommunications Standards Institute
FC Functional Component
FE Functional Entity
FEA Functional Entity Action
FIE Facility Information Element
FMD Follow-Me-Diversion
FPH Freephone
GAP Call Gapping
GFP Global Functional Plane
GNS Green Number Service
GSL Global Service Logic
GSM Global System for Mobile communications
Groupe Special Mobile
GUI Graphical User Interface
GUS Gravis UltraSound
HDTV High Definition TeleVision
HLR Home Location Register
HP Hewlett Packard
IN Intelligent Network
INA Intelligent Network Architecture
INAP IN Application Protocol
INCM Intelligent Network Conceptual Model
IP Intelligent Peripheral
ISDN Integrated Services Digital Network
ITU International Telecommunications Union
IVS INRIA Videonconferencing System
LIM Call Limiter
LOG Call Logging
MACF Multiple Association Control Function
MAP Mobile Application Part
MAS Mass Calling
MCI Malicious Call Identification
MIB Management Information Base
MIT Management Information Tree
MMC Meet-Me-Conference
MPEG Moving Pictures Experts Group
MSC Mobile Services Center
MSCF Mobile Switching Center Function
MTP Message Transfer Part
MWC Multi-Way Calling
N-OSF Network OSF
N_ID Network ID
NAF Network Access Function
Ne-OSF Network element OSF
NEF Network Element Function
NNI Network-to-Node Interface
NSP Network Services Part
O-O Object-Oriented
OAM Operations And Maintenance
OC-x Optical Carrier level at x
OCS Originating Call Screening
ODR Origin Dependent Routing
OFA Off Net Access
OMAP Operations, Maintenance, and Administration Part
ONC Off Net Calling
ONE One Number
OSF Operations Systems Function
OSI Open Systems Interconnection
OSIRM OSI Reference Model
OUP Originating User Prompter
PABX Private Access Branch eXchange
PCM Pulse Code Modulation
PCS Personal Communications Services
PDH Plesiochronous Digital Hierarchy
PE Physical Entity
PIN Personal Identification Number
PLMN Public Land Mobile Network
PN Personal Numbering
PNP Private Numbering Plan
POI Point Of Initiation
POR Point Of Return
PRI Primary Rate Interface
PRM Premium Rate
PRMC Premium Charging
PSTN Public Switched Telecommunications Network
PTN Personal Telecommunications Number
PVC Permanent Virtual Channel
QOS Quality of Service
QUE Call Queueing
RACE Research and technology development in Advanced Communications technologies in Europe
RBOC Regional Bell Operating Company
REVC Reverse Charging
rN relationship N
ROSE Remote Operations Service Element
RTP Real-time Transport Protocol
S-OSF Service OSF
S_ID Service ID
SACF Single Association Control Function
SAO Single Association Object
SCCP Signalling Connection Control Part
SCE Service Creation Environment
SCEF Service Creation Environment Function
SCF Service Control Function
SCF Selective Call Forward on Busy/Don’t Answer
SCP Service Control Point
SDF Service Data Function
SDH Synchronous Digital Hierarchy
SEAL Simple and Efficient Adaptation Layer
SEC Security Screening
SF Service Feature
SIB Service-Independent building Block
SIG Special Interest Group
SLP Service Logic Program
SMS Service Management System
SP Service Plane
SPC Stored Program Control
SPL Split Charging
SRF Specialized Resource Function
SS Service Subscriber
SS7 Signalling System no. 7
SSD Service Support Data
SSF Service Switching Function
SSN Subsystem Number
SSP Service Switching Point
STM Synchronous Transport Module
STP Signalling Transfer Point
SVC Switched Virtual Channel
TCAP Transaction Capabilities Application Part
TCP Transmission Control Protocol
TCS Terminating Call Screening
TDR Time Dependent Routing
Telco Telecommunications Operating Company
TINA TMN+IN
TMN Telecommunications Management Network
TP Transact Processing system
TRA Call Transfer
U_ID User ID
UAN Universal Access Number
UDP User Datagram Protocol
UDR User-Define Routing
UMTS Universal Mobile Telecommunications System
UNI User-to-Network Interface
UP User Part
UPT Universal Personal Telecommunications
VBR Variable Bit Rate
VC Virtual Channel
VCC Virtual Channel Connection
VCI Virtual Channel Identifier
VLR Visitor Location Register
VOD Video On Demand
VOT Televoting
VP Virtual Path
VPI Virtual Path Identifier
VPN Virtual Private Network
WSF Work Station Function
Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 1
1. Preface
This Tutorial on Intelligent Networks has been prepared
for the IFIP IN '95 conference in Copenhagen. The first
version of this tutorial appeared in the second Winter
School on Telecommunications in Helsinki, March 1994,
and was then considerably improved for the IFIP TC-6
Workshop on Intelligent Networks in Lappeenranta on
August 1994 and later for SEACOMM'94 in Kuala
Lumpur, Malaysia. After that some corrections and
modifications have been added, and the authors express
their sincere gratitude for all the help they have obtained.
The tutorial has been written in co-operation with
Lappeenranta University of Technology and Telecom
Finland, but at present the second author is working with
Nokia Telecommunications.
The tutorial considers Intelligent Networks (IN) from
user, operator and application points of view. It gives
some history of the development of computers and
telecommunications networks towards more advanced
systems and networks that provide additional features, for
example, to the normal telephony services. These
computer controlled telecommunications networks and
architectures that add value to conventional
telecommunications networks are often referred to as
Intelligent Networks. This tutorial provides a presentation
of IN concepts, standards and technologies and gives a
description of the situation today. Also some influential
changes in the area of telecommunications business is
considered. Scenarios of future developments of IN are
provided. The authors of this tutorial are responsible for
the possible errors and mistakes in the text and all critics
and improvements are welcome.
Section 2. describes the history of telecommunications
and its development towards the future techniques. The
changes in the switching systems and some turning-points
in telecommunications are the main concern. The concept
of Computer Controlled Telecommunications is described
in section 3. It also includes signalling network history
and development, management networks for
telecommunications networks, and the need for more
advanced services. The Intelligent Network Architecture
(INA) is presented in section 4. from an abstract point of
view. Also some future plans to expand the architecture
are studied, such as Telecommunications Management
Network and Intelligent Network integration. In section
5. the effects of telecommunications networks
development to the telecommunications business are
studied. Some additional discussion of broadband
networks and possible broadband services in Intelligent
Networks is provided in section 6.
References are given in the text for further reading. For
this reason the references given are not always the
original ones.
This tutorial has been given a permission by the authors
to be used freely in noncommercial educational purposes.
Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 2
2. Introduction
2.1 Early computers and telecommunications
It is almost fifty years ago since intelligence first was
introduced in the concept of programmable electronic
calculators. Since then, the development of these
machines towards computers has been rapid. In 1950’s
computers acted as cenralized ‘batch’ processors and
there were no computer networks because of the
insufficient network technology. The programming of
early computers was very difficult because of low level
instructions and primitive user interfaces. However, first
high level languages such as Fortran were introduced
already in 1950's. The batch processor computers worked
in a simple way. They read the paper tapes bit by bit
containing information presented as holes in the paper. So
the Input/Output (I/O) operations of the computers were
far too inefficient to use the analogous
telecommunications network that was provided at that
time. The computers in those days were mainly used to
scientifical calculations that needed no other I/O
operations than instruction and data read, and a printout
function of the calculations. So, early computers were
completely in local use.
The next generation of computer technology followed
from the development of time sharing operating systems
in 1960's. Time sharing made it possible to have multiple
I/O-terminals connected to the computer, which was the
origin of local terminal networks with
datacommunnication protocols. At the same time the use
of computers was started in the process industry, where
computers removed process measurement and control
tasks from humans in the 1960’s. This meant that the I/O
operations of the computers had to be developed further
and they could already communicate with other
instrumentation devices. Later on, the process industry
became heavily computer controlled, and the computer
control of manufacturing was extended largely later in the
1970's. It was also then when the extensive use of
telecommunications networks became possible. This was
supported by digital PCM-transmission technology
(PDH-systems) deployed in the 1960´s and 1970's and
modems with signalling rates of about 300 bauds. In
those days, the telecommunications networks were still
largely non-digital and did not provide bit errorfree data
transfer. Bit errors appeared very often and for this reason
transport protocols at end systems and heavy link and
network protocols between the network nodes were
developed to minimize this unreliability problem.
Figure -1. Transaction processing system.
In 1970’s Transaction Processing systems (TP) were
taken in use in the area of banking. These TP’s
centralized servers located in the main office. The clients
sended requests via the communication network and the
TP answered them with low delay responses. Terminal
networks developed to local area networks (LANs) in the
1980's and packet switched data networks (X.25) were
introduced in late 1970's (Figure ). TP’s with
communication networks was a remarkable development
step and this client-server model is still in use in banking.
At day time, these computer systems work as transaction
processors, but at night they are used in batch processing.
This is because of the daytime heavy load of transaction
requests (even hundreds of thousands of requests per
hour) that arrive from several offices simultaneously.
Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 3
The batch functions are for example realizations of the
money transfer requests such as payment of salaries every
month ar any account transfers. These computer systems
need to serve the realtime queries and give responses to
thousands of locations worldwide.
2.2 Switching systems development
From 1870’s to 1950’s, the primary focus of swithing
system development was on producing better
technologies for permitting two people to engage in voice
communications over larger and larger distances and to
make this technology more readily available, cheaper, and
more reliable. During this period the industry moved
from local calls being handled by operators with plug
boards, to step-by-step switches, to panel switches, to
crossbar switches and to Stored Program Controlled
(SPC) switches. It is interesting to remember that in 1925
one of the most significant breakthroughs was the
separation of the connection control activities from the
maintenance of the actual connections during an active
call. This change, over time, allowed the switching
systems to reuse the more complex resources of the
switch (those used for initiating and setting up a call),
thus ending an era of having to duplicate these costly
resources and having them tied up for the entire duration
of a call. One of the major implications of switching
systems development during this period was that almost
all the information about how connections were to be
created resided on the individual switches, specifically,
subscriber data, information about how to provide the
limited functions available at that time, and implicit
network information were all contained in each switch
Benne93.
In the 1950’s, Direct Distance Dialing (DDD) began to be
deployed as a new service, but this was still a
continuation of the general focus to provide
telecommunications connections between two fixed
points. Furthermore, the long development time frames
and the then-available technologies favored producing
this new service by slightly rearranging the internal
structure of the switching systems and “squeezing in” the
new capability. The end result was that DDD increased
considerable network-related data in the local switches
and also added new functions related to the network
connection capabilities into the local switches. On many
of the existing switches, this involved adding specialized
“boxes” to correctly interpret the new dialed numbers and
route them to the correct places for proper DDD
connectivity.
To get some idea of the development of technology
associated with the interconnection aspects of the
telecommunications at that time, we can look at one of
the services we consider basic today. In 1956, the first
undersea cable using repeaters was activated at a cost of
about $6 million/circuit resulting in a cost of about
$75/minute. By 1976, the cost per circuit was reduced by
a hundredfold, thus permitting later developments to
focus more on providing various services beyond
connection. One of the driving forces for more complex
services at this time was the reduction in the cost of the
basic connections so that groups of customers with
specialized needs came to the market asking for
capabilities beyond simple connectivity. This was the
beginning of the transition period in which the structure
of the telecommunications industry was changing away
from the former connection focus toward a new service
focus. However, the pace of change was slow given the
technological problems that still had to be overcome to
provide fast and economical connections with high
quality. Thus, there was no driving need to reorganize
the basic structure of what existed; nor was there any real
guidance as to what kinds of services the customers
would be willing to purchase as a service marketing was
in its infancy Benne93.
Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 4
During the 1960’s and 1970’s, the requests for additional
services began to grow, but the pace was rather slow by
today’s standards since the technology to support these
new services was not readily available on the general
market. Since the new SPC-exhanges were able to swith
64 kbps connections transmitted over digital PDH
systems, it was a natural idea to propose this capability as
a basis for data communications. This was the birth of
the ISDN-concept (Integrated Services Digital Network)
where two digital 64 kbps data channels and one digital
16 kbps signalling channel was provided to the
customers. ISDN was an important concept since the
current service-driven thinking was created during its
development. For example, the other 64 kbps channel
could be used for speech and the other for data
transmission simultaneously. The whole capacity of 128
kbps could also be used for a reasonably high quality
compressed real time video connections. The availability
of ISDN growed, however, much slower than was
expected. The reasons for this were the existing large
installation base of analogous switching and transmission
systems incapable to support digital channels. Once
again, it was more economical and easier to “squeeze” the
new capabilities into the existing switching systems than
to change the switches and have to replace the embedded
base with newer technologies. This slow evolution
process was aided by the small market base for the newer
services.
For example, the office automation technologies available
were not very advanced and did not produce digital data
storage and transfer. Also, the derivative technologies
associated with the growth of computers, personal
computers, and microchip technology had not reached a
state where they were demanding telecommunication
services much beyond classical interconnectivity services.
During this period, the efforts to put more and more new
service capabilities onto the switching systems resulted in
a large expansion of the types of information being placed
on the switches, e.g., variations of call models, more
network-related information was brought into the
switches, and data under the control of the end users was
moved onto the switches (speed calling lists, centrex data,
etc.). As this data was moved onto the switches, the
programs to manipulate the data and ensure its integrity
also had to be installed in the switches. This resulted in
the switches becoming also very general data control and
usage systems Benne93.
As we entered the 1980’s, the advanced computer
technology started to penetrate from industrial and office
use also to low end products. Computer technology
became as an embedded technology in customer
equipments such as faxes and portable phones, and as a
control technology for the management and intelligent
control of networks. The computer technology
breakthrough was facilitated by the introduction of open
computer platforms (UNIX and Personal Computers,
PCs), the fast reduction of cost in computing and the
networking of PCs, minicomputers and mainframes. The
PCs provided a general platform for digital customer
premises equipments, capable to communicate via Local
Area Networks and Public Networks. This, in conjunction
with the lowering of transmission and interconnection
service costs, resulted in an exponential growth in the
demand for newer and more flexible telecommunications
services. Another major factor driving toward more
specialized services was the liberalization and
competition in telecommunications business. In the
United States the operator competition started with the
breakup of the Bell System and resulting competition,
where services were the factor that differentiated one
carrier form another. Furthermore, with diversiture, the
former local operating companies were permitted to make
instructions into one anothers’ traditional service areas
and, to do this effectively, they needed to have something
to offer that was not available from the local service
Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 5
provider. All of these changes resulted in customers being
more aware of what technology provided and demanding
that the telecommunications industry should meet the
new requirements for services Benne93.
The 1990’s and beyond will demand that the
telecommunications industry change its basic ideas about
the structure of their networks and how they will evolve.
Up until the 1980’s, network development was driven by
the need to provide cheap and efficient interconnections
between two fixed points. There was only minor
emphasis on structuring the switching systems to be
readily adaptable to the rapidly changing service
requirements that have appeared in the last decade. Now
that cheap, efficient interconnection capabilities are
available, the relative roles of the interconnection
capabilities and end-user services will be interchanged.
The demand for more and more customer based services
will continue to grow, and there will be an inceasing
demand for having the new services in shorter and shorter
time frames. Thus, the basic structure for the network,
and especially the structure and function of the switching
systems, will change to accomodate this need for rapid
deployment of more and more custom oriented services.
In summary, the telecomunications industry, which has
been interconnection-driven, will, in the future, be
service-driven. In this tutorial we shall discuss these
modern trends more thoroughly..
2.3 Turning-points in telecommunications
Several turning-points can be found in the history of
telecommunications technology (marked as circles in the
figure 2) .
Time1950 1960 1970 1980 1990 2000
Batchprocessors
Analogoustelephonyservice
IN
Broadband IN
ISDN
UMTS
B-ISDN
SS7
ATM
Packetdata networks
Modemservices
'Real'computers
PC
Corporationnetworks
NMT
GSM
MEDIA
MBS
Figure -2. The development of telecommunications.
First, the beginning of data transfer by the use of
analogous telephony service was an important stage in the
history. This service was not good for use in corporations
because of its low data transfer speed. Then, there was a
need for a data transfer service that used billing by data
amount while the expences of the analogous telephony
service consisted mainly of the data transfer time. The
packet switched data networks were developed especially
for corporations use. Second, CCITT (Consultative
Committee for International Telephone and Telegraphy)
introduced its seven layer OSI protocol stack SS7 to
replace the analogous signalling system. This was the
corner-stone for the digital telecommunications
technology that is used, for instance, in ISDN (Integrated
Services Digital Network). In the late 1980’s radio
signalling technology was advanced enough to provide
digital telephony service. The GSM (Global System for
Mobile communications) mobile phone technology,
introduced ito use n 1991, is also suitable for low-speed
data transfer. The Intelligent Network is an architecture
capable to integrate all the telecommunications services
mentioned in a flexible way.
The telecommunications networks and wide area
networks used PDH (Plesiochronous Digital Hierarchy)
technology in the physical data transfer. At the
Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 6
introduction of CCITT’s SDH (Synchronous Digital
Hierarchy) technology the physical data transfer rates
increased remarkably. A new technology, ATM
(Asynchronous Transfer Mode), was introduced to use the
available bandwidth efficiently in the 1992. By the
introduction of ATM it was possible to imagine of such
concepts as B-ISDN (Broadband Integrated Services
Digital Network ), broadband mobility and broadband IN.
These technologies will be discussed more accurately
later on. Broadband infrastructure will make it possible
to introduce advanced value added, mobile and media
services (Figure 2-3).
Figure 2-3. Turnover Value of Service Types
2.3.1 UMTS
UMTS (Universal Mobile Telecommunications System ) is
intended to be an international standard for global
telecommunication system. It is a third generation mobile
telecommunications system which integrates several
second generation mobile systems like cordless
telephones (CT2 (Cordless Telephone 2) and DECT
(Digital European Cordless Telecommunications)),
mobile telecommunications systems (GSM and PCN) and
radio message systems (ERMES (European Radio
Message System)) Hara93 (Figure 2-4).
Figure 2-4. Evolution of mobile services and systems.
In the next five years the third generation mobile
networks will be developed called the UMTS (Universal
Mobile Telecommunications System). UMTS was
researched in the RACE program of EC (European
Community) and ETSI’s group SGM5, which research
will be continued in the ACTS program of EC. This new
generation is based on application and service oriented
technology that supports on-demand transmission
capacity up to 2 Mbps in various radio environments.
The ultimate goal is to provide seamless end-to-end
services to the user by using a combination of fixed and
wireless/mobile access tecnologies, where a mobile phone
could be used at home, office and elsewhere.
UMTS is an open system which is based on TMN and IN
concepts. The system supports ISDN services and could
be at some degree compatible with B-ISDN with ATM-
switching and possible broadband mobile access. This
system is a very advanced telecommunications system
that supports global mobility and Intelligent Network
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services and is not expected to be introduced before the
year 2000.
There has also been proposals for still higher speed
mobile networks such as MBS (Mobile Broadband
System), which could support bit rates up to 34 Mbps.
However, the architectures of these proposed networks
are still open, and they will depend heavily on how the
control of mobility and intelligence will be distributed
over the network.
2.3.2 MEDIA
With media concept we understand here both radio,
television and cinema, and press and publishing
industries. All these will be available in electronic digital
forms either as stored media or interactively from the
distribution network.
In modern telecommunications the emerging competitive
media services market and the new technological
breakthroughs will bring remarkable changes. The
market changes are due to the integration of
telecommunications and information technology, which
brings interactive real time video and multimedia services
available to users. Examples of these services are digital
interactive TV, video on demand services for banking,
shopping and leasure, electronic press and publishing.
The technological requirements for these services are cost
effective broadband transmission and access
technologies, flexible computer based management and
control of services and networks, switching and service
applications and the support of mobility.
In technology substantial new breakthroughs are going
on. The introduction of cellular radio networks and
mobility is probably the most influential one in the next
few years. The broadband transmission and switching
technology is also maturing and will provide a cost
effective platform for service provision. When the
broadband customer access will be available, interactive
business and consumer services based on video and
multimedia will become possible. Common to all these
developments will be the computer controlled structure of
modern telecommunications, where protocols, application
technology and resource management are key factors.
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3. Computer ControlledTelecommunications
3.1 CCITT Signalling System No. 7
The word ‘signalling’ ment the transfer of analogous
signals in a network, for example in the analogous
telephony network the activation of nonintelligent
switches, just a few decades ago. In the context of
modern telecommunications, signalling can be defined as
the system that enables Stored Program Control
exchanges, network databases, and other “intelligent”
nodes of the network to exchange messages related to call
setup, supervision, teardown (call/connection control
information) Modar90, information needed for
distributed application processing (inter-process
query/response, or user-to-user data) and network
management information.
Just a few decades ago (and even today), the
telecommunications networks used analogous signalling,
based on frequency tones, between network nodes. Some
key attributes of these signalling methods are that they are
inband (i.e. signalling information is conveyed over the
same channel that is used for speech) Modar90; call set-
up times are long (from about 10 to 20 s); limited
information can be transferred resulting, among other
things, in restrictive network routing capabilities.
With the introduction of electronic processors in
switching systems came the possibility of providing
Common Channel Signalling (CCS). This is an out-of-
band signalling method in which a common data channel
is used to convey signalling information related to a
number of trunks. Modar90 CCITT published this new
signalling protocol stack SS7 (Signalling System No. 7)
based on CCITT OSI (Open Systems Interconnection)
Reference Model (OSIRM) in 1980. SS7 is fully digital
and SS7 protocol stack corresponds to the seven layers of
the OSIRM and includes the Application Services and
User Parts (UP) (Figure ). The signalling network
structure component of SS7 is the Network Service Part
(NSP), and it consists of the Message Transfer Part
(MTP) and the Signalling Connection Control Part
(SCCP). The OSIRM layers 4 - 6 are provided by
Intermediate Service Part (ISP) and each User Part.
SS7 is quite an advanced protocol stack. It includes
capabilities for congestion control and overload control. It
also includes features for avoiding congestion by
alternative routing or capacity expansion when heavy
load is detected. With congestion is ment generally,
shortage of resources, which is caused by an excessive
amount of load, or a failure that reduces the installed
capacity of a network element. SS7 also includes
capabilities for sending congestion and overload
indications to the adjacent exchanges or traffic sources.
M3010
Application
Presentation
Session
Transport
Network
Data link
Physical
OSI Reference Model
OMAP ASEs
TCAP
SCCP
SS7 protocol stack
ISP
MTP Level 3
MTP Level 2
MTP Level 1
UP
Figure -1. SS7 protocol architecture.
3.1.1 Network Services Part
MTP consists of levels 1-3 of the SS7 protocol stack and
it provides a connectionless message transfer system that
enables signalling information to be transferred across the
network to its desired destination. Functions are included
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in MTP that allow system failures to occur in the network
without adversely affecting the transfer of signalling
information. So the overall purpose of MTP is to provide
a reliable transfer and delivery of signalling information
across the signalling network and to have the ability to
react and take necessary actions in response to system and
network failures to ensure that reliable transfer is
maintained. The first level of MTP presents the signalling
data link functions. A signalling data link functon is a
bidirectional transmission path for signalling, consisting
of two data channel operating together in opposite
directions at the same data rate. It fully complies with the
OSI’s definition of the physical layer. Level 2 of MTP
presents the signalling link functions. The signalling link
functions correspond to the OSI’s data link layer.
Together with a signalling data link, the signalling link
functions provide a signalling link for the reliable transfer
of signalling messages between two directly connected
signalling points. The third level of MTP presents the
signalling network functions. They correspond to the
lower half of the OSI’s network layer, and they provide
the functions and procedures for the transfer of messages
between signalling points, which are the nodes of the
signalling network. Modar90
SCCP provides additional functions to MTP for both
connectionless and connection-oriented network services.
SCCP enhances the services of the MTP to provide the
functional equivalent of OSI’s network layer. The
addressing capability of MTP is limited to delivering a
message to a node and using a four-bit service indicator
to distribute messages within the node. SCCP
supplements this capability by providing an addressing
capability that uses DPCs (Destination Point Code) plus
Subsystem Numbers (SSN). The SSN is local addressing
information used by SCCP to identify each of the SCCP
users at a node. Modar90
3.1.2 User Part
The User Part forms the most upper layer of the SS7
protocol stack that use the services provided by the lower
layers SCCP and MTP. User Part functions are ISDN-UP,
TCAP (Transaction Capabilities Application Part) and
OMAP (Operations, Maintenance, and Administration
Part). The ISDN-UP is not discussed in this paper. TCAP
refers to the set of protocols and functions used by a set
of widely distributed applications in a network to
communicate with each other. TCAP directly uses the
service of SCCP. Essentially, TCAP provides a set of
tools in a connectionless environment that can be used by
an application at a node to invoke execution of a
procedure at another node and exchange the results of
such invocation. As such, it includes protocols and
services to perform remote operations. It is closely related
to the OSI Remote Operations Service Element (ROSE).
The OMAP of the SS7 protocol stack provides the
applications protocols and procedures to monitor,
coordinate, and control all the network resource that make
communications based on SS7 possible. Modar90
3.1.3 Signalling network structure
Figure -2. CCITT SS7 network structure.
Signalling networks consist of signalling points and
signalling links connecting the signalling points together.
(Figure ) As alluded to earlier, a signalling point that
transfers messages from one signalling link to another at
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level 3 is said to be a STP (Signalling Transfer Point).
Signalling points that are STP’s can also provide
functions higher than level 3, such as SCCP and other
level 4 functions like ISDN-UP. When signalling point
has an STP capability and also provides level 4 functions
like ISDN-UP, it is commonly said to have an integrated
STP functionality. When the signalling point provides
only STP capability, or STP and SCCP capabilities, it is
commonly called a stand-alone STP. Signalling links,
STP’s (stand-alone and integrated), and signalling points
with level 4 protocol functionality can be combined in
many different ways to form a signalling network. The
SS7 Network Services Part protocol is specified
independent of the underlying signalling network
structure. However, to meet the stringent availability
requirements given below (e.g., signalling route set
unavailability is not exceeded ten minutes per year), it is
clear that any network structure must provide
redundancies for the signalling links, which have
unavailabilities measured in many hours per year. In most
cases the STP’s must also have backups. Modar90
The worldwide signalling network is intended to be
structured into two functionally independent levels: the
national and international levels. This allows numbering
plans network management of the international and the
different national network to be independent of one
another. A signalling point can be a national signalling
point, an international signalling point, or both. If it
serves both, it is identified by a specific signalling point
code in each of the signalling networks. Modar90
3.2 Telecommunications Management Network
Telecommunications Management Network (TMN) is a
generic, management-oriented architecture, intended to be
used for all kinds of management services. Appel93 It
has been defined in the CCITT M.3000 series standards.
According to the concept it intends to meet several
purposes: several network and devices, digital and
analogic transmission systems, circuit- and packet
switched data networks, public exchanges and PABX’s
(Private Access Branch Exchange).
TMN is intended to support different management based
areas. These five functional areas are:
Performance management
fault management
configuration management
accounting management
security management
The functionality of TMN consists of the following
subjects: Error! Reference source not found.
the ability to exchange management information
across the boundary between the telecommunications
environment and the TMN environment.
the ability to convert management information from
one format to another so that management
information flowing within the TMN environment
has a consistent nature
the ability to transfer management information
between locations within the TMN environment
the ability to analyse and react appropriately to
management information
the ability to manipulate management information
into a form which is useful and/or meaningful to the
management information user
the ability to deliver management information to the
management information user and to present it with
the appropriate representation
the abilty to ensure secure access to management
information by authorized management information
users
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In TMN architecture there are mainly three architectural
points of view each of which can be taken into account
when TMN network is designed. These aspects are:
fucntional, informational and physical architectures. Each
of them studies the network architecture from different
apects.
3.2.1 Functional architecture
The TMN functional architecture is described with
functional blocks such as the Network Element Function
(NEF), The Operations Systems Function (OSF) and
Work Station Function (WSF). (Figure ) NEFs model all
entities that form the network to be managed. NEFs are to
be located physically on network elements. OSF provide
the TMN functions for processing, storage and retrieval
of management information. They form the core part of
the TMN. Four different OSFs can be identified
according to a hierarchial partitioning into four layers: the
network element management layer, responsible for the
management of a subset of the network elements in the
whole network; the network management layer,
responsible for the technical provision of services
requested by the upper layer. This layer has an overall
view of the network. The service management layer is
responsible for all negotiations and resulting agreements
between a customer and the service offered to this
customer. The business management layer is responsible
for the total enterprise. Therefore, it is possible to identify
different types of OSFs; the NE-OSF, N-OSF, the S-OSF
and the B-OSF. WSF represent the functionalities and
information modelling entities related to the TMN man-
machine communications between the management
system and the human operator. Appel93
Between the function blocks NEFs, OSFs and WSFs
there are different kind of reference points: Q-, F- and X-
type. The Q-type reference point is between OSFs of
contiguous layers or between the OSF and the NEF; the
F-type reference point is between the WSF and the OSF;
and the X-type reference points are between OSFs
belonging to different domains.
Figure -3. TMN Operations Systems functional hierarchy.
Appel93
3.2.2 Informational architecture
TMN informational architecture is based on Object-
Oriented (O-O) point of view. Management systems
exchange information modelled in terms of managed
objects. Managed objects are conceptual views of the
resources that are being managed or may exist to support
certain management functions (e.g. event forwarding or
event logging). Thus, a managed object is the abstraction
of such a resource that represents its properties as seen by
(and for the purposes of) management. A managed object
may also represent a relationship between resources or a
combination of resources (e.g. a network). Error!
Reference source not found.
Management of a telecommunications environment is an
information processing application. Because the
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environment being manages is distributed, network
management is a disributed application. This involves the
exchange of management information between
management processes for the purpose of monitoring and
controlling the various physical and logical networking
resources (switching and trasmission resources). Error!
Reference source not found.
The TMN architecture is based on Manager/Agent
architecture. (Figure ) A manager takes care of the
distributed applications part that issues management
operation directives and receives notifications. The agent
role if the part of the application process that manages the
associated managed objects. The role of the agent will be
to respond to the directives issued by a manager. It will
also reflect to the manager a view of these objects and
emit notifications reflecting the behaviour of these
objects.
Figure -4. Interaction between Manager, Agent and
managed objects.
In TMN the manager uses polling method to get the
information from the agents. The agents store the
statictics information in their databases that are called
MIBs (Management Information Base). A MIB is a
conceptual database structure. It represents the set of
managed objects within a managed system. The structure
of the MIB is often showed in the form of a tree. This tree
is called a Management Information Tree ( MIT). (Figure -
5) The tree is organized in a hierarchical way. At the
upper parts of the tree resides the most meaning attributes
and they are specified more entirely with the lower layer
attributes.
Figure -5. Management Information Tree.
3.2.3 Physical architecture
NEFs identify all the network elements as physical
entities in TMN. Operations Systems (OS) form the core
part of every TMN domain. The TMN physical
architecture is not discussed more accurately in this
paper.
3.3 Intelligent Network
3.3.1 The need for IN
In the past few years the development of
telecommunications networks has been rapid. The
telecommunications network functions before were
controlled mainly by operators. The desire to share data
and distribute application processing among network
elements, the need for standard interfaces between them
Garra93 and user demands for more sophisticated
telecommunications services has changed the controlling
of network elements notably. The telecommunications
network elements today are controlled by the network
operator, the service provider or the customer himself.
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To integrate the control and management of different
services inside the operator, or to be able to provide third
party control and management services, control and
management interfaces with software support are needed.
The development of IN architecture was initiated by
Bellcore in USA almost ten years ago in order to help the
Regional Bell Operating Companies to become more
competitive in deregulated telecommunications
environment. The original goal was to provide network
operators with the ability to introduce, control and
manage services more effectively by using a centralized
database in a Service Control Point (SCP) for controlling
and managing the various network services. Lauta93
The objective of IN is to allow the inclusion of additional
capabilities to facilitate provisioning of service,
independent of the service or network implementation in
a multi-vendor environment. Service implementation
independence allows service providers to define their own
services independent of service specific developments by
equipment vendors [Q1201].
Network implementation independence allows network
and service operators to allocate functionality and
resources within their networks and to efficiently manage
their networks independent of network implementation
specific developments by equipment vendors.
The network architectures, so far, have developed almost
independently of each other. This point of view, of
course, causes the network operators and service
providers to provide independently implemented service
to customers. The basic idea of IN has been that it
facilitates the provisioning of services independently
from the telecommunications networks and equipment
vendors. So, the IN acts as a distributing and centralizing
framework of the telecommunications services. With this
framework, it is possible to introduce advanced customer
oriented services rapidly and cost effectively.
3.3.2 Definition of Intelligent Network
Intelligent Network (IN) is an architectural concept for
the operation and provision of new services which is
characterized by [Q1201]:
- extensive use of information processing techniques;
- efficient use of network resources;
- modularization and reusability of network functions;
- integrated service creations and implementation by means of
the modularized reusable network functions;
- flexible allocation of network functions to physical entities;
- portability of network functions among physical entities;
- standardized communication between network functions vie
service independent interfaces;
- service subscriber 1) control of some subscriber-specific
service attributes;
- service user 2) control of some user-specific service
attributes;
- standardized management of service logic.
IN is applicable to a wide variety of networks, including
but not limited to: public switched telephone network
(PSTN) mobile, packet switched public data network
(PSPDN) and integrated services digital network (ISDN)
- both narrowband-ISDN (N-ISDN) and broadband-ISDN
(B-ISDN).
IN supports a wide variety of services, including
supplementary services, and utilizes existing and future
bearer services (e.g. as those defined in N-ISDN and B-
ISDN contexts).
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3.4 Numbering and Services
The user identification has mainly been based on the
access points of the telecommunications network. The
users’ access points were separateded from each other
with the Network ID (N_ID). This N_ID was at the early
telecommunication systems the telephone number that did
not support any mobility at all. The introduction of
mobile services and third party media services will create
new needs for customer and service identification (Figure
3-6). In Figure 3-6 service identifications can contain
also other service related data than the service or program
identification itself.
Figure 3-6. Numbering Types
The ISDN supplementary services identifications consist
of the following identifiers [Q932]:
Service profile: Service profile refers to the information that the
network maintains for a given user to characterize the service offered
by the network to that user. As an example, this may contain the
association of feature identifiers to specific supplementary services. A
service profile may be allocated to an access interface or to a particular
user equipment or a group of user equipments.
SPID: The service profile identifier is a parameter carried in a service
profile identification information element that is sent from the user to
network to allow network assignment of a USID and TID. A user's
SPID should uniquely identify a specific profile of service
characteristics stored within the network. The SPID will allow the
network to distinguish between different terminals that would otherwise
be indistinguishable (e.g., same N_ID). The SPID value is provided to
the user at subscription time.
USID: User service identifier. A USID uniquely identifies a service
profile on an access interface.
TID: Terminal identifier. A TID value is unique within a given USID.
If two terminals on an interface subscribe to the same service profile,
then the two terminals will be assigned the same service USID.
However, two different TIDs are required to uniquely dentify each of
the two terminals.
EID: Endpoint identifier. The endpoint identifier information element
is used for terminal identification. The endpoint identifier parameters
contain a USID and TID and additional information used to interpret
them.
In OSI environment there are two naming conventions
that can be applied to services, the Object Identifier
specified in the ASN.1 notation [ISO 8824] and the
Distinguished Name specified in the Directory standard
[ISO9594]. The services can be considered as
Application Entity instances, whose names can be
presented using either Object Identifiers or Relative
Distinguished Names [ISO 7498-3]
There can be three main identification types depending on
the roles in the network: N_ID’s, S_ID’s (Service ID) and
U_ID’s (User ID) (Figure 3-7). S_ID defines the service
that is used by the user via the network. U_ID defines
the exact user irrespective of the network. The relation
between user and network ID’s in old telephone networks
is hence U_IDN_ID. The service identification is
dependent on these three types.
In the future there can exist several other relations too.
For example, the mobility of users and services. The user
can move from N_ID to another and use a service that
could be either distributed throughout the
telecommunications network or serve the user as a mobile
service. Also from different U_ID’s can be produced
groups where the telecommunications network is used as
a private network inside the whole telecommunications
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system. As a more advanced telecommunications system,
GSM uses for mobility the relation where each user with
U_ID is attached to a Base Station channel with invisible
N_ID. This relation is updated in roaming and handovers
that the GSM network manages. The Intelligent Network
differentiates the user, network and service from each
other. This description can manage mobility from each of
its components and even of different Intelligent Networks
when IN uses services from other networks.
Figure 3-7 Different relations between identifications.
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4. Intelligent Network Architecture
4.1 Overview of IN
The term Intelligent Networks (IN) is used to describe an
architectural concept which is intended to be applicable to
all telecommunications networks and aims to ease the
introduction and management of new services.
The objective of IN is to allow the inclusion of additional
capabilities to facilitate provisioning of service,
independent of the service or network implementation in
a multi-vendor environment. Service implementation
independence allows service providers to define their own
services independent of service specific developments by
equipment vendors [Q1201].
Network implementation independence allows network
and service operators to allocate functionality and
resources within their networks and to efficiently manage
their networks independent of network implementation
specific developments by equipment vendors.
4.1.1. Origins of IN
The Intelligent Networks is a telecommunications
network services control and management architecture.
In February 1985, Regional Bell Operating Companies
(RBOC) submitted a Request For Information (RFI) for a
Feature Node concept with the following objectives
Ambro89:
Support the rapid introduction of new
services in the network
Help establish equipment and interface
standards to give the RBOCs the widest
possible choice of vendor products
Create opportunities for non-RBOC service
vendors to offer services that stimulate
network usage
As with the past telecommunications technology, it was
not desirable to introduce short term services, because of
the long implementation and development period. Now,
with IN technology it is possible to introduce new
services rapidly without affecting the available services.
IN defines a large set of standards that describe the
interfaces between different network control points. With
only specifying the interfaces IN makes it possible for
vendor systems to provide with different products and ,of
course, for operators to use any of these products in their
network configuration. IN includes also capabilities for
other than operators to introduce new services into the
telecommunications network. This will change the
structure of the telecommunications business, which is
the main concern in the section 5 of this paper.
The IN’s main advantage is the ability to control
switching and service execution from a small set of
Intelligent Network nodes known as Service Control
Points (SCP). SCPs are connected to the network
switches (known as Service Switching Points) via a
standardized interface; CCITT Signalling System No. 7.
The SS7 will facilitate a multi-vendor SCP and SSP
marketplace, and the standardization of application
interfaces allows a multi-vendor software marketplace for
SCP applications (that is, the service control logic and its
related data) (Figure -1). The SSPs detect when the SCP
should handle a service. The SSP forwards a standardized
SS7 (TCAP) message containing relevant service
information. Via the TCAP message, the service control
logic in the SCP directs the SSPs to perform the
individual functions that collectively constitute the
service (such as connecting a subscriber number or an
announcement machine) Ambro89 .
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The IN’s long term goal is the ability to introduce new
services, or change existing services quickly, without
having to adapt SSP software (only parameters or trigger
updates). The adaptation will be confined to the SCP
where parameters or stimuli are updated. This goal was
first planned by Bellcore to be achieved in two stages:
IN/1 and IN/2 Ambro89 IN/1 definitions introduced the
term Intelligent Network in 1986 and in 1987 IN/2
definitions were introduced. In 1988 IN/2 was delayed
and IN/1+ was introduced instead. In 1989 Bellcore
abandoned IN/1+ for several reasons, some being
problems in the technology and lack of multivendor
involvement. Instead a MultiVendor Initiative (MVI)
was started in 1989 to define Advanced Intelligent
Network (AIN). At the same time CCITT and ETSI
started work on IN. The IN basic concepts for a service
dependent architecture were introduced already in IN/1.
The AIN concepts were essentially those of IN/2 defining
a fully service independent architecture with total
separation of service logic from the underlying seitching
system. These principles were accepted also by CCITT
and ETSI work. The AIN Release 1 and CCITT CS1
were published in 1993. Let us finally summarize early
IN/1 and IN/2 outlines.
IN/1 requires updates in the SSP and SCP in order to
support a new service. A typical IN/1 service is the
Green Number Service (GNS) with which a subscriber
can call a number free of charge. The SSPs contain
triggers (such as the value of the dialed digits) that tell
the SSP to send a message to an SCP in order to get
information about the destination to which the call
should be routed. Migration from IN/1 to IN/2 implies
significant changes in the SSPs to accomodate new
services.
Stage 1: IN/1
Once IN/2 is in place, no updates need be made to the
SSPs software when new services are introduced. The
IN/2 triggers advise the SSP whether to complete
execution locally. All SSPs and SCPs contain set of basic
service elements (for example, connect two lines,
disconnect a line). The SCP also contains service
relevant data. These basic service elements are knows as
Functional Components (FC) from which each service
can be contructed. A customer could conceptualize a new
service and the network operator, via the SMS/SCP,
could construct it quite rapidly. Any successful and
widely-used service may be downloaded (via the service
logic) to, but transparent to, the SSPs (if this is more
economic or provides a desired higher grade of service).
This facilitates complete rapid service creation. Rapid
service creation and user programmability will take place
in the SCP and the SMS.
Stage 2: IN/2
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Figure -1. Intelligent Network overview. Homa92
An Intelligent Network is able to separate the
specification, creation, and control of telephony services
from physical switching networks. The key benefit of this
capability is that exchange carriers will be able to rapidly
engineer new revenue-producing services, in response to
market opportunities, without having to rely on lenghty
cycles for implementing them entirely on switching
fabric. Ultimately, service creation, or at least service
customization, can be extended to subscribers Homa92.
The original IN concepts IN/1 and IN/2 were not
considered sufficient to support vendor independence
and open interfaces, and extensive standardization
activities were started in 1989's. The first available
publications were the Advanced Intelligent Network
(AIN), and after that CCITT and ETSI provided their
first draft recommendations. Our presentation here is
mainly based on the CCITT, presently ITU-T,
recommendations.
4.1.2. IN standardization
4.1.2.1 IN standards bodies
The IN standards are defined by ETSI and CCITT. Also,
in the USA, the work is being done by Bellcore, which is
not a standards body but provides the major input to the
American National Standards Institute committee TS.1.
Roger90
4.1.2.1.1ETSI
ETSI was created in 1988 and its members are the
European Telcos (Telecommunications Operating
Company), manufacturers, user representatives and
research bodies. ETSI has two purposes. IN belongs to
the latter category. Roger90
to achieve workable versions of international
standards for the European environment
to define European standards in areas where quick
response is required for technical development
4.1.2.1.2CCITT
Work on international standards for IN began at CCITT
in 1989. Study Group XI.4 is responsible of the
standardation. CCITT expects that the specification and
deployment of IN will continue over a number of study
periods. CCITT name has changed to ITU (International
Telecommunications Union) and there the Special Interest
Group (SIG) is T (ITU-T). Its approach to the
development of IN standards assumes that it is necessary
to start with a minimum set of criteria which are
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sufficiently open ended that they can evolve to meet the
needs of the long-term concept as this becomes a practical
reality. Roger90
Both ETSI and ANSI are keen to ensure that CCITT
recommendations agree substantially with their own
activities, and collaboration between all three bodies is
likely to be an important determinant in the rapid
development of realistic IN standards.
4.1.2.2 Phased standardization
To meet the goals and objectives, CCITT has embarked
on a phased standardation process toward the target IN
architecture (INA) [Q1201]. CCITT works on defining a
set of capabilities for each phase and simultaneously on
evolving the view of the target IN architecture called the
long-term capability set (LTCS) (Figure -2) The IN
subjects of standardization are called Capability Sets
(CS). The Capability Sets involve service creation,
management and interaction and also network
management, service processing and network
internetworking. These CS’s are backwards-compatible
to the previous CS’s so the standardation and
implementation of the services can be progressed through
a sequence of phases Garra93 .
Figure -2. Phased standardation of IN.
4.1.2.3 Structure of CCITT IN standards
The basic standard that defines the framework of other IN
standards is Q.1200 - Q-Series Intelligent Network
Recommendations Structure. The standards have been
numbered so that every new CSx will have a number that
begins with 12x and the description of the CSx
recommendation part y will be numbered also
systematically such as 12xy. (Table -1) So, the principles
introduction for IN CS2 will be recommendation number
Q.1221.
00 - General
10 - CS1 1 - Principles Introduction
20 - CS2 2 - Service Plane (not included forCS1)
30 - CS3 3 - Global Functional Plane
40 - CS4 4 - Distributed Functional Plane
50 - CS5 5 - Physical Plane
60 - CS6 6 - For future use
70 - CS7 7 - For future use
80 - CS8 8 - Interface Recommendations
90 -Vocabulary
9 - Intelligent Network Users Guide
Table -1. IN recommendations structure.
4.1.2.4 Capability Set 1
It has been an international and european wide aim to
define the first step of INA. These recommendations are
gathered into a set called IN Capability Set 1 (CS1).
There are two standardation organisations working on
CS1: CCITT and ETSI. CCITT has gathered these
recommendations into the Q.121y -series. (Table -2)
CCITT’s and ETSI’s standards do not substantially differ
from each other.
CCITT Study Group XI, Working Party XI/4 includes
representatives from most of the important
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telecommunications network operators and equipment
vendors in the world. Study Group XVIII also is involved
in the initial set of IN standards, and is sharing
responsibility for the Introductory Recommendations. At
these meetings, there is an obvious willingness to
strongly focus on achieving a realistic initial set of IN
capability, which is both technically implementable and
commercially deployable.Duran92
RecommendationQ.1200
Q-Series Intelligent NetworkRecommendations Structure
RecommendationQ.1201
Principles of Intelligent NetworkArchitecture
RecommendationQ.1202
Intelligent Network - ServicePlane Architecture
RecommendationQ.1203
Intelligent Network - GlobalFunctional Plane Architecture
RecommendationQ.1204
Intelligent Network - DistributedFunctional Plane Architecture
RecommendationQ.1205
Intelligent Network - PhysicalPlane Architecture
RecommendationQ.1208
Intelligent Network - ApplicationProtocol General Aspects
RecommendationQ.1211
Intelligent Network - Introductionto Intelligent Network CapabilitySet 1
RecommendationQ.1213
Intelligent Network - GlobalFunctional Plane for CS1
RecommendationQ.1214
Intelligent Network - DistributedFunctional Plane for CS1
RecommendationQ.1215
Intelligent Network - PhysicalPlane for CS1
RecommendationQ.1218
Intelligent Network - IntelligentNetwork Interface Specifications
RecommendationsQ.1219
Intelligent Network Users guidefor Capability Set 1
Table -2. IN CS1 recommendations.
In defining IN CS1, CCITT applied the INCM
(Intelligent Network Conceptual Model) using both
“bottom-up” and “top-down” approaches. The former
approach focused on modelling the capabilities of
existing networks in terms of functional and physical
architectures that could evolve the target IN architecture,
given CCITT’s objective of evolving IN from existing
networks. The latter approach was service-driven and it
focused on identifying a set of IN CS1 services and
Service Features. Then driving these down through the
INCM in order to identify the set of service-independent
capabilities for IN CS1, evolvable to the target set of IN
capabilities, and verify that this set could be supported by
the functional and physical architectures defined via the
“bottom-up” approach Garra93.
IN CS1 defines capabilities of direct use to both
manufactures and network operators in support of circuit-
switched voice/data services either defined or in the
process of being defined by CCITT. The primary
characteristic of the target set of IN CS1 services is that
they apply during the setup phase of a call or during the
release phase of a call. CCITT chose this single-ended
service characteristic to limit the operational,
implementation, and control complexity for IN CS1.
Even with this limitation, it may be expected that
equipment suppliers will support interworking of IN CS1
capabilities with existing switch-based services, including
more complex services such as those that apply during the
active phase of a call. For example, IN CS1 routing,
charging, and user interaction capabilities may be used to
customize or improve existing switch-based services to
better satisfy market needs. Garra93
It is anticipated that CS1 recommendations of CCITT and
ETSI will be adopted world-wide. This can help to
develop open interfaces between the SSP (Service
Switching Point) and SCP (Service Control Point), thus
putting into effect one of the important goals of the IN,
namely vendor independence. Lauta93
4.1.2.5 IN CS1 Services
Allthough, by nature, the IN is a service independent
architecture, it is relevant to describe the general CS-1
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service capabilities. The services and Service Features
that are to be supported by CS-1 are fundamental to the
CS-1 Service Building Blocks, call processing model and
service control principles.
The target set of CS-1 defines several services (Table -3)
and service features. A service is a stand-alone
commercial offering, characterized by one or more core
Service Features, and can be optionally enhanced by other
Service Features. A Service Feature is a specific aspect of
a service that can also be used in conjunction with other
services/Service Features as part of a commercial
offering. It is either a core part of a service or an optional
part offered as an enhancement to a service. Q1201 The
service composition and Service Features will be
discussed more precisely later on.
Automatic AlternativeBilling (ABB)
Mass Calling (MAS)
Abbreviated Dialling(ABD)
Malicious CallIdentification (MCI)
Account Card Calling(ACC)
Premium Rate (PRM)
Credit Card Calling(CCC)
Security Screening (SEC)
Call Distribution (CD) Selective Call Forward onBusy/Don’t Answer (SCF)
Call Forwarding (CF) Split Charging (SPL)
* Completion of Call toBusy Subsrciber (CCBS)
Televoting (VOT)
* Conference Calling(CON)
Terminating CallScreening (TCS)
Call ReroutingDistribution (CRD)
User-Defined Routing(UDR)
Destination Call Routing(DCR)
Universal Access Number(UAN)
Follow-Me-Diversion(FMD)
Universal PersonalTelecommunications
(UPT)
Freephone (FPH) Virtual Private Network(VPN)
Note: The service indicated with a * may only be partially
supported in CS1, because they require capabilities
beyond those of type A services.
Table -3. Target set of IN CS1 services.
4.2 IN Functional Requirements
IN functional requirements arise as a result of the need to
provide network capabilities for both customer needs
(service requirements) and network operator needs
(network requirements) [Q1201].
A service user is an entity external to the network that
users its services. A service is that which is offered by an
administration to its customers in order to satisfy a
telecommunications requirement. Part of the service used
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by customers may be provided/managed by other
customers of the network. These are often called as third
party services and their providers as 3rd party service
providers.
Service requirements will assist in identifying specific
services that are offered to the customer. These service
capabilities are also referred to as (telecommunication)
services: Network requirements span the ability to create,
deploy, operate and maintain network capabilities to
provide services.
Service and network requirements can be identified for
the following areas of service/network capabilities:
service creation, service management, network
management, service processing and network
interworking.
- Service creation: An activity whereby
supplementary services are brought into being through
specification phase, development phase and verification
phase.
- Service management: An activity to support the
proper operation of a service and the administration of
information relating to the user/customer and/or the
network operator, Service management can support the
following processes: service development, service
provisioning, service control, billing and service
monitoring.
- Network management: An activity to support
the proper operation of an IN-structured network.
- Service processing consists of basic call and
supplementary service processing which are the serial
and/or parallel executions of network functions in a
coordinated way, such that basic and supplementary
services are provided to the customers.
- Network interworking: A process through
which several networks (IN to IN or IN to non-IN)
cooperate to provide a service.
4.2.1 Service Requirements
The goal of work for IN is to define a new architectural
concept that meets the needs of telecommunication
service providers to rapidly, cost effectively, and vendor-
independently satisfy their existing and potential market
needs for services, and to improve the quality and reduce
the cost of network service operations and management
Garra93. In [Q1201] the following overall service
requirements are given when defining the IN architecture:
- it should be possible to access services by the usual user
network interface (e.g. POTS, ISDN);
- it should be possible to access services that span multiple
networks;
- it should be possible to invoke a service on a call-by-call
basis or for a period of time, in the latter case the
service may be deactivated at the end of the period;
- it should be possible to perform some access control to a
service;
- it should be easy to define and introduce services;
- it should be possible to support services involving calls
between two or more parties;
- it should be possible to record service usage in the network
(service supervision, tests, performance information,
charging);
- it should be possible to provide services that imply the use of
functions in several networks;
- it should be possible to control the interactions between
different invocations of the same service.
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Service requirements for service creation refer to the
network capabilities that are used by network operators
for the provision of service creation services to
customers.
Service requirements for service management refer to the
network capabilities that are necessary for the provision
of service management services to customers.
Service requirements for service processing refer to the
network capabilities that are necessary for the provision,
from a customer's point of view, of basic and
supplementary services by an IN-structured network
[Q1201]. The IN is primarily a network concept that
aims for efficient creation, deploynent and management
of supplementary services that enhance basic services.
Hence, from a customers point of view the provision of
services is transparent, the customer is unaware whether
the service is provided in an IN way. Service processing
requirements can be identified for service and access
capabilities. The service capabilities of IN can be applied
to the support of supplementary services for the following
basic services [Q1201]:
- bearer services including speech, audio and data
- teleservices as telephony, telefax and videotex
- broadband interactive services
- broadband distribution services
The access capabilities of IN should be applicable to all
telecommunications networks, such as Public Switched
telecommunications Networks (PSTN), including
Integrated Services Digital Networks (ISDN), both
narrowband and broadband, packet-switched public data
networks, and mobile networks. Allthough, IN CS1
enables only the use of PSTN, PLMN (Public Land
Mobile Network) and ISDN, IN should enable service
providers to define their own services, independent of
service-specific developments by equipment suppliers.
CS1 is intended to address services with high commercial
value, focusing at addressing flexible routing, charging,
and user interaction services. The list of benchmark
services and features will be listed later on.
Standardization of these services, however, is not
CCITT’s role. An important characteristic is that the
services will be technologically feasible and
understandable, but do not significantly impact existing
deployed technology. In this context, services have been
categorized by CCITT as follows: Duran92
All type A services are invoked on behalf of and
directly affect a single user. Most type A services
can be invoked only during call setup of tear down
and fall in the category of “single-user, single-
ended (no requirements for representing end-to-end
messaging or control), single point-of-control (no
requirement fro representing interaction points
between multiple service logic programs), and
single-bearer capability (one media profile)”. Type
A services may be used in conjunction with other
services, switch-based or not, of any type, to form
a more complete service package.
Type B services can be invoked at any point during
the call. These services may be invoked on behalf
of and directly impact one or more users. Feature
interaction and arbitration, and topology
manipulation are capabilities that need to be
addressed to deploy these services. Note that it is
possible to use type A capabilities to enhance some
existing type B services.
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The services addressed by CS1 fall under type A services.
The type A category lead to a series of advantages in the
context of CS1 standardization. First, they represent a
wide range of services of proven value. Second, these
services depend on well-understood control relationships
between network components and this represents an
achievable target within required time frame of IN CS1
product deployment in 1993. Finally, complexity in the
transition to rapid service delivery process is minimized
both for service provider and for the equipment
manufacturer Duran92.
4.2.2. Network Requirements
Overall network requirements of IN are stated in [Q1201]
as follows:
- it should be possible to move cost-effectively from existing
network bases to target network bases in a practical and
flexible manner
- it should be possible to reduce redundancies among network
functions in physical entities
- it should be possible to allow for the flexible allocationn of
etwork functions to physical entities
- there is a need for communication protocols that allow
flexibility in the allocation of functions
- it should be possible to create new services from network
functions in a cost and time efficient manner
- it should be possible to quarantee the integrity of the
etwork when new service is being introduced
- it should be possible to manage network elements and
network resources such that quality of service and network
performance can be quaranteed
Network requirements for service creation refer to the
network capabilities that are necessary from a network
operator point of view for the creation of new
supplementary services. The service creation process
consists of specification, development and verification
steps.
Network requirements for service management refer to
the network capabilities that are necessary from a
network operator point of view to support the proper
operation of services
Network requirements for service processing refer to the
network capabilities that are necessary for the provision,
from a network operator point of view, of basic and
supplementary services by an IN-structured network
[Q1201]. The main network requirements for service
processing stem from the inability of network operators
of traditional "non-IN" networks to rapidly create and
deploy new supplementary services. To overcome this
inability the IN aims for:
- rapid service implementations by means of
reusable network functions;
- modularization of network functions;
- standardized communication between network
functions via service independent interfaces.
To achieve the goal of fast service implementation, the IN
Service Processing Model is introduced (Figure 4-3), and
will be studied here in some detail.
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Figure 4-3. IN Service Processing Model.
The three main elements of this model are: the basic call
processes, the "hooks" that allow the basic call processes
to interact with IN service logic, and IN service logic that
can be "programmed" to implement new supplementary
services. For these elements the main principles are
described below:
- The basic call process should be available all
over the network and is designed to support, with optimal
performance, services that do not require special features.
In order to achieve flexibility in service processing, the
basic call process needs to be modularized into service-
independent sub-processes such that these can be
executed autonomously (without interference from the
outside during execution).
- "Hooks" are to be added to the basic call process
forming the links between the individual basic call sub-
processes and the service logic. The "hooks" are able to
start an interaction session with the IN service logic. For
this it should continuously check the basic call process
for the occurrence of conditions on which an interaction
session with IN service logic should be started. During an
interaction session the basic call process can be
temporarily suspended.
- IN service logic uses a programmable software
environment that needs to be developed to allow fast
implementation of new supplementary services. New
supplementary services can be created by means of
"programs" containing IN service logic. The IN service
logic is able, via the "hooks" functionality, to interact
with the basic call process. In this way IN service logic
can control the sub-processes in the basic call process and
the sequencing of these sub-processes.
Thus, by changing logic at the service control point and
modifying network data, a new service that uses existing
network capabilities can readily be implemented.
In addition In service logic can decide to terminate an
interaction session with the basic call process. The basic
call process will then resume its execution as specified by
the IN service logic. In order to allow fast service
implementation, the IN service logic should have a
logical view of the network resources that constitute the
basic call process and additional (specialised) network
functions. For proper service processing, the following
principles apply:
- it should be possible to distribute resources
between services in a well balanced way;
- it should be possible for IN supported services
to share resources with non-IN supported
services;
- it should be possible to provide a different
method of resource data management from the
current embedded method;
- it should be possible to introduce IN supported
services specific resources.
To define an IN architecture including the network
elements within this architecture, there is a need for a call
model that describes the real-time behaviour of call
control capabilities for the provision of basic and
supplementary services. In order to be consistent with the
principles of the above-described IN service processing
model, the IN call model should cover the following
aspects:
- it should specify which basic services can be
supported by the model;
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- it should model the basic call processes (each
individual basic service may require its own IN
basic call process);
- it should describe trigger mechanisms
("hooks") that allow the IN basic call process to
interact with service logic;
- it should provide a logical view (from the
service logic point of view) of call processing
functions and network resources, which as a
consequence allows fast service implemen-
tation;
- it should specify the mechanisms according to
which an IN-basic call process may interact
with the service logic (e.g. single-ended
interactions, simultaneous interactions, service-
logic initiated interactions, etc.);
- it should be evolvable from the existing
technology base.
The CS1 Call Model is presented in detail later in chapter
4.3.2.1.4 of this tutorial. [Q1204]
4.3 IN Conceptual Model
The IN Conceptual Model (INCM) is defined in the
CCITT Recommendation Q.1201. The conceptual model
is divided into four planes and it forms the basis for the
standardation work. The IN conceptual Model was
designed to serve as a modelling tool for the Intelligent
Network. It is also a tool that can be used to design the
IN architecture to meet the following main objectives
Q1201:
service implementation independence
network implementation independence
vendor and technology independence
Each INCM plane represents a different abstract view of
the capabilities provided by an IN-structured network.
These views address service aspects, global functionality,
distributes functionality and physical aspects of an IN (
Figure ).
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Figure 4-4 IN Conceptual Model Error! Reference
source not found.
The Service Plane represents an exclusively service-
oriented view. This view contains no information
whatsoever regarding the implementation of the services
in the network, e.g. an "IN-type" implementation is not
visible. All that is perceived is the network's service-
related behaviour as seen, for example, by a service user.
Services are composed of one or more Service Features
(SFs), which are the "lowest level" of services.
The Global Functional Plane (GFP) models an IN-
structured network as a single entity. Contained in this
view is a global (network-wide) basic call processing
(BCP) SIB, the service independent building blocks
(SIBs), and point of initiation (POI) and point of return
(POR) between the BCP and a chain of SIBs. These are
described in detail in chapter 4.3.3.1.
The Distributed Functional Plane (DFP) models a
distributed view of an IN-structured network. Each
functional entity (FE) may perform a variety of functional
entire actions (FEAs). Any given FEA may be performed
within different functional entities. However, a given
FEA may not be distributed across functional entities.
Within each functional entity, various FEAs may be
performed by one or more elementary functions. The
manner in which elementary functions result in FEAs is
for further study.
Service-independent building blocks (SIBs) are realised
in the distributed functional plane (DFP) by a sequence
of particular FESs performed in the functional entities.
Some of these FEAs result in information flows between
functional entities. The information flows consist of
messages which exhance information between functional
entities. The messages comply with OSI structures and
principles (see chapters 4.3.1.2 and 4.4.3).
The Physical Plane models the physical aspects of IN-
structured networks. The model identifies the different
physical entities and protocols that may exist in real IN-
structured networks. It also indicates which functional
entities are implemented in which physical entities.
The entities contained in adjacent planes of the INCM are
related to each other. The nature of the relationship is as
follows (Q1201):
- Service plane to GF plane: Service features
within the service plane are realised in the GF plane by a
combination of global service logic and SIBs including
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the basic call process SIBs. This mapping is related to the
service creation process.
- GF plane to distributed functional (DF) plane:
Each SIB identified in the GF plane must be present in at
least one FE in the DF plane. A SIB may be realised in
more than one FE. Thus, cooperation of several FEs may
be needed. The service logic in the GF plane maps onto
one or more DSLs in the DF plane. This mapping is
related to the service creation process.
- DF plane to physical plane: FEs identified in the
DF plane determine the behaviour of the physical entities
(PEs) onto which they are m mapped. Each FE must be
mapped onto one physical entity, but, each PE contains
one or more FEs. Relationships between FEs, identified
in the DF plane, are specified as protocols in the physical
plane. DSLs may be dynamically loaded into physical
entities and this mapping is related to the service
management process.
Let us consider the structures of the INCM planes more
thoroughly starting from the physical plane.
4.3.1 Physical Plane
The physical plane is the lowest layer in the IN
architecture. It takes action of how the network itself is
implemented. It describes the physical architecture
alternatives for an IN-structured network in terms of
potential physical systems, referred to as physical entities
(PE), in a network, and interfaces between these Physical
Entities (Figure 4-5). One or more Functional Entities
from the Distributed Functonal Plane may be realized in a
Physical Entity on the physical plane, and one or more
relationships from the Distributed Functional Plane may
map into an interface on the physical plane. The physical
plane architecture describes how functional architecture
map into Physical Entities and interfaces Garra93. Also
the requirement for physical plane architecture is that
vendors must be able to develop Physical Entities based
on the mapping of Functional Entities and the standard
interfaces. Q1201
Figure 4-5. IN Physical Plane Architecture.
4.3.1.1 Physical Entities
The CCITT recommendation Q.1215 defines the Physical
Entities (PE) used by IN. It also describes the interfaces
between PEs and which IN functionalities are included
into them from the Distributed Functional Plane and
which of them are just optional entities.
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4.3.1.1.1SSP
SSP ( Service Switching Point) is a Physical Entity in the
Intelligent Network that provides the switching
functionality. To make IN capabilities available to all
types of access arrangements, we must develop service
management independently of the access arrangements.
This separation of service management from network
access would allow the same network-wide, IN
capabilities to serve a variety of access arrangements,
from analog lines to wireless, and, in the future, to
broadband and other high-speed optical links. Wyatt91 In
addition to providing users with access to the network (if
the SSP is a local exchange) and performing any
necessary switching functionality, the SSP allows access
to the set of IN capabilities. The SSP contains Detection
Capability to detect requests for IN services. It also
contains capabilities to communicate with other PEs
containing SCF, such as SCP, and to respond to
instructions from the other PEs. Functionally, an SSP
contains a Call Control Function, a Service Switching
Function, and, if the SSP is a local exchange, a Call
Control Agent Function. It also may optionally contain
Service Control Function, and/or a Specialized Resource
Function, and/or a Service Data Function. The SSP may
provide IN services to users connected to subtending
Network Access Points. Q1201
The SSP is usually provided by the traditional switch
manufacturers. These switches are programmable and
they can be implemented using multipurpose processors.
The main difference of SSP from an ordinary switch is in
the software where the service control of IN is separated
from the basic call control.
4.3.1.1.2NAP
A NAP ( Network Access Point) is a PE that includes only
the CCAF and CCF functional entities. It may also be
present in the network. The NAP supports early and
ubiquitous deployment of IN services. This NAP cannot
communicate with an SCF, but it has the ability to
determine when IN processing is required. It must send
calls requiring IN processing to an SSP. Q1201
4.3.1.1.3SCP
Functionally, an SCP contains Service Control Function
(SCF) and optionally also Service Data Function (SDF).
The SCF is implemented in Service Logic Programs
(SLP). The SCP is connected to SSPs by a signalling
network. Multiple SCPs may contain the same SLPs and
data to improve service reliability and to facilitate load
sharing between SCPs. In case of external Service Data
Point (SDP) the SCF can access data through a signalling
network. The SDP may be in the same network as the
SCP, or in another network. The SCP can be connected to
SSPs, and optionally to IPs, through the signalling
network. The SCP can also be connected to an IP via an
SSP relay function. Q1201
The SCP comprises the SCP node, the SCP platform, and
applications. The node performs functions common to
applications, or independent of any application; it
provides all functions for handling service-related,
administrative, and network messages. These functions
include message discrimination, distribution, routing, and
network management and testing. For example, when the
SCP node receives a service-related message, it
distributes the incoming message to the proper
application. In turn, the application issues a response
message to the node, which routes it to the appropriate
network elements. Ambro89
The SCP node gathers data on all incoming and outgoing
messages to assist in network administration and cost
allocation. This data is collected at the node, and
transmitted to an administrative system for processing.
Ambro89
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The SCP node also measures the frequency of SCP
hardware and software failures, resource usage, overload
counts, and so on. It provides information needed to
perform maintenance procedures, thus minimizing the
impact of failures on system performance. The node may
take action to prevent and correct the overload at the node
or at a particular application. Ambro89
4.3.1.1.4AD
The Adjunct (AD) PE is functionally equivalent to an
SCP (i.e. it contains the same functional entities) but it is
directly connected to and SSP. Communication between
and Adjunct and an SSP is supported by a high speed
interface. This arrangement may result in differing
performance characteristics for an adjunct and an SCP.
The application layer messages are identical in content to
those carried by the signalling network to an SCP. Q1201
An Adjunct may be connected to more than one SSP and
an SSP may be connected to several Adjuncts.
4.3.1.1.5IP
The IP provides resources such as customized and
concatenated voice announcements, voice recognition,
and Dual Tone Multi-Frequencies (DTMF) digit
collection, and contains switching matrix to connect users
to these resources. The IP supports flexible information
interactions between a user and the network.
Functionally, the IP contains the Special Resource
Function. The IP may directly connect to one or more
SSPs, and/or may connect to the signalling network.
Q1201
An SCP or Adjunct can request an SSP to connect a user
to a resource located in an IP that is connected to the SSP
from which the service request is detected. An SCP or
Adjunct can also request the SSP to connect a user to a
resource located in an IP that is connected to another SSP.
Q1201
4.3.1.1.6SN
The Service Node can control IN services and engage in
flexible information interactions with users. The SN
communicates directly with one or more SSPs, ech with a
point-to-point signalling and transport connection.
Functionally, the SN contains an SCF, SDF, SRF, and an
SSF/CCF. This SSF/CCF is closely coupled to the SCF
within the SN, and is not accessible by external SCFs.
Q1201
In a manner similar to an Adjunct, the SCF in an SN
receives messages from the SSP, executes SLPs, and
sends messages to the SSP. SLP in an SN may be
developed by the same Service Creation Environment
used to develop SLPs for SCPs and Adjuncts. The SRF in
an SN enables the SN to interact with users in a manner
similar to an IP. An SCF can request the SSF to connect a
user to a resource located in an SN that is connected to
the SSP from which the service request is detected. An
SCF can also request the SSP to connect a user to a
resource located in an SN that is connected to an another
SSP. Q1201
4.3.1.1.7SSCP
The SSCP (Service Switching and Control Point) is a
combined SCP and SSP in a single node. Functionally, it
contains an SCF, SDF, CCAF, CCF, and SSF. The
connection between the SCF/SDF functions and the
CCAF/CCF/SSF functions is proprietary and closely
coupled, but it provides the same service capability as an
SSP and SCP separately. This node may also contain SRF
functionality, i.e. SRF as an optional functionality. The
interfaces between the SSCP and other PEs are the same
as the interfaces between the SSP and other PEs, and
therefore will not be explicitly stated. Q1201
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4.3.1.1.8SDP
The SDP contains the customer and network data which
is accessed during the execution of a service.
Functionally, the SDP contains an SDF. Q1201 It
contains data used by Service Logic Programs to provide
individualized services. Functionally, and SDP contains a
Service Data Function. It can be accessed directly by an
SCP and/or SMP, or through the signalling network. It
can also access other SDPs in its own or other networks.
Q1201
4.3.1.1.9SMP
The Service Management Point/Service Management
System performs service management control, service
provision control, and service deployment control.
Examples of functions it can perform are database
administration, network surveillance and testing, network
traffic management, and network data collection.
Functionally, the SMP contains the Service Management
Function and, optionally, the Service Management
Access Function and the Service Creation Environment
Function. The SMP can access all other Physical Entities.
Q1201
A Service Management System is the operations system
through which network operator and service subscriber
personnel manage SCPs and related service applications
(programs and databases) in an IN. More than one SMS
may be associated with the IN; the network operating
company may want a separate SMS for each IN service or
a single SMS for several IN services. Ambro89
Physically, the SMS resides in a multipurpose computer.
Processing power and database size requirements
normally govern the choice of a specific computer. The
SMS manages a private network consisting of switched
and leased line connected to a set of keyboard or display
terminals through which network operator and service
subscriber personnel gain interactive messages to the
system. Ambro89
4.3.1.1.10 SCEP
The Service Creation Environment Point is used to
define, develop, and test an IN service, and to input it into
the SMP. Functionally, it contains the Service Creation
Environment Function. The SCEP interacts directly with
the SMP. Q1201
4.3.1.1.11 SMAP
The Service Management Access Point provides some
selected users, such as service managers and customers,
with access to the SMP. One possible use of the SMAP is
to provide one single point of access for a given user to
several SMPs. The SMAP functionally contains a Service
Management Access Function. The SMAP directly
interacts with the SMP. Q1201
4.3.1.2 Interfaces between PEs
In the Physical Plane Architecture several standardized
interfaces are stated. These interfaces are: SCP-SSP, AD-
SSP, IP-SSP, SN-SSP, SCP-IP, AD-IP, and SCP-SDP.
Existing lower layer protocols are proposed for these
candidate interfaces to carry the application layer
messages required by IN services. As such, the focus of
the standardization effort for CS-1 is on the applications
layer protocols. At the application layer, the message sent
that the different interfaces carry should reflect the same
semantic content, even though the application layer
message may be encoded or formatted differently. For
example, the messages between the SSF in an SSP and
the SCF in an SCP, Adjunct or SN should contain the
same information. The following sections give some
proposed protocols for use on these interfaces. Q1201
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4.3.1.2.1SCP-SSP interface
The proposed underlying protocols platform for the
interface between an SCP and an SSP is Transaction
Capabilities Application Part (TCAP) on Signalling
Connection Control Part (SCCP)/Message Transfer Part
(MTP) of SS7. Q1201 So, the SCP-SSP interface in CS-1
is using CCITT SS7 protocol stack to communicate
(signal) with each other. The interface could also be
something else at the lowest layer protocols of the SS7 in
order to achieve, for example, high-speed signalling
between these PEs. That is why, the IN standardization is
mainly focused on the application layer protocols.
4.3.1.2.2AD-SSP interface
The proposed underlying protocol platform for the AD-
SSP interface is TCAP. The physical interface has not
been specified, but a number of alternative standard
protocols could be used.
4.3.1.2.3IP-SSP interface
This interface is used for communications between an IP
and an SSP as well as for communication between an IP
and an SCP which is being relayed through an SSP. The
proposed underlying protocol platform for the interface
between an IP and an SSP is ISDN Basic Rate Interface
(BRI), Primary Rate Interface (PRI) (or both), or SS7.
Q1201
If a BRI or PRI is used, the ISDN D-channel connecting
an IP to an SSP carries application layer information
between an SCF and an SRF, and supports the setup of B-
channel connections to the IP. Information is passed from
an SCF to an SRF (e.g. collected information and billing
measurements) is embedded in the Facility Information
Element (FIE). The FIE can be carried by a number of
Q.931 messages, like SETUP and DISCONNECT. The
FIE can also be carried by the FACILITY message in
Q.931. This possibility provides for the flexibility to
convey application layer information without affecting
the connection state of the call. Q1201
4.3.1.2.4SN-SSP interface
The proposed underlying protocol platform for the
interface between an SN and an SSP is ISDN BRI, PRI
(or both). An SN and an SSP exchange application layer
messages over an ISDN D-channel using common
element procedures of CCITT Recommendations Q.932.
This communication may occur on a separate D-channel
from the channel that carries the common element
procedure messages. These channels may also be
separate. Q1201
4.3.1.2.5SCP-IP interface
The proposed underlying protocol platform for an
interface between an SCP and an IP is TCAP on
SCCP/MTP of the SS7 protocol stack. Q1201
4.3.1.2.6AD-IP interface
The proposed underlying protocol platform between an
AD and an IP is TCAP. The physical interface has not
been specified, but a number of alternative standard
protocols could be used. Q1201
4.3.1.2.7SCP-SDP interface
The proposed underlying protocol platform for the
interface between an SCP and an SDP is TCAP on
SCCP/MTP of SS7 protocol stack. In existing systems
the SCP - SDP interfaces have been implemented in
many proprietary ways, a typical one being a fast remote
operations protocol using a Local Area Network (LAN).
Q1201
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4.3.1.2.8User interfaces
A user is an entity external to the IN that uses IN
capabilities. IN users may employ the access interfaces
described below to invoke various IN service capabilities.
For example, users can affect the routing of a call, send
and receive information from the network, screen calls,
and update service parameters. Users are served by
existing network interfaces. Q1201
It is important to ensure that IN should continue to
support existing services and capabilities. In addition, the
current restrictions imposed by each of the interface
technologies described below must be considered when
deploying IN services. For example, calling party
information may or may not be available at a given
interface and, therefore, may or may not be provided to
the SCF. Q1201
End users are using analogue interface signalling, or
ISDN access signalling arrangements. IN user-network
interactions include providing stimuli, such as off-hook or
DTMF digit signalling, which determine further IN
action. Q1201
Out-of-band (i.e. D_channel) signalling provides ISDN
users with additional capabilities for accessing potential
IN services. When originating a call, an ISDN user
identifies the bearer capability to be associated with the
call. IN service logic can use this information to
determine how the call should be handled (e.g. how to
route the call). Q1201
4.3.2 Distributed Functional Plane
The global Distributed Functional Plane (DFP) is of
primary interest to network designers and providers. It
describes the functional architecture of an IN-structured
network in terms of units of network functionality (Figure
4-6). These functionalities are referred to as Functional
Entities (FE). The information that flows between
Functional Entities are referred to as relationships (rN).
The functional entities are described independently of
how the functionality is physically implemented or
deployed in the network. SIB’s on the global functional
plane are realized on the Distributed Functional Plane by
a sequence of Functional Entity Actions (FEA) and
resulting information flows. Garra93
Figure 4-6. Distributed functional plane architecture.
The DFP architecture provides flexibility to support a
large variety of services and facilitates the evolution of IN
by organizing the functional capabilities in an open-ended
and modular strtucture to achieve service independence.
The DFP architecture is vendor/implementation
independent, thereby providing the flexibility for multiple
physical networking configuration and placing no
constraints on national network architecture beyond the
network and interface standards which will be developed
for IN structured networks. The definition of the DFP
architecture initially accomodates service execution
capabilities and will accomodate service creation and
service and network management capabilities when they
become available. Q1201
A Functional Entity is a unique group of functions in a
single location and a subset of the total set of functions
required to provide a service. One or more Functional
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Lappeenranta University of Technology and Telecom Finland 34
Entities can be located in the same Physical Entity.
Different Functional Entities contain different functions,
and may also contain one or more of the same functions.
In addition, one Functional Entity cannot be split between
two Physical Entities; the Functional Entity is mapped
entirely within a single Physical Entity. Finally, duplicate
instances of a FE can be mapped to different PEs, though
not the same PE. Q1201
4.3.2.1 Definition of FEs
This section gives a description of the Functional Entities
at the Distributed Functional Plane related to IN service
execution and how they are mapped to the Physical Plane
architecture.
4.3.2.1.1CCAF
The CCAF is the Call Control Agent Function that
provides access for users. It is the interface between user
and network call control functions. It has the following
characteristics: It Q1201
a) provides for user access, interacting
with the user to establish, maintain,
modify and release, as required, a call or
instance of service;
b) accesses the service-providing
capabilities of the Call Control
Function, using service requests (e.g.
setup, transfer, hold, etc.) for the
establishment, manipulation and release
of a call or instance of service;
c) receives indications relating to the call
or service from the CCF and relays
them to the user as required;
d) maintains call/service state information
as perceived by this functional entity;
4.3.2.1.2CCF
The CCF is the Call Control Function in the network that
provides call/connection processing and control. It Q1201
a) establishes, manipulates and releases
call/connection instances as “requested”
by the CCAF;
b) provides the capability to associate and
relate CCAF functional entities that are
involved in a particular call and/or
connection instance (that may be on SSF
requests);
c) manages the relationship between CCAF
functional entities involved in a call (e.g.
supervises the overall perspective of the
call and/or connection instance);
d) provides trigger mechanism to access IN
functionality (e.g. passes events to the
SSF);
e) is managed, updated and/or otherwise
administred for its IN-related functions
(i.e. trigger mechanisms) by a Service
Management Function;
4.3.2.1.3SSF
The SSF is the Service Switching Function, which,
associated with the CCF, provides the set of functions
required for interaction between the CCF and Service
Control Function. It Q1201
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a) extends the logic of the CCF to include
recognition of service control triggers
and to interact with the SCF;
b) manages signalling between the CCF
and the SCF;
c) modifies call/connection processing
functions (in the CCF) as required to
process requests for IN provided service
usage under the control of the SCF;
d) is managed, updated and/or otherwise
administred by an SMF;
4.3.2.1.4SSF/CCF Model
The SSF/CCF model described below include the Basic
Call Manager (BCM), the IN-Switching Manager (IN-
SM), the Feature Interactions Manager (FIM)/Call
Manager (CM), the relationship of the BCM to the IN-
SM, the relationship of the BCM and IN-SM to the
FIM/CM, and the functional separation provided in the
SSF/CCF (Figure 4-7). [Q1214]
a) BCM - The entity in the CCF that provides basic call
and connection control to establish communication paths
for users and interconnects such communication paths,
that detects basic call and connection control events that
can lead to the invocation of IN service logic instances or
should be reported to active IN service logic instances,
and that manages CCF resources required to support basic
call and connection control. The BCM interacts with the
FIM/CM as described in the FIM/CM description below.
b) IN-SM - The entity in the SSF that interacts with the
SCF in the course of providing IN service features to
users. It provides the SCF with an observable view of
SSF/CCF call/connection processing activities, and
provides the SCF with access to SSF/CCF capabilities
and resources. It also detects IN call/connection
processing events that should be reported to active IN
service logic instances, and manages SSF resources
required to support IN service logic instances. The IN-SM
interacts with the FIM/CM as described below.
c) FIM/CM - The entity in the SSF that provides
mechanisms to support multiple concurrent instances of
IN service logic instances on a single call. In particular,
the FIM/CM can prevent multiple instances of IN an
non-IN service logic instances from being invoked. The
ability of the FIM/CM to arbitrate between multiple
instances of IN and non-IN service logic instances is for
further study. The FIM/CM integrates these interactions
mechanisms with the BCM and IN-FM to provide the
SSF with a unified view of call/service processing
internal to the SSF for a single call.
d) BCM Relationship to IN-SM - The relationship that
encompasses the interaction between the BCM and the
IN-SM, through the FIM/CM. The information flow
related to this interaction is not externally visible and is
not standardized for CS-1. However, an understanding of
this subject is required to identify how basic call and
connection processing and IN call/connection processing
may interact.
e) BCM and IN-SM Relationships to FIM/CM - The
relationships that encompass the interaction between the
BCM and FIM/CM, and the IN-SM and the FIM/CM.
The information flows related to these interactions are not
externally visible and are not standardized for CS-1.
However, an understanding of this subject is required in
order to unify the BCM, IN-SM and FIM/CM.
f) Functional Separation in the SSF/CCF. The functional
separation of processes and resources in the SSF/CCF
that provides a means of handling service logic instance
interactions for CS-1. This functional separation services
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to isolate single-ended service logic instances related to
the calling party from single-ended service logic instances
related to the called party for the same call. Within the
scope of CS-1, there is no functionality in the SSF for
handling service feature interactions between the separate
SSF calling party processes and SSF called party
processes.
SSF
CCF
SCF Access Manager
IN Switching StateModel Instance< IN-SSM >> IN-SSM Events >< REsource Control >
Basic Call Manager< BCSM >< Basic Call Triggers >< Basic Call Events >
SRF
IN Local Resource DataManager
IN LocalResource data
Non-IN FeatureManager FIM/CM
Basic CallResource dataManager
CCAF
Basic CallResource data Bearer Control CCAF
SCF
SLPI A
IN-SM
BCM
Figure 4-7. SSF/CCF Model
4.3.2.1.4.1 BCSM
The BCSM is a high-level finite state machine description
of CCF activities required to establish and maintain
communication paths for users. As such, it identifies a set
of basic call and connection activities in a CCF and
shows how these activities are joined together to process
a basic call and connection (i.e., establish and maintain a
communication path for a user). [Q1214]
Many aspects of the BCSM are not externally visible to
IN service logic instances. However, aspects of BCSM
will be the subject of standardization. As such, the BCSM
is primarily an explanatory tool for providing a
representation of CCF activities that can be analysed to
determine which aspects of the BCSM will be visible to
IN service logic instances, if any, and what level of
abstraction and granularity is appropriate for this
visibility.
The BCSM identifies points in basic call and connection
processing when IN service logic instances are permitted
to interact with basic call and connection control
capabilities. In particular, it provides a framework for
describing basic call and connection events that can lead
to the invocation of IN service logic instances or should
be reported to active IN service logic instances, for
describing those points in call and connection processing
at which these events are detected, and for describing
those points in call and connection processing when the
transfer of control can occur.
Figure 4-8 shows the key components that have been
identified to describe a BCSM, to include: Points in Call
(PICs), Detection Points (DPs), transitions, and events.
PICs identify CCF activities required to complete on or
more basic call/connection states of interest to IN service
logic instances. DPs indicate points in basic call and
connection processing at which transfer of control can
occur. Transitions indicate the normal flow of basic
call/connection processing from one PIC to another.
Events cause transitions into and out of PICs.
Information Flows [Q1214] (e.g. between SSF/CCF and
SCF) corresponding to Events and PICs are represented
by Operations [Q1218] and modelled as Application
Service Elements (ASEs), these application protocol
related concepts are discussed in more detail in chapter
4.4.3.
The BCSM for CS-1 should model existing switch
processing of basic two-party calls, and should reflect the
functional separation between the originating and
terminating portions of calls. In addition, though CCAF
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functionality is not explicitly modelled in the BCSM, a
mapping is required between access signalling events and
BCSM events, for each access arrangement supported by
CS-1.
Since the BSCM is generic, it may describe events that do
not apply to certain access arrangements. It is important
to understand and describe how each access arrangement
applies to the BCSM.
1. O_Null & Authorize Origination attempt
2. Collect Info
1
3. Analyze Info
2
4. Routing & Alerting
5. O_Active
7
3
4
5
6
8
9
106. Exception
Orig. Attempt_Authorized
Collected_Info
O_Abandon
Analyzed_Info
O_Disconnect
O_Mid_Call
Route_Select_Failure
O_Called_Party_Busy
O_No_Answer
Key: Transition
Detection Point (DP)
Point in Call (PIC)
Figure 4-8. Originating BCSM for CS1
4.3.2.1.4.2 Originating BCSM for CS-1
As an axample we describe here the originating half of
the BCSM for CS1. It corresponds to that portion of the
BCSM associated with the originating party (see Figure
4-8). The description for each of the PICs in the
originating half of the BCSM are described below
[Q1214]:
1) O_Null&Authorize_Origination_Atempt
Entry Event: Disconnect and clearing of a previous call (DPs 9 -
0_Disconnect and 10 - O_Abandon), or default handling of exeptions
by SSF/CCF completed.
Functions:
- Interface (line/trunk) is idled (no call exists, no call reference exists,
etc.) Supervision is being provided.
- Given an indication from an originating party of a desire to place an
outgoing call (e.g., offhook, Q.931 Setup message, ISDN-UP IAM
message), the authority/ability of the party to place the call with given
properties (e.g., bearer capability, line restrictions) is verified. The types
of authorization to be performed may vary for different types
of originating resources (e.g., for lines vs. trunks).
Exit Event:
- Indication of desire to place outgoing call (e.g., offhook, Q.931 Setup
message, ISDN-UP IAM message) and authority/ability to place
outgoing call verified (DP 1 - Origination_Attempt_Authorized)
- Authority/ability to place outgoing call denied (Exception)
Corresponding Q.931 Call State: 0. Null
2) Collect_Information
Entry Event: Indication of desire to place outgoing call (e.g., offhook,
Q.931 Setup message, ISDN-UP IAM message) and authority/ability to
place outgoing call verified (DP1-Origination_Attempt_ Authorized)
Functions:
- Initial information package/dialling string (e.g., service codes,
prefixes, dialled address digits) being collected from originating party.
Information being examined according to dialling plan to determine end
of collection. No further action may be required if an en bloc signalling
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method is in use (e.g., an ISDN user using en bloc signalling, an
incoming SS No. 7 trunk).
Exit Events:
- Availability of complete initial information package/dialling string
from originating party. (This event may have already occurred in the
case of en bloc signalling, in which case the waiting duration in this PIC
is zero.) (DP 2- Collected_Info)
- Originating party abandons call. (10 - O_Abandon)
- Information collection error has occurred (e.g., invalid dial string
format, digit collection time-out) (Exception)
3) Analyze_Information
Entry Event: Availability of complete initial information
package/dialling string from originating party. (DP 2 - Collected_Info)
Function: Information being analysed and/or translated according to
dialling plan to determine routing address and call type (e.g., local
exchange call, transit exchange call, international exchange call).
Exit Events:
- Availability of routing address and nature of address. (DP 3 -
Analyzed_Info)
- Originating party abandons calls. (DP 10 - O_Abandon)
- Unable to analyse and translate dial string in the dialling plan (e.g.,
invalid dial string) (Exception)
4) Routing and Alerting
(encompasses the following general BCSM PICs: Select_Route,
Authorize_Call_Setup, Call_Sent, and O_Alerting)
Entry Events:
- Availability of routing address and call type. (DP 3 - Analyzed_Info)
Functions:
- Routing address and call type being interpreted. The next route is
being selected. This may involve sequentially searching a route list,
translating a directory number into physical port address, etc. The
individual destination resource out of a resource group (e.g., a multi-line
hunt group, a trunk group) is not selected. In some cases (e.g., an
analogue line interface), a single resource (not a group) is selected.
- Authority of originating party to place this particular call being
verified (e.g., checking business group restrictions, toll restrictions,
route restrictions). The types of authorization checks to be performed
may depend upon the type of originating resource (e.g., line vs. trunk).
- Call is being processed by the terminating half BCSM. Continued
processing of call setup (e.g., ringing, audible ring indication) is taking
place. Waiting for indication from terminating half BCSM that the call
has been answered by terminating party.
Exit Events:
- Indication from the terminating half BCSM that the call is accepted
and answered by terminating party (e.g., terminating party goes offhook.
Q.931 Connect message received. ISDN-UP Answer message received)
(DP 7 - O_Answer)
- Unable to select a route (e.g., unable to determine a correct route, no
more routes on route list) or indication from the terminating half BCSM
that call cannot be presented to the terminating party (e.g., network
congestion) (DP 4 - Route_Select_Failure)
- Indication from the terminating half BSCM that the terminating party
is busy (DP 5 - O_Called_Party_Busy)
- Indication from the terminating half BCSM that the terminating party
does not answer within a specified time period (DP 6 - O_No_Answer)
- Originating party abandons call (DP 10 - O_Abandon)
- Authority of calling party to place thiscall is denied (e.g., business
group restriction mismatch, toll restricted calling line) (Exception)
Corresponding Q.931 Call State: 4. Call Delivered
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5) O_Active
Entry Event: Indication from the terminating half BCSM that the call is
accepted and answered by terminating party. (DP 7 - O_Answer)
Function: Connection established between originating and terminating
party. Message accounting/charging data may be being collected. Call
supervision is being provided.
Exit Events:
- A service/service feature request is received from the originating party
(e.g., TDMF, hook flash, ISDN feature activator, Q.931 HOLD or
RETrieve message). (DP 8 - O_Mid_Call)
- A disconnect indication (e.g., onhook, Q.931 Disconnect message, SS7
Release message) is received from the originating party. or received
from the terminating party via the terminating half BCSM. (DP -
O_Disconnect)
- A connection failure occurs (Exception)
6) O_Exception
Entry Event: An exception condition is encountered (as described above
for each PIC)
Function: Default handling of the exception condition is being provided.
This includes general actions necessary to ensure no resources remain
inappropriately allocated, such as
- If any relationships exist between the SSF and SCF(s), send an Error
information flow to the SCF(s) closing the relationships and indicating
that any outstanding call handling instructions will not run to
completion (e.g., see Annex B).3
- If an SCF previously requested that call parameters be provided at the
end of the call (see the Call Information Request information flow in
section 6), these should be included in the Error information flow.
- The SSF/CCF should make use of vendor-specific procedures to
ensure release of resources within the SSF/CCF so that line, trunk, and
other resources are made available for new calls.pt PIC).
Exit Event: Default handling of the exception condition by SSF/CCF
completed (Transition to O_Null & Authorize_Origination_Attempt)
4.3.2.1.5SCF
The SCF is a function that commands call control
functions in the processing of IN provided and/or custom
service requests. The SCF may interact with other
functional entities to access additional logic or obtain
information (service or user data) required to process a
call/service logic instance. It. Q1201
a) interfaces and interacts with SSF/CCF,
SRF and SDF functional entities;
b) contains the logic and processing
capability required to handle IN
provided service attempts;
c) interfaces and interacts with other SCFs,
if necessary;
d) is managed, updated and/or otherwise
administered by an SMF;
4.3.2.1.6SDF
The SDF contains customer and network data for real
time access by the SCF in the execution of an IN
provided service. It Q1201
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a) interfaces and interacts with SCF as
required;
b) interfaces and interacts with other SDFs,
if necessary;
c) is managed, updated and/or otherwise
administered by an SMF;
4.3.2.1.7SRF
The SRF provides the specialized resources required for
the execution of IN provided services (e.g. digit receivers,
announcements, conference bridges, etc.). It Q1201
a) interfaces and interacts with SCF and
SSF (and with the CCF);
b) is managed, updated and/or otherwise
administered by an SMF;
c) may contain the logic and processing
capability to receive/send and convert
information received from users;
d) may contain functionality similar to the
CCF to manage bearer connections to
the specialized resources;
4.3.2.1.8SCEF
This function allows services provided in Intelligent
Network to be defined, developed, tested an input to
SMF. Output of this function would include service logic,
service management logic, service data template and
service trigger information. Q1201
4.3.2.1.9SMAF
This function provides an interface between service
managers and the SMF. It allows service managers to
manage their services (through access to the SMF).
Q1201
4.3.2.1.10 SMF
This function allows deployment and provision of IN
provided services and allows the support of ongoing
operation. Particularly, for a given service, it allows the
coordination of different SCF and SDF instances Q1201.
a) billing and statistic information are
received from the SCFs, and made
available to authorized service managers
through the SMAF;
b) modifications in service data are
distributed in SDFs, and it keeps track
of the reference service data values;
The SMF manages, updates and/or administers service
related information in SRF, SSF and CCF Q1201.
4.3.2.1.11 SCF Model and its relations
The model of the Service Conrol Function and its relation
to other functional entities is shown in Figure 4-9. The
prime function of SCF is the execution of Service Logic
provided in the form ofService Logic Processing
programs (SLPs), and it includes also the SLP execution
supporting functions, such as Service Logic
selection/interaction management, functional entity
access management and SLP provisioning managemant.
[Q1214]
The SCF platform provides a Service Logic Execution
Environment (SLEE) on which the SLPs run to provide
service processing. An SLP is a service application
program invoked by the SLEE and is used to realize
service processing under the control of of thr SLEE. The
Service Logic Execution Manager (SLEM) is the
functionality of SLEE that handles and controls the
service logic execution action. It contains the SLP
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Instances (SLPIs), Service Logic Selection/Interaction
Manager and Resource Manager.
SLPI is a service application program instance invoked
by the SLEE and is used to realize service processing.
SLPI is a dynamic entity that actively controls the flow of
service execution and invokes other SCF functional
routines. Functional routines are the functionality of SCF
to cause a sequence of Functional Entity Actions. This
sequence of Functional Entity Actions provides the
functionality defined for a Service Independent Building
Block (SIB) on the Global Functional Plane. The SIB
concept will be discussed in more detail in chapter
4.3.3.1.
SCF
SLP Library
SLP ManagerService Logic Execution Environment (SLEE)
Serv. LogicSelection/InteractionManager
SLP Instances
Resource Manager
FunctionalRoutine Mgr
Functional Routine Lib.
SCF Data Access Manager+ SD Obj.Lib + Ntw Res.Data
Functional Entity Access Manager
SMF SSF SRF SDF
Service Logic Execution Manager
Figure 4-9. SCF Model
4.3.2.2 Mapping FEs to PEs
The mapping of Distributed Functional Plane FEs to
Physical Plane Architecture PEs is described here. Also a
typical scenario of such mapping is shown here. (Table -
4) Q1201
PE:s SCF SSF/CCF SDF SRF
SCP C C
SN C C C C
AD C C
SSP O C O O
IP C
SDP C
SSCP C C C O
NAP C (CCF
only)C: CoreO: Optional: Not allowed
Table -4. Typical scenarios of FE to PE mapping.
4.3.3 Global Functional Plane
The Global Functional Plane (GFP) is of primary interest
to service designers. Wyatt91 The Global Functional
Plane plane models network functionality from a global,
or network-wide, point of view. As such, the IN
structured network is said to be viewed as a single entity
in the GFP. In this plane, services and Service Features
are redefined in terms of the broad network functions
required to support them. These functions are neither
service nor Service Feature specific and are referred to as
SIB’s (Service-Independent building Block). Q1201
Services identified in the service plane are decomposed
into their service features then mapped onto one or more
SIBs in the GFP. Each SIB is similarly mapped onto one
or more FEs in the Distributed Functional Plane Q1201
(Figure 4-10).
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Figure 4-10. Service decomposition.
4.3.3.1 SIB
IN CS1 contains 14 SIB’s that include algorithm, charge,
compare, translate, basic call process, among others. In
principle many other services described in CCITT
Recommendations Q.1211 could be specified. Raat93
SIBs are standard reusable networkwide capabilities
residing in the Global Functional Plane, used to create
services. As such they are global in nature and their
locations need not to be considered as the entire network
is regarded as a single entity. A Service Feature is
provided by a combination of one or more SIBs. SIBs
have the following characteristics:
SIBs are defined completely independent from
any physical architecture considerations
Each SIB has a unified and stable interface,
with one or more inputs an one or more outputs
SIBs are reusable, monolithic, building blocks,
describing a single complete activity, and used
by the service designer to create services
A SIB can exist independently, or it can coexist with
other SIBs in the same network element. IN-based
services can be distinguished from one another by the
sequence of SIB functions and by the specific parameters
within each SIB. IN CS1 describes 13 SIBs plus a
specialized SIB called Basic Call Process (Table -5).
Algorithm Screen
Charge Service Data Management
Compare Status Notification
Distribution Translate
Limit User Interaction
Log Call Information Verify
Queue
Table -5 The CS1 SIBs.
Basic Call Process (BCP) identifies the normal call
process from which IN services are launched, including
Points Of Initiation (POI) and Points Of Return (POR)
which provide the interface from the BCP to Global
Service Logic (GSL). The GSL describes how SIBs are
chained together to describe Service Features. The GSL
also describes interaction between the BCP and the SIB
chains. Q1201 (Figure 4-11) By definition, SIBs,
including the BCP, are service independent and cannot
contain knowledge of subsequent SIBs. Therefore, GSL
is the only element in the GFP which is specifically
service dependent.
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Figure 4-11. Modelling of Global Functional Plane.
In order to chain SIBs together, knowledge of the
connection pattern, decision options, and data required by
SIBs must be available. Therefore, the pattern of how SIB
are chained together must be maintained within the GFP,
and described in the GSL. The GSL described
subsequential SIB chaining, potential branching, and
where branches rejoin.When an IN supported service is to
be invoked, its GSL is laucnhed at the POI by a triggering
mechanism from the BCP. At the end of chain of SIBs,
the GSL also describes returning point to the BCP by
indicating the specific POR. For a given service or
Service Feature at least one POI is required. However,
depending upon the logic required to support the service
or Service Feature, multiple PORs may be defined.
Q1201
In order to describe Service Features with these generic
SIBs, some elements of service dependency is needed.
Service dependency can be described using data
parameters which enable a SIB to be tailored to perform
the desired functionality. Data parameters are specified
independently for each SIB and are made available to the
SIB through GSL. Two types of data parameters are
required for each SIB, dynamic parameters called Call
Instance Data (CID) and static parameters called Service
Support Data (SSD). Q1201
4.3.3.1.1Call Instance Data
Call Instance Data defines dynamic parameters whose
value will change with each call instance. They are used
to specify subscriber specific details like calling or called
line information. This data can be: made available from
the Basic Call Process SIB (e.g. Calling Line
Identification), generated by a SIB (e.g. translated
number), or entered by the subscriber (e.g. dialled number
or a PIN code). Q1201
Associated with each CID value is a logical name which
is referred to as the CID Field Pointer (CIDFP). If a SIB
requires CID to perform its function, there will be an
associated CIDFP assigned through SSD. For instance,
the Translate SIB’s CID which defines what is to be
translated is called Information. Q1201
Since the CID value can vary with each call instance,
Service Features can be written with data flexibility. In
the above Translate SIB example, one Service Feature
may require translation of a calling number, while another
Service Feature will require translation of the called
number. In both cases, the data required by the SIB is
specified by the information Calling Line Identity (CLI),
but the CIDFP-info changes. Q1201
4.3.3.1.2Service Support Data
Service Support Data defines data parameters required by
a SIB which are specific to the Service Feature
description. When a SIB is included in the GSL of a
service description, the GSL will specify the SSD values
for the SIB. SSD consists of the following parts: Q1201
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Fixed Parameters These are data parameters
whose values are fixed for all
call instances. For instance, the
“File Indicator” SSD for the
Translate SIB need to be
specified uniquely for each
occurrence of that SIB in a
given Service Feature. The
“File Indicator” SSD value is
then said to be fixed, as its
value is determined by the
service/Service Feature
description, not by the call
instance.
Field Pointers Field Pointers identify which
CID is required by the SIB, and
in doing so provide a logical
location for that data. They are
signified by “CIDFP-xxxx”
where “xxxx” names the data
required. For instance,
“CIDFP-info” for the Translate
SIB will specify which CID
element is to be translated. If
more than one CID is required
by a SIB to perform its
function, then the SSD data
parameters will contain
multiple Field Pointers.
4.3.3.1.3The SIB structure
A SIB contructs of both input and output parts (Figure 4-
11). The input part consists of three distinct elements: one
logical starting point, Service Support Data which defines
parameters which are specified by the service description,
and Call Instance Data which are specific to that call
instance. The output part consist of two distinct elements:
one or more logical end points and CID which defines
data parameters specific to that call instance which results
from the execution of that SIB and are required by other
SIBs or the BCP to complete the call service instance.
Figure 4-12. Graphic representation of a SIB. Q1201
4.3.3.1.3.1 Queue SIB
As an example of SIB representation the Queue SIB is
described (Figure 4-12). Q1201 The Queue SIB example
has been described, because it is a multipurpose SIB
which can be used in several Service Features at the
Service Plane. The task of the Queue SIB is to provide
sequencing of IN calls to be completed to a called party.
The Queue SIB provides all the processing needed to
provide queueing for a call, and will specifically: pass the
call if resources are available, queue the call, play
announcements to a caller on queue, and when resources
become available, dequeue the call.
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Figure 4-13. The Queue SIB graphic representation.
The input parameters for the Queue SIB has been
described in the Table -6. The Queue SIB can be used
everywhere the queueing of calls is needed. The Logical
Start indicates the execution for the SIB.
The output parameters are also specified in the Q1201.
The Logical End indicates the result of the execution. The
parameters for Queue SIB are: Resource available, Call
party abandon, Queue timer expiry, Queue full, and an
error. Q1201 The Call Instance Data has the following
parameters and the meanings of output data: Time Spent
in Queue (identifies the total time that a particular call
was queued), Error Cause (identifies the specific
condition which caused an error during the operation of
the SIB). In Error Cause the following errors have been
identified: Invalid Max Active, Invalid Max Number,
Invalid Max Time, Invalid Announcement Parameters,
and Invalid Call Reference.
SSD - Max Active
Specifies the maximum number of active
calls allowed for the resource.
- Max Number
Specifies the maximum number of calls
allowed on queue at a given time.
- Max Time
- Specifies the maximum time the call may
remain on the queue.
- Announcement Parameters
Specify the control values for
announcements. The control values which
can be specified are: Announcement ID
(specifies which announcement is to be
sent), Repetition Requested (specifies if the
announcement is to be repeated), Repetition
Interval (specifies the delay period in
seconds between repetitions) and Maxium
Repetitions (specifies the maximum number
of times the announcement will be
repeated).
- CIDFP-Resource
This CID Field Pointer specifies which Call
Instance Data identifies the resource.
- CIDFP-Error
This CID Field Pointer specifies where in
output Call Instance Data the error cause
will be written.
CID - Call Reference
Identifies the specific call which is a
candidate for queueing.
- Resource
Specifies the data associated with the
CIDFP-Resource which identifies the
resource for which the call will be queued.
Table -6 Queue SIB input resources.
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4.3.3.2 Basic Call Process
The Basic Call Process is responsible for providing basic
call connectivity between parties in the network. The
BCP can be viewed as a specialized SIB which then
provides basic call capabilities including connecting call
with appropriate disposition; disconnecting calls, with
appropriate disposition; and retaining CID for further
processing of that call instance. Q1201
The need for specific POI/POR functionality is that the
same chain of SIBs may represent a different service if
launched from a different point in the BCP. Similarly, the
same chain of SIBs launched from the same point may
represent a different service if returned to the BCP at a
different point. Q1201
4.3.3.3 Global Service Logic
The Global Service Logic can be defined as the “glue”
that defines the order in which SIBs will be chained
together to accomplish services. Each instance of global
service logic is (potentially) unique to each individual
call, but uses common elements, comprising specifically:
BCP interaction point (POI and POR); SIBs; logical
connections between SIBs, and between SIBs and BCP
interaction points; input and output data parameters,
service support data and call instance data defined for
each SIB. Q1201 The GSL will then chain together these
elements (SIBs) to provide a specific service.
4.3.3.4 Relating the GFP to the DFP
This section describes the mapping of the elements of the
Global Functional Plane to the Distributed Functional
Plane. Functions in the GFP are distributed to Functional
Entities in the DFP. These FEs are related by information
flows, which are use to send information between FEs.
Table -7 shows the CS1 SIBs and indicates the FEs
involved for each SIB. Q1201
Functional Entities
SIB SSF/SCF SCF SRF SDF
Algorithm
Charge
Compare
Distribution
Limit
Log Call
Information
Queue
Screen
Service Data
Management
Status
notification
Translate
User
Interaction
Verify
Basic Call
Process
Table -7. Relating the GFP to the DFP.
4.3.4 Service Plane
The Service Plane (SP) is of primary interest to service
users and providers. It describes services and Service
Features from a user perspective, independent of how the
service is implemented or provisioned in the network.
Garra93
The Service Plane illustrates that IN supported services
can be described to the end user or subscriber by means
of a set of generic blocks called Service Features. A
service is a stand-alone commercial offering,
characterized by one or more core Service Features, and
can be optionally enhanced by other Service Features.
Q1201
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The Service Plane represents an exclusively service-
oriented view. This view contains no information
whatsoever regarding the implementation of the services
in the network (for instance, an IN type of
implementation is invisible). All that is perceived is the
network’s service-related behaviour as seen, for example,
by a service user. Q1201 In other words, the Service
Plane provides users and service providers a
implementation-independent architecture.
4.3.4.1 Service Features
The services are constructed of Services Features. A
Service Feature is a specific aspect of a service that can
also be used in conjuntion with other services/Service
Features as a part of commercial offering. It is either a
core part of a service or an optional part offered as an
enhancement to a service Q1201 (Table -8).
* Automatic Call Back(ACB)
Closed User Group(CUG)
* Call Hold withAnnouncement (CHA)
Customer ProfileManagement (CPM)
* Call Transfer (TRA) Customized RecordedAnnouncement (CRA)
* Call Waiting (CW) Customized Ringing(CRG)
* Consultation Calling(COC)
Follow-Me Diversion(FMD)
* Meet-Me Conference(MMC)
Mass Calling (MAS)
* Multi-Way Calling(MWC)
Originating CallScreening (OCS)
ABbreviated Dialing(ABD)
Off-Net Access (OFA)
Attendant (ATT) Off-Net Calling (ONC)
Authentication (AUTC) One Number (ONE)
Authorization Code(AUTZ)
Origin DependentRouting (ODR)
Call Distribution (CD) Originating UserPrompter (OUP)
Call Hold withAnnouncement (CHA)
Personal Numbering(PN)
Call Forwarding (CF) Premium Charging(PRMC)
Call Forwarding inBY/DA (CFC)
Private Numbering Plan(PNP)
Call Gapping (GAP) Reverse Charging(REVC)
Call Limiter (LIM) Split Charging (SPLC)
Call Logging (LOG) Terminating CallScreening (TCS)
Call Queueing (QUE) Time Dependent Routing(TDR)
Note: The service indicated with a * may only be partially
supported in CS1, because they require capabilities
beyond those of type A services.
Table -8. Set of Benchmark IN CS1 Service Features.
So, the services are comprised of one or more Service
Features. A Service Feature is the smallest part of a
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service that can be perceived by the service user. These
SFs can also be used as building blocks in the
specification and design of new, more complex services.
SFs are are comprised of one or more SIBs which are
described in the Global Functional Plane. All individual
telecommunication services identified in the Service
Plane should be described as seen from the user’s
viewpoint without reference how the services are
implemented in the network (for example, how the
Physical Plane looks like) Q1201. The Service Features
are described in detail in the next chapter.
4.3.4.2 Description of CS1 Service Features
The CS1 Service Features are described in [Q1211] as
follows:
Abbreviated Dialling (ABD)
Description No.1
This feature allows the definition of abbreviated dialling
numbers with a VPN. For the users of the VPN, the abbreviated
dialling numbers are not subjected to call restrictions, e.g., a VPN
user may not be allowed to access the Off-net Calling service
feature but can reach an off-net number via this feature.
Description No. 2
This feature allows the definition of abbreviated dialling digit
sequences to represent the actual dialling digit sequence, i.e., a two
digit sequence may represent a complete dialling sequence for a
private or public numbering plan.
Description No. 3
This service feature is an originating line feature that allows
business subscribers to dial others in their company using a short
numbering, even if the calling user's line and the called user's line
are served by different switches.
Attendant (ATT)
This service feature allows VPN users to access an attendant
position within the VPN for providing VPN service information
(e.g., VPN numbers). The attendant(s) can be accessed by dialling a
special access code.
Authentication (AUTC)
This service feature allows for the verification that a user is
allowed to exercise certain options in a telephone network. In other
words, the request made by the user is authentic and should be
granted.
Authorization Code (AUTZ)
This service feature allows a VPN user to override calling
restrictions of the VPN station from which the call is made.
Different sets of calling privileges can be assigned to different
authorization codes and a given authorization code can be shared
by multiple users.
Automatic Call Back (ACB)
This service feature allows the called party to automatically
call back the calling party of the last call directed to the called
party.
Call Distribution (CD)
This service feature allows the served user to specify the
percentage of calls to be distributed among two or more
destinations. Other criteria may also apply to the distribution of
calls to each destination.
Call Forwarding (CF)
This service feature allows the user to have his incoming
calls addressed to another number, no matter what the called party
line status may be.
Call Forwarding on Busy/Don't answer (CFC)
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This service feature allows the called user to forward
particular calls if the called user is busy or does not answer within a
specified number of rings.
Call Gapping (GAP)
Description No. 1
This service feature allows the service provider to
automatically restrict the number of calls to be routed to the
subscriber.
Description No. 2
This service feature allows to restrict the number of calls to a
served user to prevent congestion of the network.
Call Hold with Announcement (CHA)
The Call Hold with Announcement service feature allows a
subscriber to place a call on hold with options to play music or
customized announcements to the held party.
Call Limiter (LIM)
Description No. 1
This service feature allows a served user to specify the
maximum number of simultaneous calls to a served user's
destination. If the destination is busy, the call may be routed to an
alternative destination.
Description No. 2
This service feature enables to count the sunning calls to the
subscriber and to reject all the new calls when a threshold of
simultaneous calls is reached. As an option, this threshold may be
real-time managed by the subscriber.
Associated with Call Volume Distribution or Call
Distribution, it allows the rerouting of the new calls.
Call Logging (LOG)
This service feature allows for a record to be prepared each
time that a call is received to a specified telephone number.
Call Queueing (QUE)
Description No. 1
This service feature allows a served user to have calls
meeting busy at the scheduled destination to be placed in a queue
and connected as soon as free condition is detected. Upon entering
the queue, the caller hears an initial announcement informing the
caller that the call will be answered when a line is available.
Description No. 2
This service feature enables the subscriber, when a call
encounters a terminating trigger such as a busy condition or a
specified number of rings to queue that call, a specific
announcement being sent to the calling party.
Call Transfer (TRA)
The Call Transfer service feature allows a subscriber to place
a call a hold and transfer the call to another location.
Call Waiting (CW)
This service feature allows the called party to receive a
notification that another party is trying to reach his number while he
is busy talking to another calling party.
Closed User Group (CUG)
This service feature allows the user to be a member of a set
of VPN users who are normally authorized to make and/or receive
calls only within the group. A user can belong to more than one
CUG. In this way a CUG can be defined so that certain users are
allowed wither to make calls outside the CUG, or to receive calls
from outside the CUG, or both.
Consultation Calling (COC)
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The Consultation Calling service feature allows a subscriber
to place a call on hold, in order to initiate a new call for
consultation.
Customer Profile Management (CPM)
This service feature allows the subscriber to real-time
manage his service profile, i.e., terminating destinations,
announcements to be played, call distribution, an so on.
Customized Recorded Announcement (CRA)
This service feature allows a call to be completed to a
(customized) terminating announcement instead of a subscriber
line. The served user may define different announcements for
unsuccessful call completions due to different reasons (e.g., caller
outside business hours, all lines are busy).
Customized ringing (CRG)
This service feature allows the subscriber to allocate a
distinctive ringing to a list of calling parties.
Destinating User Prompter (DUP)
This service feature enables to prompt the called party with a
specific announcement. Such an announcement may ask the called
party to enter an extra numbering, e.g., through Dual-Tone Multi-
Frequency (DTMF), or a voice instruction that can be used by the
service logic to continue to process the call.
Follow-Me Diversion (FMD)
Description No. 1
This service feature allows a VPN user to change the routing
number of his/her VPN code via a DTMF phone. The updated
number can be another VPN code or a PSTN number.
Description No. 2
With this service feature, a user may register for incoming
calls to any terminal access. When registered, all incoming calls to
the user will be presented to this terminal access. A registration for
incoming calls will cancel any previous registration. Several users
may register for incoming calls to the same terminal access
simultaneously. The user may also explicitly de register for
incoming calls.
Mass Calling (MAS)
This service feature allows processing of huge numbers of
incoming calls. generated by broadcasted advertisings or games.
Meet-Me Conference (MMC)
This service feature allows the user to reserve a conference
resource for making a multi-party call. indicating the date, time, and
conference duration. At the specified date and time, each participant
in the conference has to dial a designated number which has been
assigned to the reserved conference resource, in order to have
access to that resource, and therefore, the conference.
Multiway Calling (MWC)
This service feature allows the user to establish multiple,
simultaneous telephone calls with other parties.
Off-Net Access (OFA)
This service feature allows a VPN user to access his or her
VPN from any non-VPN station in the PSTN by using a Personal
Identification Number (PIN). Different sets of calling privileges can
be assigned to different PINs, and a given PIN can be shared by
multiple users.
Off-Net Calling (ONC)
This service feature allows the user to call outside the VPN
network. Calls from one VPN to another are also considered off-
net.
One Number (ONE)
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This feature allows a subscriber with two or more
terminating lines in any number of locations to have a single
telephone number. This allows businesses to advertise just one
telephone number throughout their market area and to maintain
their operations in different locations to maximize efficiency. The
subscriber can specify which calls are to be terminated on which
terminating lines based on the area the calls originate.
Origin Dependent Routing (ODR)
This service feature enables the subscriber to accept or reject
a call, and in case of acceptance, to route this call, according to the
calling party geographical location. This service feature allows the
served user to specify the destination installation(s) according to the
geographical area from which the call was originated.
Originating Call screening (OCS)
This service feature allows the served user to bar calls from
certain areas based on the District Code of the area from which the
call is originated.
Originating User Prompter (OUP)
Description No. 1
This service feature allows a served user to provide an
announcement which will request the caller to enter a digit or series
of digits via a Dual-Tone Multi-Frequency (DTMF) phone or
generator. The collected digits will provide additional information
that can be used for direct routing or as a security check during call
processing.
Description No. 2
This service feature enables to prompt the calling party with
a specific announcement. Such an announcement may ask the
calling party to enter an extra numbering (e.g., through DTMF) or a
voice instruction that can be used by the service logic to continue to
process the call.
Personal Numbering (PN)
This service feature supports a UPT number that uniquely
identifies each UPT user and is used by the caller to reach that UPT
user. A UPT user may have more than one UPT number for
different applications (e.g., a business UPT number for business
calls and a private UPT number for private calls), however, a UPT
user will have only one UPT number per charging account.
Premium Charging (PRMC)
This service feature allows for the pay back of the part of the
cost of a call to the called party, when he is considered as a value
added service provider.
Private Numbering Plan (PNP)
This service feature allows the subscriber to maintain a
numbering plan within his private network, which is separate from
the public numbering plan.
Reverse Charging (REVC)
This service feature allows the service subscriber <(e.g.,
freephone) to accept to receive calls at its expense and be charged
for the entire cost of the call.
Split Charging (SPLC)
This service feature allows for the separation of charges for a
specific call, the calling and called party each being charged for one
part of the call.
Description No. 1
This service feature enables the subscriber to accept or reject
a call, and in case of acceptance, to route this call, according to the
time,
Description No. 2
This service feature allows the-served user to apply different
call treatments based on time of day, day of week, day of
year, holiday, etc.
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4.3.4.3 IN service modelling
The idea of IN architecture, especially the Service Plane
architecture, is to allow customers to make services for
his own communications needs with Service Features or
may combine a number of services together. Perhaps the
user want to make services with additional capabilities,
use the combination as a means to providing
communications to other parties.
In recommendation Q.1211 a the following services have
been described for the use of IN Capability Set 1
Intelligent Network (Table 4-9):
Abbreviated Dialling ABD
Account Card Calling ACC
Automatic Alternative Billing AAB
Call Distribution CD
Call Forwarding CF
Call Rerouting Distribution CRD
* Completion of Call to Busy Subscriber CCBS
* Conference Calling CON
Credit Card Calling CCC
Destination Call Routing DCR
Follow-Me Diversion FMD
Freephone FPH
Malicious Call Identification MCI
Mass Calling MAS
Originating Call Screening OCS
Premium Rate PRM
Security Screening SEC
Selective Call Forward on Busy/Don't Answer SCF
Split Charging SPL
Televoting VOT
Terminating Call Screening TCS
Universal Access Number UAN
Universal Personal Telecommunications UPT
User-Defined Routing UDR
Virtual Private Network VPN
Note: The service indicated with a * may only be partially
supported in CS1, because they require capabilities
beyond those of type A services.
Table 4-9. IN CS1 Services
Let us consider the following basic servces in detail:
Credit Card Calling (CCC), Virtual Private Network
(VPN) and Universal Personal Telecommunications
(UPT). These services are mapped to service features
according to Table 4-10 [Q1211].
CCC VPN UPT
ABD o oATTC oAUTZ C o CAUT oCD oLOG o o oQUE oTRA oCUG oCOC oCPM o oCRA o oCRG oDUP oFMD o COFA oONC oOUP C o oPN CPNP CSPLC CTDR o o
C= Core Service Feature
o = Optional Service Feature
Table 4-10. Service Mappings
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4.3.4.4 Credit Card Calling
The recommendation Q.1211 describes CCC as follows
Q1201:
1) The CCC service allows subscribers to place calls
from any normal access interface to any destination
number and have the cost of those calls charged to
the account specified by the CCC number.
2) The service allows the caller to be automatically
charged on a bank card account, for any type of
outgoing call. The caller has to dial his card number
and a PIN (Personal Identification Number), then
the called number. As an option forward calls may
be allowed, without dialling again card number and
PIN
4.3.4.5 Virtual Private Network
The private networks allow users to access remote
applications that are run by other users or, more
frequently, by the network operator itself. The VPN
service is based on the public telecommunications
networks that it uses to contruct the service. CCITT
describes VPN service as follows:
1) This service permits to build a private network by
using the public network resources. The subscriber’s
lines, connected on different network switches,
constitute a virtual PABX, including a number of
PABX capabilities, such as Private Numbering Plan,
call transfer, call hold, and so on.
As an option, to each private user, either a class of
service or specific rights and privileges may be
attributed. As another option, a private user may
access his private network from any point in the
network keeping, after authentication, his class of
service or his specific rights and privileges.
2) This service permits the use of public network
resources to provide private network capabilities
without necessarily using dedicated network
resources. The subscriber’s lines, connected to
different network switches, constitues a virtual
private network that may include private network
capabilities, such as dialling restrictions, Private
Numbering Plan (PNP), holl, call transfer, and so
on.
A PNP may provide a group of users the capability
to place call by using digit sequences having
different structures and meaning than provided by
the public numbering plan, or PNP may utilize the
public numbering plan’s digit sequences, structures
and meaning.
3) VPN allows a subscriber to define and use a
PNNP for communication across one or more
networks between nominated user access interfaces.
A PNP provides a group of users the capability to
place calls by using digit sequences having different
structures and meanings than provided by the public
numbering plan.
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4.3.4.6 Universal Personal Telecommunications
In fixed telecommunications networks, subscribers are
associated with the Network Access Point of the terminal,
the point of attachement (network access or line
identification). In mobile telecommunication networks,
subscribers can move with their terminal and they are
associated with the terminal in use (terminal
identification). Vande92 The subscriber is then charged
with the use of a personal identification number. CCITT
describes UPT service as follows:
1) UPT is a mobility service which enables
subscribers to make use of telecommunications
services on the basis of a unique Personal
Telecommunications Number (PTN) across multiple
networks at any network access. The PTN will be
translated to an appropriate destination number for
routing based on the capabilities subscribed to by
each Service Subscriber (SS).
2) This service provides personal mobility by
enabling a user to initiate any type of service and
receive any type of call on the basis of a unique and
personal network-independent number, across
multiple networks, at any user-network access
(fixed, movable or mobile), irrespective of
geographic location, limited only by terminal and
network capabilities.
4.4 The IN-structured network
The IN concept is an extension of, rather than a
replacement for, traditional service control. Since an IN
primarily affects only the internal service processing of
switching systems, it should have little influence on the
signalling procedures of a traditional network. Therefore,
we can place intelligent nodes in existing networks
without affectting traditional network operations or
capabilities. Wyatt91
The Intelligent Network consists of integrated hardware
and software distributed throughout the service providers
network. Thanks to the new technologies, service
providers will be able to create their own services.
Nerys91 Compared to the convenient
telecommunications network architecture, IN forms an
excellent and fast way of introducing services.
IN promises to change the way vendors, telephone
companies, and customers run their businesses and work
with one another. Nerys91 Today, vendors develop a
product that delivers a certain service, then sell it to
telecommunications operators. With IN, vendors will
develop software “building blocks” Nerys91, then deliver
these to telephone companies who assemble them to
create new services.
4.4.1 SCE
The Service Creation Environment capability of IN
enables effective service creation. Service Creation
Environments enable network and service providers to
create new revenue-generating services that are
independent of equipment vendor’s deployment
schedules. Many administrations are asking vendors of IN
equipment to provide them with Service Creation
Environment capabilities. This is also true of large service
subscribers, who prefer to control the operation of their
IN-based services. In the current Service Creation
Environment, service subscribers can control services
using existing capabilities or modifying parameters
within these capabilities. Current Service Creation
Environments are user friendly and support updates of
service control points and service circuit nodes. The next
generation of Service Creation Environment will also
support updates of intelligent peripherals and Adjuncts.
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Because SIBs are being defined for the IN, it is now
possible to develop a Service Creation Environment
platform to support new services and direct them to
appropriate Physical Entities. In addition, new SCEs must
provide extensive validations for new IN-based services
so they do not have an adverse effect on the overall
operation of the network or the subscribers services.
Wyatt91
The service designers are staff members of the provider’s
company. They have to create new services by definite
and unambiguous descriptions. Such descriptions are
called Service Logic Programs (SLP). After deployment
of a new service in the network, one can buy or subscribe
to such a service. Abram92
The services are determined by single Service Features.
Following the ETSI framework this should be reflected in
the service representation: each SLP should be composed
from SIBs. Abram92 The interface for composition of
new services may differ. The interface might be an
advanced specification language for the construction of
SIBs and their interfaces/(inputs and outputs). However,
it is possible to build a Graphical User Interface (GUI) on
the top of the specification language and by so ease and
speed up the introduction of new IN services.
4.4.2 The function of IN
The SSP and SCP communicate via CCITT No.7
signalling links using the services of the TCAP, SCCP
and MTP. M3010 However, at the top of this protocol
stack is the IN Application Protocol (INAP).
Figure 4-14 shows how network functions can be grouped
in a physical entity. For example, we can package the
Service Resource Function in a Service Switching Point,
Service Circuit Node, or Intelligent Peripheral, based on
traffic or customer demands. Similarly the Service
Control Function can reside in the service control point,
service circuit node, or the service switching point
Wyatt91 In the middle, the signalling network performs
the signalling transfer function.
Figure 4-14. Physical mapping of IN functions.Wyatt91
With the above capabilities a description of how IN really
functions is made. An example of the Green Number
Service (GNS or freephone) is shown here.
A service user dials the number, such as 800-beginning.
While translating the number the local exchange detects a
trigger in the SSP database telling it that this 800 number
(in this example 800-NXX-7800) is a pseudo-number
which must be translated Ambro89 by an SCP. The 800-
based numbers are usually known as IN numbers. The
local exchange (SSP) sends a TCAP message (containing
the number dialled and other information) over the SS7
network to an SCP. The SCP uses the 800 number to
access a database containing the 800 number’s
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corresponding directory number (Figure 4-15). (This
number does not have to be static, but it could depend on
factors like day, time of day, origination, and so on).
After accessing the database, the SCP sends the directory
number (in this example 305-NXX-8800) to the local
exchange in another TCAP message. The local exchange
uses the directory number to execute translation and
routing to the subscriber called. .
Figure 4-15. IN-based Green Number Service.
This principles of trigger detection and database dialog
are the basis of all proposed IN services. Ambro89 The
above example showed also the flexibility of Intelligent
Network architecture. If new 800 numbers are added,
updating need only be done in the SCP database. Also the
possibility of mobility shows that IN-like architecture is
quite developed and can handle also the future needs.
The task of a Service Management Station is to manage
the IN-services. In the above example the SMS could
have keeped track of the charging of the service usage.
The service user would not have been charged because of
the freephone capability. Instead, the service would have
been charged and provided with a charging report from
the SMS.
4.4.3 IN Application Protocol
The IN Application Protocol (INAP) is intended to be
used between the following four functions: SSF, SCF,
SDF and SRF. The INAP in CS1 is ment to be using the
SS7 protocol stack, but it does not imply that only this
signalling protocol should be used. Q1201
Figure 4-16. INAP Protocol Architecture.
The INAP protocol architecture is based on the OSI
Application Layer Structure (Figure 4-16). A physical
entity has either single interactions or multiple co-
ordinated (not discussed here) interactions with other
physical entities. The Single Asociation Control Function
provides a co-ordination function using Application
Service Elements (ASEs), which includes the ordering of
operations supported by ASE’s (based on the order of
received primitives) [Q1218]. The SAO represent the
SACF plus a set of ASE’s to be used over a single
interaction between a pair of Physical Entities. If there
were need for multiple interactions, the use of MACF
(Multiple Association Control Function) would be
acceptable. In this case, MACF would provide a co-
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ordinating function among several SAO’s, each of which
interacts with an SAO in a remote PE. Q1201
Figure 4-17. Operation description.
Each ASE supports one or more operations. Information
flows of [Q1214] are in principle mapped one to one with
operations. For example, the operations corresponding to
the information flows of the Originating BCSM for CS1
(Figure 4-8) are the following:
- Origination Attempt Authorized
- Collect Information
- Collected Information
- Analyze Information
- Analyzed Information
- Route Select Failure
- OCalled party Busy
- O_No Answer
- ODisconnect
- OAnswer
- O_Mid Call
Description of each operation is tied with the action of
corresponding FE modelling. Each operation is specified
using the operation macro described in Figure 4-17. The
use of Application Context (AC) negotiation mechanism
allows the two communicating entities to identify exactly
what their capabilities are and also what the capabilities
required on the interface should be. This should be used
to allow evolution through Capability Sets. If the
indication of a specific application context is not
supported by a pair of communicating FE’s, some
mechanism to pre-arrange the context must be supported.
Q1201
In the CCITT New Recommendation Q.1218 the INAP
and TCAP messages are specified using the Abstract
Syntax Notation One (ASN.1). The encoding rules which
are applicable to the defined abstract syntax are the Basic
Encoding Rules (BER).
Also an another IN Application layer protocol is available
there. This application layer protocol handles and
manages the mobility of users and is called the Mobile
Application Part (MAP). The MAP is not discussed
further in this paper.
4.5 Personal Communications Services
PCS (Personal Communications Services) is an important
area of Intelligent Networks. The Service Control Points
maintains the Home Location Register (HLR), which is
the home database for mobile services user, while the
local exchange, serving as a Service Switching Point,
maintains the Mobile Switching Center and visitor
Location Register. Using wireless or wire-line terminals,
subscribers have access to the IN and Personal
Communications Services.
Mobile services has been defined, for example, by ETSI’s
GSM group. The GSM architecture consists of a Home
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Location Register, the Equipment Identification Register
(EIR), and the Authentication Center (AUC), all of which
can be maintained at a central node in the network. The
central node’s master file contains the wireless
customer’s records. Local records for wireless customers
are maintained at the Visitor Location Register (VLR).
The VLR information can be located in the Mobile
Switching Center (MSC) or in the adjunct. Mobility
services have strong synergies with evolving IN
architecture. An IN control structure offers a robust
platform to support PCS applications. Many of the
conceptual model requirements for the IN apply to PCS.
Integrating PCS services on an IN platform potentiallly
reduces an administration’s operations, maintenance, and
training costs. In addition, we can provide many new
services for PCS using IN service features. Wyatt91
From an IN architectural perspective, we can view
wireless access as a technology (such as ISDN or
Broadband ISDN) that service subscribers can use to
access the network. This network can be fully integrated
with the local exchanges or provided as an overlay
architecture. The IN can flexibly separate call and
connection control from the underlying access
infrastructure. As such, an IN platform also can support
PCS applications. From a network entity viewpoint, the
network access function is conceptually similar to a base
sation system in the mobile communications world. The
service switching functionality could be implemented in a
Mobile Switching Center, allowing that center to interact
with service control residing in other network elements
(e.g. HLR that resides in the SCP and VLR that resides in
adjuncts) Wyatt91 (Figure 4-18).
Figure 4-18. PCS applications supported by an IN.
Wyatt91
4.6 Integration of TMN and IN
IN is a generic, service-oriented architecture, intended to
be used for all kinds of services (real-time or
management) on top of call-control type services. TMN is
a generic, management-oriented architecture, intended to
be used for all kinds of management services. Obviously,
the IN and TMN architectures overlap. For instance, one
TMN application such as billing and one IN application
such as Freephone must be tightly related because
Freephone billing should be handled in a consistent way
with TMN billing. This shows that, unless both IN and
TMN architectures are made more consistent, the
interconnection of IN and TMN applications would be
difficult. It is not possible to support two independent
architectures while applications on both architectures
must interoperate. Also, IN is just one part of the whole
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network, and as such should be managed with TMN. The
integration of TMN and IN can be considered as an
evolution path to TINA Appel93 .
Figure 4-19. The TMN and IN concept. Wyatt91
Figure 4-19 shows network-related functions required for
IN architecture: the Basic telecommunications network,
Intelligent Network, and the Telecommunications
Management Network. Wyatt91
The Basic telecommunications network is commonly
known as the Public-Switched Telephone Network
(PSTN), this network controls basic telecommunications
services (for example, local and transit/toll switching,
voice and data calls) offered to a user. It detects whether
control of a call should be transferred to the IN. The
Intelligent Network manages intelligent
telecommunications services offered to a user. It includes
specialized telecommunications functions, such as
customized announcements, voice regognition,
encryption, and network reource assignments. At present,
TMN controls telecommunications support for basic
telecommunications network and IN functions. In the
future, TMN will include functions such as service
creation, service provisioning, service deployment, and
service management. Wyatt91
Both in TMN and IN, the challenge is to ensure a global
consistency of all interconnected applications, while
allowing for evolution of some applications. This shows
that while IN and TMN architecture are to be integrated,
they both must evolve towards a unified target
architecture to be more flexible. Appel93
4.6.1 Comparison of IN planes to TMN planes
The IN Conceptual Model represents different points of
view to the users, customers and operators. The TMN
planes describe, however, different management-related
aspects. The correspondence of these architectures is
shown in this section.
The Service Plane represents the service from the user’s
point of view. The TMN architecture does not directly
provide with this kind of aspects. The Global Functional
Plane represents with the service designer’s point of view
of the services. The TMN architecture does not directly
provide with aspects of Global Functional Plane.
Distributed Functional Plane represents the fucntional
parts of the IN architecture and the relations between
them. This is quite the same as the TMN architectures
Functional Architecture. The relations between DFP parts
corresponds to the TMN Informational Architecture. The
lowest layer of IN architecture corresponds straight to the
Physical Plane architecture of INCM (Figure 4-20).
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Figure 4-20. Correspondence of IN planes and TMN
architecture planes.
In order to avoid multiple definitions of management it is
possible that IN will be managed through TMN concept.
This is very well stated, because TMN has been widely
accepted as a telecommunications management concept.
4.7 Globalizing the IN
The standards and research activities for Intelligent
Networks so far have focused mostly on its provision in
one closed network, emphasizing the interaction of
exchange and service control functions Fujio93. Take the
UPT service, for example. A UPT user would move from
one location to another inside a network and also over
multiple networks, possibly with different capabilities. In
such a case, coordinated provision of the service over a
wide area is essential to guarantee UPT users with
personal mobility. Also the VPN service plays an
important role in the importance of globalization Fujio93.
IN has thus far been developed to provide various
enhanced services with proprietary technologies in many
networks. Consequently, many different implementations
of IN are now available in the world. To provide the same
level of service capabilities in different networks and in
the multivendor environment, however, standardation
activities for IN are taking place in the CCITT and
regional organizations. Fujio93
4.8 Future IN Capability Sets
The main CS1 capabilities support flexible routing,
flexible charging and flexible user interaction [Q1211].
Only limited mid-call interruption facilities are supported.
It is not expected that significant capability will be
provided within CS1 for services occurring during the
active phase of call, for multiparty or multimedia
services, for services requiring the direct manipulation of
call topology such as mobility or conference calling or
non call associated signalling as needed in mobility.
Such capabilities, as well as standards for SMF and SCEF
capabilities, are expected to be provided in CSs beyond
CS1, starting with CS2, on which work began in 1992.
Refinements of CS1 will continue during 1994. The CS2
with non-call associated signalling, SDF and management
interfaces will be available in 1995. CS3 providing
terminal mobility is to be completed in 1997.
Thus, the work beyond CS1 will provide support of
mobility, multimedia calling; support of services affecting
a call in the active phases where several subscribers may
be affected (Type B Services); standards for feature
interaction mechanisms; standards for creation,
deployment, and management of service logic; and
support for complex call topology management.
However, it seems to be so that CS2 will continue to
address only Type A services.
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Besides multimedia calls, other service examples are
advanced, networked conferencing capabilities and
possibly network resource usage reconfiguration during a
call. In order for such capabilities to be realized, the
issues identified earlier, and others, will need to be
addressed and solved. Duran92
Beyond the need to support additional capabilities for
types of services more complex than a single-ended,
single point of control category, there will be need to
specify further interfaces than was possible for CS1.
Standardization of a SLEE, in parallel with a SCE, and
standard representation for service logic and service data,
which is needed for multivendor implementability, also
will be required. Duran92
Future directions of IN include a distributed architecture
using the service-independent platform capabilities of the
IN. This platform should allow us to introduce emerging
technologies and applications transparently into the
network. Wyatt91
4.9 Current activities of IN
The Intelligent Network concept and innovation is
accepted worldwide. The early innovativions came from
the United States of America which was the first country
to introduce this kind of telecommunications network
architecture. The IN architecture and services provided by
Telcos in USA have been most advanced. The other
countries in the world are still trying to gather the gap.
The hardware manufacturers have provided the
telecommunications operating companies with IN
components. These components are as the base for
current and future IN architecture. A typical scenario of
this is the digitalization of switches in the telephone
network. The use of Common Channel Signalling System
No.7 becoming common. The software providers or
Telecommunications Operating Companies are making
software for IN components, such as SCP. Also the TMN
architecture and its implementation, and the use of TMN
in managing the Intelligent Network architecture and the
services are under development.
In Finland, the state owned Telecommunications
Operating Company (Telecom Finland Ltd) is doing
much work in the above areas. The Telecom Finland
Intelligent Network architecture has been using Bellcore
components, and the CS1 upgrade is coming shortly. The
SS7 network is ready for use and the Open SCP
architecture will become available soon. The problems
are still in the management and the service creation areas.
The independent service creation by customers that
require advanced IN capabilities will require quite a lot
time. When the integration of TMN and IN will be more
entirely accepted and TMN applications management
implemented, the problems concerning remotely creatable
and configurable services by the customer will be
solvable. For this purpose R&D co-operation with
operators and hardware and software manufacturers will
be needed.
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5. Changes in business
5.1 Technology and services
The most important trends in the area of business are the
increased use of computers in business and globalization
of the markets. The telecommunications industry can be
divided into telecommunications hardware suppliers and
the providers of telecommunications services (operators,
software houses, etc.). The development of tele-
communications business depends on changes in the
industry, changes in the telecommunications technology
and the development of telecommunications services
Martik93.
There has been several major changes in the development
of telecommunications technology. The development of
mobility and higher interconnection bandwidth between
network nodes play an essential role in the changes of
networks and their services. In the eaely
telecommunications, the most important need for the
telecommunications networks was the analogical
telephony service. Later on, at the end of 1980's, with the
use of optical fiber in the transmission systems, the
available bandwidth increased and the customer expences
decreased. Telecommunications networks are becoming
multiservice networks, as already has been specified with
ISDN, and will provide advanced services based on
mobility and broadband in addition to the digital
telephony service.
The past telecommunications technology was mainly
based on dedicated devices with nonflexible architecture.
At the time of reconfiguration of these devices several
changes had to be made to the architecture (programs and
possibly also hardware). As these changes were costly, it
was obvious that the life cycles of the services were quite
large and not much customer orientation was possible.
An example of hardware changes in telecommunications
is the cable technology. The average bandwidth of the
transmission systems seem to multiply by factor 10 in a
decade. The copper cables that were used by past
telecommmunications systems needed a lot of
replacement when runned out of capacity. The situation is
however different when optical fiber is used. Optical fiber
is a flexible transmission media that can be several times
reconfigured, because the bandwidth can be increased
only by changing the active devices that use the fiber. The
physical raw bandwidth provided by optical cables will
be far beyond reach in the near future. Optical fiber also
provides expences that are almost independent of the
bandwidth.
Figure -1. Technology transform. Martik93
Faster changes of markets have decreased the life cycle of
products. The corporations have to spend more money on
product development than before and to seek for partners
to share the expences in the product development.
[Martik93] The need for more versatile services is
obvious.
The Intelligent Network telecommunications structure
will change the market areas. As the computer prices go
down relative to the performance of the unit, the IN nodes
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and components will be mainly based on computer
architectures than dedicated electronic devices, which
was a great market area in the 'past' telecommunications
business. The selling of hardware will not be the most
important area of business in telecommunications rather
the selling of intelligent nodes, which consist of cost
effective standard hardware technology, but running a
high-technology service oriented software. So software
will propably become the largest area of business within
telecommunications. The service management area of the
IN will become an important area of business to the
service providers and operators. These things will change
the market views in computers and software.
1980 1990 2000 2010
data
speech mobile
advancedservices
personalcommunication
Figure -2. The development of the telecommunications
service business.
Today about 80% of the telecommunications services are
telephony traffic and other services, such as data
transmission and value added services, about 20% of the
turnover. It has been expected that 50% of the
telecommunications services value are telephony traffic
and the rest advanced services in the year 2010.
Martik93
The main part of the future data traffic will be produced
by the LAN’s (Local Area Network) where multimedia
(e.g. video, voice and data integration) data is transmitted.
Some of the voice traffic today will move to multimedia
data traffic between workstations. The multimedia
services that are provided by the telecommunications
networks are called internationally Advanced Services.
The voice and data traffic will integrate together with the
broadband services and Intelligent Networks. However,
the Advanced Services need broadband networks while
the mobile communications networks today do not
provide enough bandwidth for these services. That is why
these services will be first introduced at the wireless
telecommunications systems and in radio technology after
the demanded bandwidth resources are available.
The main benefits of the IN architecture are the
possibilities to improve the quantity, and to develop new
sources, of revenue. This is particularly desirable in an
environment with a high penetration of available services
per capita. For most environments, the IN will be a
stimulation or basis for revenue generation, both the short
and long term. Ambro89
5.2 Liberalization, alliances and competition
The most important trends in the area of business are the
increased use of computers in business and globalization
of the markets. Martik93 This means that the use of
telecommunications networks will be growing a lot in the
future within domestic markets and also a great deal
within international markets. The organizations need
more and more the services provided by
telecommunications networks eg. in order to
communicate with computers from one subsidiary to
another. The liberalization of telecommunications
business in several countires will increase the life cycle of
services and decrease the price that is taken from the so
called 'hardware' level services, such as telephony service
or simple data transfer service. The formation of
continental and intercontinental alliances, for example, in
Europe has driven down the prices of services in several
countries.
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The competition with telecommunications services will
certainly increase. Service providers in the past
introduced quite similar services, because the rigid
technology enabled just non-value added services and
there was hardly any tools for differentiation. Broadband
switched transmission and access by ATM leave quite
much differentiation space for the services, and the value
is transferred from the pure interconnection to the mobile,
value added and media services (Figure 5-3).
Figur
e 5-3. Value addition of services.
The prices of raw interconection service in the past were
dominant. They have decreased very rapidly in the past
couple years. Such kind of a decrease, according to my
opinion, will happen to every non-value adding
telecommunications service. They can be said to become
a 'every man's' tool. IN adds quite much value to the
telephony service and the services of it will be quite
highly-priced at the beginnning. ATM itself does not add
any value to conventional data transfer except speed, but
broadband IN itself makes possible to create fast and
effectively broadband services. (Figure 5-3). In future it
seems to be that the non-value added services become
very cheap. It could also happen that the prices would be
the same as we have for using roads, where the fees are
taken as taxes in each country. The use of
telecommunications networks fees would be perhaps per
year basis fixed costs, not per minute as variable costs as
we are used to now. Instead, the value-added services will
fill the place of former interconnection services. We are
going to pay more and more for the contents or data
inside the service than for the technology itself and the
expences that has accumulated in the technological
Research & Development period.
5.3 IN services
5.3.1 Benefits of IN
The concept of Intelligent Networks has been developed
to achieve some major goals. These are:
Rapid service introduction, which for the
operator means an ability to meet a market
window, niche market or to adapt to specific
customer requirements. This goal is targeted
for revenue growth.
Standard interfaces, which for the operator
means multi-vendor capability. This goal is
more related to cost efficiency and high profit
rather than revenue.
Flexible network architecture , which could
allow operators to configure and develop their
networks more freely to meet market
requirements, bypassing dominant vendors.
Integrated management integrating the needs
of the service management into a single logical
network management.
In business terms the above things are expected to happen
after introducing IN: Increase in revenues, through a
capability to offer new services to the customers; lower
level of investments, when standard products are
available from several sources; and decrease of
operational cost, due to the integrated management of
services and networks impacting on the number of human
resources required to operate the network.
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In reality these goals are very hard to achieve. IN is not
the answer for the management problems, nor will it
automatically generate new revenue. It can be part of the
solution, but there is much to do before these goals can be
met. Too often required enhancements in other
information systems, and redesigning of the operations
and organizational structure are neglected or at least are
not taken into account, when IN investment/introduction
is planned.
5.3.2 Cost structure
5.3.2.1 Initial cost of IN
The level of investment required for introducing IN
network concepts into the network is a relative issue. For
large international operators IN investment can normally
be justified based of a cost/benefit calculations made for
one service only. For a smaller operator IN is usually a
major investment, which may be critical to do. If IN is
introduced as a major network concept through the
network, IN will have a significant impact on the
operators on the level of the investment, which is required
for network development.
Initial IN investments/expences can be broken down as
follows:
IN element (60 - 70 % of total investment)
This includes necessary basic hardware and software
components which are required for IN, and is
around 50-60 % of total purchasing expences. Most
of this is needed for software, concentional
hardware is minor part of investment. The cost
structure of IN element consists of hardware and
basic software (20%; basic SSP including hardware
and software (typically a switch), IN application in
SSP, SCP and SMS including basic hardware and
software, and other equipment and software required
for operating IN), and IN specific software (40%;
SCP and SMS applications).
Project expences (30 - 40 % of total investment)
Project expences are higher than usual. This is due
to the complicated nature of IN concept
implementation commonly taking more resources
for integration than traditional network development
projects. The project expences can include: project
management, system specification, system
integration, system testing, and system deployment.
Integration expences (? % of total investment)
This part of expences depends on the size of IN
system, its planned level of integration with other
systems and so forth. The level of these expences in
the initial introductory phase of IN is generally
difficult to estimate. Often, integration issues such
as: integration of IN with current network
management systems and integration of IN with
current customer service systems are handled only
after the first IN application is taken into use.
It is difficult to give a formula on how to define exact
portions of these expences for IN projects. IN expences
tend to always be a specific case which is dependent on
the operators market, techical, economical and other
environmental issues. The most significant point is that
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with currently available IN products, portion of
investment which consist of standard hardware and
software components is relatively low and the major part
of the investment consists of special/tailored software and
project running expences.
5.3.2.2 Operational costs of IN
When examining operational costs, attention shall be paid
to those operational costs which are directly related to
operations and management of IN platform components,
comprising of hardware and software maintenance
charges and other operational costs.
Associated operational costs are significant portion of the
total costs. The main parts of these costs are marketing,
sales, R&D for the customer end of the product and the
costs for supporting systems.
5.3.2.3 Basic call production costs
IN services need local loop, trunk transmission and the
switching machinery in operation before IN based
revenue generation can be put into operation. The
operator/services provider have to include these expences
until it is possible to calculate the total IN call production
costs, which then have to be covered by incoming cash
flow to be able to run financially successful operation.
5.3.3 Service portfolio
IN seems to be the only vehicle, which offers operators
new tools to provide extended call handling capabilities.
The capabilities may be regarded as a basic element of
the modern products concept. IN makes it possible to add
value to basic call handling. These more flexible network
services may be packaged to suit for different market
segments relatively easily. In this respect IN has proven
to be a useful concept. However, it is not evident that IN
based services automatically generate new traffic and
revenue.
5.3.3.1 Operators capability of offering services
That in IN has made it possible to offer new services to
the customers cannot be denied. But one has to remember
that the possibility of utilizing switches as service
platforms still exists. An operator’s capability to
introduce new services, which are based on IN
technology is largely dependent on the operator’s
capability to manage the complex composition of IN
software and how an IN implementation supports the
flexible management of data in the system. It can be
questioned, if operators have made a good choice in
coming dependent of software houses, as has typically
happened, rather than switch vendors what concerns their
service development capabilities.
How capable the operators are in the services arena is
heavily dependent on the software strategy which is
adopted when decision of building IN facilities has been
made. Again in this respect operators vary largely.
5.3.3.2 Sales of service portfolio
Cannibalism still exists and this is especially common
within telecom service sector. Voice services offered by
Telco’s have not developed significantly since the 1960’s.
It can be assumed that basic demand for the utilization of
telephones has always existed. IN has facilitated in
packaging service features in new combinations. These
combinations have been developed to standard IN
services such as Premium Rate, Freephone, Calling Card,
UPT, VPN and so forth. But have these IN services
generated new revenues ? Definitely to some extent, but
all the credit can be given to the IN concept, and when
evaluating the economical impact of IN, this matter has to
be considered.
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5.3.3.3 Service development time frames
Inmaterial nature of the telecommunications service
allows better interaction with the consumers when
developing the service products compared with, for
example, manufactuing industry. In this respect, IN has
great potential. Utilization of this potential requires a
comprehensive SCE environment. Useful SCE
environments have been on the market only a short while
and unfortunately these products typically support a
restricted range of products from a single source.
Service development life cycles have shortened and there
are products available in the market, which make it
possible to take an experimential approach to service
development.
5.4 Evolution of IN capabilities at Telecom
Finland
5.4.1 Pre-IN
Telecom Finland was one of the first operators in Europe
to offer IN-type services to its customers. The first
services (Freephone, Premium Rate) were developed on
switch based solutions in mid of the 1980’s. Successful
implementation of these services was based on the
expertise Telecom Finland has in digital switching.
Through the early implementations Telecom Finland has
been able to gain a dominent position in the enhanced
services market in Finland. In this first phase services
were developed in close co-operation with the customers
of Telecom Finland. Switches were used as service
platforms to avoid unnecessary investments of IN. Some
of these early implementations are still deployed.
5.4.2 Centralized IN
Soon after the first IN implementations Telecom Finland
started to investigate potential IN concepts, which could
provide more sophisticated management and a greater
capacity for IN services. At the beginning of 1990’s
Telecom Finland made a contract to purchase a real IN
solution, which consisted of dedicated SSP, SCP and
SMS elements. At this time all the business indicators
justified investments of this size. Altogether the IN
project lasted for three years and it was a risky project
financially.
5.4.3 Special services
The start of open competition put pressure on Telecom
Finland to speed up the development of IN services. This
challenge was met with purchasing more IN capabilities
and developing competance inside Telecom Finland to
rapidly develop new services. For the special services an
additional node with SCE capabilities was purchased.
With this investment, Telecom Finland was able to reduce
time for services development down to acceptable level.
Limited new services can now be developed in days,
more sophisticated ones in months.
5.5 Distribution channels
There has been a major change in accomodities'
distribution. Here we however, refer to services.
Telecommunications organizations today and in the past
used to distribute the so called raw services via
telecommunications networks. They created their revenue
according to the amount of telephony calls were dialled in
their network, where they served as operators. What is
important to notice is that the service provider actually
was located in the different place than the paying
customer. Telecommunications can such gain quite
effective and cheap distribution channel, if the prices of
raw data transfer goes noticeably down.
The same approach as above can also be brought to the
broadband services eg. high-speed image transfer. Think
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about the following medical situation: a nurse is taking
photos of a patient. The nurse itself does not have the
skills or knowledge to appraise the condition of the
patient. She could use a doctor who is residing 100
kilometres away from the medical centre to give some
advice. The only thing is that the doctor would have to
take a flight to that centre (expensive) or the nurse would
have to send it by post (too slow). One solution for this
problem, in the future, would be the use of high-speed
data transfer to transfer the digitized images to the
organization, where the doctor actually works. The
broadband networks would also enable some
videotelephony calls or videoconferencing with the
experts that are more aware of the problem.
The above was just an example to describe the changes in
distribution channels. The facts that telecommunications
networks provide to telecommunications service
organizations are that: their services are better available
for customer (any time of day and in the future anywhere
globally), they are fast reachable (customers don't have to
wait eg. for the slow post service) and they are quite
cheap reachable or at least the variable expences that are
included in the service usage (the same can not be said of
the fixed part eg. the equipment to have broadband data
transfer and the service platforms). This kind of
distribution channel stimulates the professionals on the
market to market new types of services and this way to
have an effect to the price that the customer needs to pay.
The problems today are that the technology is not yet
quite advanced in order to make these kinds of services
possible in massive or wanted scale. Some pilot research
projects have been made or are being made on these
areas, but any broadband services are actually
implemented yet.
5.6 Changes in enterprises
The major changes of organizational structures in this
century will also be reflected in network and service
operator structures (Figure 5-4). At the beginning of the
20th century there was emphasis in the production of raw
materials and agriculture. Then the society became more
industrialized and the industrial organizations grew up to
vertically integrated firms. The large scale mass
production and product differentiation were the main
paradigms since the 1930's. The growth was sought from
diversification to new synergic areas.
special
basic
1900-1950Vertical Integration
1970:Diversification
Basic
1990:Networks of Enterprises
Figure 5-4. Changes in enterprise structure.
The present and future organizations are more like
networks of enterprises, where the main organization
itself is broken up into smaller units and they utilize
external firms as subcontractors and distribution channels.
This kind of business structure is typically found in many
design and high-technology industries. The organizations
have to focus into their strongest areas to be able to be
competitive. Since there must be both cost advantage of
mass production and market based differentiation present,
the areas outside the company focus must be obtained
from partners, who provide their part of the final concept.
So, the value obtained by the end user is combined from
the different value attributes provided by a network of
several companies.
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The telecommunications industry is based on high-
technology development and also much subcontracting
are used nowadays. The number of subcontractors used
will increase in the future. An telecommunications
service organization could actually be like the following:
It uses networks operators to provide digital access to the
customers and large service and media providers as
contractors to produce the services. It rents the needed
physical computer and network equipments itself and
uses own computer programmer's to program the wanted
logic for customer and service management. The
organization itself would just co-ordinate and design the
service provision and distribution and keep the functions
alive. The structure would be a network of enterprises,
each enterprise specialising on its most qualified areas.
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6. Broadband intelligence andmedia
6.1 Broadband networks
The emergence of optical transmission technique has
provided more higher transfer rates and reliable transfer
for the networks. The bit error propability has moved
approximately from 10 6− in the copper based signalling
technique to 10 9− and even better in the optical
transmission technique. This has started projects on
defining new applications based on optical transmission
media.
Just a few years ago the telecommunications systems
used mainly PDH technique in the transmission systems.
This technique did not enable high-speed data transfer
and would have caused several problems when used in
high-speed data transmission. With CCITT's new SDH
technique these problems can be bypassed. SDH
technique provides a synchronous digital data transfer
based on optical transmission media, where one bit can be
exactly pointed at the destination station from the media
stream and also in the switches between the link. The
switches can then process the frames in SDH at real-time
(In practice with only a few bits delay) and forward them.
This is one reason why SDH technique is used in many
broadband networks at the physical layer of their protocol
stacks.
6.1.1 B-ISDN
B-ISDN (Broadband Integrated Services Digital
Network) is a concept specified by CCITT. The lower
parts of the B-ISDN reference model layers are
standardized, but the user and network management parts
of the B-ISDN appear to be on the whole at the draft
stage. More innotation on the standardization work has
been shown from the ATM Forum. The ATM Forum
consists of members of several existing enterprises in the
area of telecommunications and regional telephony
operators.
Figure -1. B-ISDN reference model.
B-ISDN concept is based on the integration of different
kind of services. The reference model describes several
layers: physical, ATM, AAL (ATM Adaption Layer)
layers and the upper layer protocols. B-ISDN uses out-of-
band signalling to separate the user and signalling data.
6.1.1.1 Physical layer
The physical layer involves the packetization of the user
data into the physical medium slots. In Europe, CCITT’s
SDH (Synchronous Digital Hierarchy) technique is used,
while ANSI’s (American National Standards Institute)
SONET (Synchronous Optical NETwork) is used in the
USA. However, SDH and SONET do not differentiate by
their contents. The transmission technique is based on
synchronous data transfer in optical cable and several
transmission speeds are specified. SONET describes the
different speed levels as OC-x’s (Optical Carrier level at
x) while STM-x’s (Synchronous Transport Module) are
specified in SDH. These levels are multipliants of the
basic level OC-1 (51.840 Mbit/s) and STM-1 (155.520
Mbit/s).
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Today the level OC-3 is used and ATM equipments for
the speed of approximately 622 Mbit/s (OC-12) will be
introduced in the very near future (some switches already
available in 1994). The gigabit transmission speeds, such
as 2.488 Gbit/s (OC-48), will first be used in backbone
networks and SONET standards are scalable up to almost
10 Gbit/s transmission rates, which are expected to be in
use in the future.
6.1.1.2 ATM layer
ATM is defined in the standard I.121 and is based on the
fast packet switching technique. It mixes the good effects
of the conventional circuit switching and the packet
switching tehcnique used in data packet networks. This
new technique is called cell transmission. Cell
transmission uses short, fixed length packets and in ATM
the cell structure of 5 bytes of header and 48 bytes of data
is used. While ATM relies on the optical transmission
technique, only a cheksum that notices one sequentially
appearing error is provided for the header part. The use of
such short cells enable shorter delays in the network
switching nodes than the use of variable length long
packets. And, so can the applications of the ATM
networks get smaller changes in the arrival times between
the packets at the destination (known as jitter). This is
quite obvious in the use of isochronous data streams
produced by applications, such as video conferencing
(realtime digitized uncompressed images + voice). So the
task of ATM layer is to split the upper layer data in to
such 48 byte cells and add the needed 5 bytes in the
header, which include the destination address and some
other functionalities not described in this paper.
Figure -2. ATM cell structure.
6.1.1.3 ATM Adaption Layer
AAL provides with more advanced functionalities than
ATM layer to the user. For instance, a checksum is
provided for the whole ATM packet.
Inserting payload data into the 48-byte information field
of the ATM cell is accomplished by the ATM Adaption
Layer. The AAL is what gives ATM the flexibility to
carry entirely different types of services within the same
frame format. It is important to understand that the AAL
is not a network process but instead is performed by the
network terminating equipment. Thus, the network’s task
is only to route the cell from one point to another,
depending on its header information. It should be noted
that up to four bytes may be used by the adaptation
process itself with some AAL types, leaving 44 bytes for
payload information. Forum93
Several AAL layers have been standardized: CBR
(Constant Bit Rate) services, connection-oriented and
connectionless VBR (Variable Data Transfer) data
transfer, and Simple and Efficient Adaptation Layer
(SEAL). Forum93
There are very widely spread protocol architectures, such
as TCP/IP, in use today. The existing UDP (User
Datagram Protocol), TCP (Transmission Control
Protocol) and the newest RTP (Real-time Transport
Protocol) (under research in the Internet organization)
will not be thrown away until a very advanced solution is
readily available. One candidate solution would be the
HSTP (High-Speed Transfer Protocol) that is provided by
CCITT, but it has just received the draft stage. Some
major conclusions can be drawn from the charasteristics
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of HSTP. It uses flexible flow control methods eg.
different type of flow control method to different
situation, it supports quite efficiently parallel
implementation of the protocol itself and it is in several
ways optimized to high-speed data transfer. So, it is likely
that AAL will not be used at the beginning of ATM era.
AAL will be used when there are sophisticated user
interfaces available for AAL data transfer.
6.1.1.3.1CBR
CBR is a service is type 1. (AAL1) service of AAL. It
handles traffic where there is strong timing relation
between the source and the destination. Examples include
PCM-encoded voice traffic, contant bit rate video, and the
emulation of public network ciruits (e.g. the transport for
E1 links).
6.1.1.3.2VBR
VBR defines the AAL3/4 service. It is fairly complex
layer that can handle VBR (i.e. bursty) data both with and
without pre-establishing an ATM link. Examples for the
connection-oriented type include large file transfers like
CAD files or data backup. The connectionless type is
intended for short, highly bursty transfers as might be
generated by LANs.
6.1.1.3.3SEAL
SEAL defines the AAL5 service. It may be looked at as a
simplified version of AAL3/4 that is designed to meet the
requirements of local, high-speed LAN implementations.
AAL5 is intended for connectionless or connection-
oriented VBR services.
6.1.1.4 Control plane
This plane has a layered structure and perform the call
control and connection control functions. It deals with the
signalling necessary to set up, supervise and release calls
and connections. I321 In other words, ATM uses
signalling protcol to make up the virtual path from the
source to the destination. It is the same way the
conventional telecommunications network, such as
telephony network, handles the connection opening.
Every component (ATM switches) along the virtual path
is indicated of the connection opening so no enhanced
routing has to be done at the network nodes.
6.1.1.5 Management of the B-ISDN architecture
This part of B-ISDN are has not yet been standardized.
CCITT has made some approaches to B-ISDN
management point of view.
The management plane provides two types of functions,
namely Layer Management and Plane Management
functions. The Plane Management performs management
functions related to a system as a whole and provides co-
ordination between all the planes. Plane Management has
no layered structure. Layer Management performs
management functions (e.g. meta-signalling) relating to
resources and parameters residing in its protocol entities.
Layer Management handles the Operation And
Maintenance (OAM) information flows specific layer
concerned. I321
6.1.2 ATM networks
The ATM networks will be based on a hierarchial basis,
such as the conventional telecommunications networks.
The layout of the architecture seems to be like the normal
telephony network, but the technology is able to provide
with some very enhanced services not applicable in the
conventional telephony network.
A very much simplified example for the structure of an
ATM network is shown here. (Figure ) It is important to
understand that the various UNI (User-to-Network
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Interface) and NNI (Network-to-Node Interface)
connections could be carried via different physical media,
such as the existing Plesiochronous Digital Hierarchy
(PDH) layers or the new SDH. Several standards have
been defined on how to interface the physical layers, and
work is continuing to specify additional physical layers to
be used to transport ATM cells. Forum93 (Figure 6-3)
ATMswitch
ATMswitch
ATMswitch
Figure -3. ATM network architecture.
6.1.2.1 Virtual Channels and Virtual Paths
The concepts Virtual Channel (VC) and Virtual Path (VP)
are affected when ATM cells are transported through the
entire network. (Figure 6-4)
A VC is mostly known as VCC (Virtual Channel
Connection). A VCC is set up between any source and
any destination in the ATM network, regardless of the
way it is being routed across the network. Fundamentally,
ATM is a connection-oriented technology. The way the
network sets up the connection is therefore by means of
signalling, i.e. by transmitting a set-up request, which
passes across the network to the destination. If the
destination agrees to form a connection, the VCC is set
up between the two end-systems. A mapping is defined
between the Virtual Channel Identifiers (VCI)/ Virtual
Path Identifiers (VPI) of both UNIs, and between the
appropriate input link and the corresponding output link
of all intermediate switches. Forum93
A VCC is a connection between two communicating
ATM end entities. It may consist of a concatenation of
several ATM VC links. All communication proceeds
along this same VCC which preserves cell sequence and
provides a certain Quality Of Service (QOS). Note that
the Virtual Channel Identifier in the ATM cell header is
assigned per network entity-to-entity link, i.e. it may
change across the network within the same Forum93
VCC.
VC1
VC2
VC3
VC4
VC5
VC6
VC7
VC1
VC2
VC3
VC4
VC5
VC6
VC7
VC1
VC2
VC3
VC4
VC5
VC6
VC7
VC1
VC2
VC3
VC4
VC5
VC6
VC7
VC1
VC2
VC3
VC4
VC5
VC6
VC7
VC1
VC2
VC3
VC4
VC5
VC6
VC7
VP1
VP2
VP1
Figure -4. Virtual Channels and Virtual Paths.
A Virtual Path groups VCs carried between two ATM
entities and may also involve many ATM VP links. The
VCs associated with a VP are globally switched without
unbundling or processing the individual VC in any way
or changing their VCI numbers. Thus, the cell sequence
of each VC is still preserved, and the QOS of the VP
depends on that of its most demanding VC. As the cell
address mechanism uses both the VCI and the VPI,
different VPs may also use the same VCI without
conflict. A cell may also not be associated with any VP.
In this case, it would have a null VPI and only a unique
VCI. Forum93
By means of VCs and VPs, virtual circuits can be set up
either permanently (by using so-called ‘Permanent
Virtual Channel’ (PVC)) or on demand (‘Switched
Virtual Channel’ (SVC)). It is likely that VPs will be used
mostly between switches (i.e. across NNIs) to carry
across large numbers of virtual circuits. In any case, all
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the ATM switch has to do is to identify, on the basis of
the cell’s VPI, VCI or both, which output a received cell
needs to be routed to, and what the new VPI/VCI on this
output link is. The operation of an ATM network is
therefore very simple and inherently can scale to very
high speeds. Forum93
ATM network technique may look quite simple at the
first look. Actually what makes the ATM netowork more
complex is the network management. ATM is
connection-oriented virtual circuit network, which uses
signalling links to establish a ATM connection between
source and destinations stations. The signalling schemes
in the UNI and NNI become quite complex. What is more
complex is the management of the high-speed data
stream. The ATM network supports QoS-concept for the
users. These mechanisms come quite complex if they are
fully implemented.
6.2 Applications for the broadband networks
The explosive growth of available link bandwidth for
applications has changed and will change even more the
nature of the computer applications. The applications will
be even more parallelized, and concerning the multimedia
applications, several multimedia servers will be located in
the highly distributed network architecture.
Just a few broadband applications to mention, it is quite
sure that hundreds of them will exist in the future. (Figure
6-5) First applications could perhaps be high-quality
visual telephones that use just a slight compression
technique to pack the moving high-quality images.
Because of the large available bandwidth it is possible to
send images with no compression at all. Of course, the
normal telephony service can be provided in broadband
networks.
It is also expectable that TV companies will not just
broadcast TV programs in the future. With high-capacity
broadband networks TV corporations can then multicast
digital (such as HDTV (High Definition TeleVision))
programs to the customers. This will provide the
customers to independently of each other to subscribe TV
programs from the TV companies. The greatest advantage
for the customers will be that the charging can be done
according to watched programs eg. 'on demand basis'.
Movies on demand that is often called Video On Demand
(VOD). The solution for people not knowing how to
program their VCRs is that they don’t have to anymore;
the telecable companies - the result of the telephone and
cable company mergers - download whatever program
people want to watch. People buy or rent movies from
the infotainment service providers LAN94. The
difference between the TV multicasting is that VOD
provides a service that can unicast movies to the
customers. Both of these services belong to the category
of Pay-per-View. So, the videorent corporations no
further have to keep video cassettes in the store, but a
large store capacity of data, such as CD-ROMs (Compact
Disk-Read Only Memory), etc.
Some additional services might be provided to the
customers, such as video shopping, interactive games,
education, and information publishing. In videoshopping
people interact directly with the video catalogs, checking
availability and pricing with the stores’ databases.
LAN94 The network’s high-speed nature makes it
practical and close to realistic to play interactive VR
(Virtual Reality) games, which are particularly popular
and need a lot of computer capacity. In education the
high-speed networks bring classes and research materials
to people everywhere. With interactive information
publishing, you can find as little or as much information
as you want just by asking your navigation software for
help.
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Figure -5. Some broadband network applications.
Telephony This service is just the normal
telephony service via the ATM
network. It uses an
audiograbber to encode the
voice at both of the stations.
Video telephony This service is an advanced
telephony service mixed with
video. It uses the videocameras
and a videograbber to grab the
moving videoimage.
Audio On Demand This service (AOD) would act
like as listening to a
conventional CD player. The
customer requests the server
for a CD audio sample and
then the server begins sending
the digitized audio samples to
client. The service would
include PLAY and STOP
functions.
Video On Demand VOD is similar to AOD, but in
addition to voice also moving
picture is transferred. In future,
it might be competing with the
video rent business. The
service would include PLAY
and STOP functions.
Video
Conferencing
This service is almost the same
as the video telephony service,
but this needs multicasting
capabilities, where video
telephony needed only
unicasting.
Table -1. Some possible broadband services.
Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 76
7. Broadband IN
7.1 Introduction
The Intelligent Network concept now involves with
narrowband ISDN and other slow speed networks.
Broadband IN (BIN) is a concept for the use of high-
speed transmission technique in the Intelligent Network
structure. This is possible in IN because of its flexible
architecture. IN provides computer controlled
telecommunications and in B-IN, IN controls, for
example, the function of ATM switches. The standards
for the IN&B-ISDN access has not yet been introduced,
so BIN focuses just on controlling the high-speed
switches theoretically.
ATMswitch
ATMswitch
Userstation
Serviceprovider
DB DB
ATMnetworkaccess
ATMnetworkaccess
DB
DB
ATM Signallingprotocol Q.2391
Figure 7-1. The Broadband IN concept.
The Broadband IN is a concept where the Intelligent
Network structure is used to manage and control high-
speed network technologies, such as ATM switches.
(Figure 7-1) The user is accessed via a high-speed
interface, such as an ATM interface. When the user wants
to use BIN services he connects to a specified BIN
service number eg. ATM address via the ATM interface
and waits for the control unit to make the service ready
for use. If the service reach model would be as in
conventional IN, then the switching point would notice a
BIN call and forward with a message to the control unit.
However, a different vie to this is brought in the Telecom
Finland BIN project.
7.2 Telecom Finland BIN Project
Telecom Finland and Lappeenranta University of
Technology (LUT) has started on a project to research
broadband, ATM-based, Intelligent Network oriented
architecture Broadband Intelligent Network. The research
considers the future broadband multimedia services and
their designed implementation according to this
architecture. BIN has not been standardized or even
implemented yet but being now in the pilot design phase.
BIN is a name for the project, which started in march
1994 at Telecom Finland.
The objects of the project refer quite much to the
conventional narrowband IN ie. fast service introduction
and decrease the resources needed to implement
broadband services. The main objects concerning the
architecture have been centralized customer charging
techniques and multiservice offerings at single service
points. The goal of BIN of user point of view is that the
user does not have to be aware of the technical
implementation of the service used.
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Lappeenranta University of Technology and Telecom Finland 77
7.3 BIN Architecture
7.3.1 Components
BIN components are BSSs (Broadband Service
Subscriber), BSPs (Broadband Service Provider), BSCPs
(Broadband Service Control Point), BSMPs (Broadband
Service Management Point) and BSSPs (Broadband
Service Switching Point) (Figure 7-2). BSSs, BSPs and
BSCPs are connected to BSSPs, which form the ATM-
network. BSMP is connected to BSCP and is not tied to
any physical implementation technique.
BSCP
User Work-station
MIB
MIB
BSS
User service palette
Charging
User identification
Servicepalettes
BSSP
MIB
MIB
Provider Work-station
BSP MIB
Directorystructure
Icons
BSCPSL
Screen
BSSPmanagement
NTS
CC
BSMP
BSSPBSSP
BSSP
BSP identification
List of BSP:s
Iconmanager
Connect
BSP
Hyper-media
lib.
D-HDTVVOD
AOD
BSP Service Logics
Home-shop
Generic Service Logics
Iconmanager
DBDB
Multimediadata
Broadband specific Service Logics
QoSmanager
UPT
“UPT”-parameters
Iconmanager
F
igure 7-2. BIN Architecture.
Several service providers, which would use different
protocols and managing architectures, could be designed.
If done this way, every service provider should
implement their own mechanisms of charging and
managing services. One advantage of this architecture
would be quite simple interface to the end user and one
disadvantage quite complex service introduction.
Intelligent Networks have centralized service
management architecture, whereby components can be
distributed from each other. The objective of this project
is to have a centralized model, where the users (BSS)
could use services provided by BSPs and have a
centralized service management system. The BSS station
itself would be a sophisticated computer or programmable
device with appropriate resources to use the broadband
multimedia data.
BSMP contains customer identification and charging
information, a list of BSPs known to it and possibly a
customer service palette. In BSCP are the general
Service Logics (SL) also existing in conventional IN,
which can be used in several services, such as broadband
equivalents of CC (Credit Calling), NTS (Number
Translation Service ), and UPT (Universal Personal
Telecommunications). In addition, broadband services
have SLs for controlling icons and QoS (Quality of
Service) -parameters, and SL for a connection initializer.
BSS has possibly an own customer service palette, icon
manager, SL for BSCP, and a screen handler for showing
the multimedia data. In BSP lie the actual multimedia
databases (DB) and icon databases. Also the SLPs for
broadband services are located there.
7.4 BIN and IN
In conventional narrowband IN the user has a simple
interface to the network ie. either from the SSP (Service
Switching Point) or the NAP (Network Access Point ). The
highly simplified function of CS1 (Capability Set 1) IN is
that the user is connected via SSP or NAP to the SS7
(Signalling System No. 7) network, which forms the
signalling network of the IN. The user dials a phone
number, which is then generated to a message and
transferred to the nearest SSP. If the number begins with
a 0700 or 0800, SSP knows that the user chose an IN
number. In this case, SSP triggers an IN call, otherwise
Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 78
the call setup procedure is just as for a normal call. SSP
forms the intelligent part of conventional IN. SSP triggers
the IN call and forwards an INAP (Intelligent Network
Application Protocol) message to the SCP (Service
Control Point) via the SS7 network using the services of
TCAP (Transaction Capabilities Application Part). SCP
then have control on the next step eg. sends a control
message to SSP.
In BIN the function of BSCP is different from SSP and
SCP. The BSSP (Broadband Service Switching Point)
(here ATM switch) does not notice the BIN service
request and send it to the B-SCP (Broadband Service
Control Point) as it would, if the BIN would operate as a
conventional IN.
BSSP is in point of fact a simple high-speed switch
architecture eg. ATM-switch. The functions of such a
switch is to route the 53-byte cell from input end to
output end according to the Virtual Circuit Identifiers
(VCI) and Virtual Path Identifiers (VPI) and the
information that has been configured in its routing tables.
The switch is not intelligent like conventional IN switch,
because it does not trigger an IN call. It handles any data
in the cells transparently. Compared to the SS7 network's
64 Kbit/s capacity ATM-network forwards cells at a
much higher rate ie. 155 Mbit/s.
SSP solutions are mainly based on hardware solutions.
They can not be programmed as easily as computers. In
BIN however, BSSP performs all the functions needed to
create broadband services. While BSSP being simple, the
BSCP has to be quite complex. The end nodes, BSS and
BSP, are thus also quite complicated. This means that
application layer protocol BINAP is tranferred between
all the end nodes unlike in conventional IN, where INAP
is mainly used between SSP and SCP.
7.5 Broadband services categorizing
In fact the few services shown in table 7-1 are in a way
quite similar to each other. They could be grouped into
three different categories: controlled file transfer1
based
AOD and VOD, hypermedia database2
based
hypermedia library and homeshopping, and single- or
multi-party3
calls. By doing this controlling of the
services can be done in a similar way. There does not
have to be different controlling mechanisms for every
service provided. The controlling mechanism (BINAP) of
BIN services will be discussed later on.
AOD
VOD
Hypermedia
library
Homeshopping
Videotelephony
Videoconf-
erencing
Table 7-1. Some broadband services.
7.6 Functioning of BIN architecture
The main idea of BIN architecture is that the user does
not directly communicate with the service provider with
BINAP messages. BSCP, which forms the controlling
part of the BIN, processes the BINAP message sent to it,
makes statistics, and controls other points by sending
BINAP messages to them. The advantage of this kind of
architecture is that the end systems (BSS and BSP) do not
have to be as complex as the controlling systems. The
main intelligence of a service lies in BSCP and BSP,
where are the BSLs (Broadband Service Logic). BSS has
Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 79
mainly the intelligence of requesting a service and
interpretating BINAP messages sent to it.
BIN consists of two data streams: the management data
stream and multimedia data stream. BSS communicates
only with BSCP, but BSCP is responsible for
communicating with all the other components. Below the
transport layer BSS does communicate with the BSP, but
it gives upwards only data indications. (Figure 7-3)
ATM
BSCP
BSS BSP
User
Transportlayer
Transportlayer
DB
Transportlayer
Management
Data stream
Figure 7-3. Management and data stream separated.
7.6.1 Requirements of ATM network
The signalling protocol itself is not quite developed yet as
it should be in order to establish BIN architecture using
ATM. The BSS uses the ATM signalling protocol
(Q.2391) to set up the path to the destination, which is
BSCP or it could use the PVCs that are available to
BSCP. However, the BIN architecture suggests to use
BSCP to establish the path between BSP and BSS.
Q.2931 signalling protocol does not define these kind of
functions. Q.2931 UNI version 3.0 does not define a third
parties connection setup as it should be. UNI 4.0, which
should be introduced in late 1994, should contain the
third party connection setup function defined.
7.7 Course of BIN events
Let us consider the event flow of BIN events.
BIN Service Logic
Directory browsing
Icon browsing Icon activation Conn. synchron. Service logicUser identification
Icon creation
Service paletteprocess
Service activation
Charging
Figure 7-4. Course of BIN events.
7.7.1 Service request phase
User identification :
The user sends a BINAP message to BSCP and gives
sufficient identification information of him/herself. The
user has to know the ATM-address (CCITT NSAP
(Network Service Access Point), 20 bytes) of BSCP.
BSCP then fetches more accurate information about the
user, whereby the location of the customer service palette
is also found. If the user information is not found in the
BSMP in case, the user must give the address of his/her
Home BSCP (HBSCP). This enables usage of broadband
services from mobile stations.
Directory browsing :
In case of a new user, requesting of a service is proceeded
via directory browsing. BSCP knows one or more BSPs.
BSCP sends a BINAP message to BSS, which contains a
hypermedia document with links to BSPs. (Figure 7-5)
The first level of the hypermedia document contains the
BSPs (located at BSCP) and next levels contain all the
information the BSP has to offer, which are fetched by
BSCP from the BSP in case. BSCP does not have to
know all the services every BSP has to offer, but knowing
the addresses of the BSPs is sufficient. By using the
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Lappeenranta University of Technology and Telecom Finland 80
identification information of the user, the BSCP may
filter the information given to the user.
The hypermedia documents residing in BSPs contain
structured information about the type of service. The
types are controlled file transfer, hypermedia database or
single- and multiparty calls.
BSCP-ROOT_id
Telecom Finland SonyHPYNokia BIN Services Inc.
Media DB
XmosaicVOD AOD
Jazz Rock
Elvis Michael Jackson
Action Comedy
Stallone Schwarznegger
Cobra TerminatorRocky 1Real services
F
igure 7-5. The structure of directory tree.
Service palette process :
When the user has chozen the 'real' service, an icon can
be created to the customer service palette either to BSMP
or BSS. When such a service palette exists containing
icons and an accurate description of the parameters of the
service, may the service be executed via icon browsing
and activation. This enables much simpler and faster
usage of broadband services, because of icons' graphical
presentation and short-way execution process.
7.7.2 Service activation phase
After activation of the icon or 'real' service BSS informs
BSCP of it, which sends BSP a BINAP message
containing sufficient information about the icon or 'real'
service. In BSP the BSL for the service is executed. In
BSCP the QoS-manager is initialized for this connection,
which has received the QoS-parameters from the BSS.
The QoS-parameters are also negotiated with BSP and if
the user has too little network capacity, the BSP might
reject the service usage. The QoS-parameters could be the
limit values with what BSS could possibly function.
7.7.3 Service usage phase
This phase is highly dependent of the type of service
requested. For example, controlled file transfer type of
service could have the functions of PLAY and STOP.
During the service execution phase the QoS-manager is
responsible for the quality parameters of the service. The
parties inform BSCP of the changes in service quality,
which then tries to restore the values.
7.7.4 Service after-usage phase
After the service has been used, the user should inform
BSCP of the connection closing. BSCP then starts the
controlled connection close phase. BSCP has stored the
necessary information about the service usage eg. actual
usage time and ability to perform with the requested QoS-
parameters. The actual time here means eg. in controlled
file transfer the time between PLAY and STOP functions
summed through the whole session. The charging
information is then added to the MIB (Management
Information Base) in the BSMP of the user.
7.8 BINAP
7.8.1 BINAP-messages
BIN uses BINAP application protocol to communicate
with the external parties of BSCP. BINAP-messages have
been categorized into the following subclasses:
Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 81
INITIALIZATION:
User identification
Customer service palette
Directory handling
SERVICE USAGE:
Service type dependent control
messages during the service
usage
QoS-messages
SERVICE CLOSE:
Controlled closing messages
Customer charging
7.8.2 User identification
An example of an ASN.1 coded BINAP-message is given
here of the user identification, which BSS sends to BSCP
as the first message:
ServiceSubscribe ::= PRIVATE 1
SEQUENCE {
serviceUser
USERTYPE
}
USERTYPE ::= SEQUENCE {
name 0 NAME,
hbscp 1
HBSCPLOCATION,
account 2
ACCOUNTNUMBER
OPTIONAL
}
NAME ::= SEQUENCE {
forname 0 OCTET
STRING( SIZE(30)),
surname 1 OCTET
STRING( SIZE(30))
}
.
.
.
7.9 CUSTOMER SERVICE PALETTE
7.9.1 BIN conceptual model
The BIN conceptual model does not correspond with the
conventional IN conceptual model and it is divided into
to three planes: user, network and service planes. (Figure
7-6) The user plane contains the information about the
Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 82
user. The network plane defines all the possible networks
that the user system can interface with. The service plane
indicates all the possible services that the user can make
use of. The BIN conceptual model shows the correllations
of the three planes. The correlation between user and
network planes is such that the user has allowed networks
which can be accessed. The user and service plane
correllation defines the services that the user have
subscribed or installed. The network and service plane
correllation defines the services that can be provided in
the networks that the user is allowed to access.
USER PLANE
NETWORK PLANE
SERVICE PLANE
USER
ATM PLMNPOTSISDN
VOD UPTVideotel. AOD CC
Figure 7-6. BIN conceptual model.
7.10 BIN MIB
BIN MIB is the customer personal service palette and it
should be structured according to BIN conceptual model.
(Figure 7-7) The location of such a database can be either
in BSS itself or in HBSCP's BSMP.
This section just provides with a visio of the Broadband
IN Management Information Base (MIB) structure. The
idea is such that the customer will be provided with the
capability of remotely to configure his own service
palette that in telecommunications management language
is better known as a MIB. This MIB would contain all his
BIN service parameters and they could be configured
with the use of TMN at any time. Such parameters, in for
instance the videoconferencing service, would be the
names of the members of the conferencing group and
their corresponding network addresses in the lower layer
of MIB tree hierarchy. So, the customer BIN service
parameters could be described in the structure of a MIB
tree.
Customer ID
VOD
James Bond
Videoconferencing
Mike 546546
Jack 8797896
Sue 12325432Cliffhanger
Cape Fear
HDTVH.261
Figure 7-7. Visio of BIN MIB.
Actually the icons form the basis of this BIN MIB
framework. They contain all the information of the
service that has to be known by BSCP in order to be able
to execute the service. They include for example in VOD,
the BSP and its address, used picture formats and used
network. On the other hand, the allowed networks are
also listed with necessary parameters eg. transmission
speed. (Figure 7-8)
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Lappeenranta University of Technology and Telecom Finland 83
BIN MIB is designed to be managed with TMN
(Telecommunications Management Network) architecture.USER
VODAOD
MPEG 2 Mbit/sADPCM
ICONS NETWORKS
ATM PSTN ISDN IPHomeshop
USERPLANE
SERVICE PLANE NETWORK PLANE
64 kbit/s9.6 kbit/s8 Mbit/s
GSM
9.6 kbit/sH.261Anttila
ICONS
Stockmann
ATM
ATMISDN
IP
BSP-x
NSAP Address
BSP-x
ISDN Address NSAP Address
BSP-x
BSP-x
IP Address
Figure 7-8. A framework of BIN MIB.
7.11 TMN and BIN
In the previous sections were discussed about the
Broadband IN services. The services were static services
which could not be configured by the customer. The
meaning of this stage was just to have a view of BIN and
its possibilities. The next step is to have a remotely
configurable service database where the customer could
configure, for instance his VOD service table, remotely
and get the true VOD service capabilities. The aim of this
stage is to have a TMN configurable BIN service
parameters. The customer’s configure would affect the
BSCP database (MIB) and naturally also the BSMS,
because of the charging. (Figure 7-9)
B-IN MIB
Customer ATMswitch
Serviceproviders
VODHome shopping
TMN
Figure 7-9. The use of TMN in BIN.
7.12 The hardware configuration
The hardware configuration will consist of three Intel
386/486 (Linux) workstations (at first only one; without
the ATM network). Two of the workstations have a
videocamera with a videograbber and a Gravis
UltraSound (GUS) audiograbber. In the near future these
workstation will also have an adapter to ATM network
(i.e. an ATM card). A special videosoftware will be
driven in the two workstations, for instance IVS (INRIA
Videoconferencing System). The third workstation will be
kept as a Broadband Intelligent Network component B-
SCP, where the control software in driven. (Figure 7-10)
One of the workstations would contain the ATM network
simulator, which would forward cells with the aid of
VCIs. The network simulator would be static eg. use
PVCs and no signalling configurations could be 'on the
flight'.
Vide
ogr
abb
er
ATM switch
B-SSP
ATM
Linux workstation
B-SCP
ATM
ada p
ter
Grav
is Ult
raso
und
Linux workstation
Camera
Micro
pho
ne
Vid
eogr
abbe
r
ATM
ada p
ter
Grav
is Ult
raso
und
Linux workstation
Camera
Micr
o pho
neClient
Server
DB
Q.2391
- Video On Demand .
Figure 7-10. The BIN hardware configuration.
7.13 Proposed services
The aim of this project is to provide (server part) an
ordinary customer (client part) with BIN services. The
services in table 7.1 will at least be able to be provided.
The easisest one is the ordinary telephony service, and the
Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 84
difficultest is the videoconferencing which would need
multicasting capabilities from the Linux kernel and some
changes in the IVS videosoftware. The user interface
would such be implemented with the aid of 'old' software.
The BINAP messages would be implemented with CASN
ASN.1 compiler and the programming itself with the
CVOPS (C-language based Virtual OPerating System)
and later with the object-oriented telecommunications
software tool OVOPS (Object Virtual Operations
System). Here are some designed implementation
methods of certain services.
Videotelepho
ny
The IVS software is used to
encode and decode the audio and
video stream according to the
H.261 standard. The Graphical
User Interface is used to show the
moving images on to the screen.
VOD It would be using the IVS
videosoftware where the client
would request the B-SCP with a
service (a video) and the server
would then send it along the
ATM network to the client either
encoded with H.261 or MPEG
(Moving Pictures Experts
Group).
Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 85
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Tutorial on Intelligent Networks
Lappeenranta University of Technology and Telecom Finland 87
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