IP Multimedia Subsystem-RKaczmarek

8/6/2019 IP Multimedia Subsystem-RKaczmarek

1/25

LEF BRIEFING SERIES

CSC GRANTS

IP Multimedia Subsystem (IMS):The Long and Winding Road

Richard Kaczmarek

September 11, 2008

1 2008 CSC


2/25

Outline

The business case for IMS

3GPP network architecture

IMS architecture

IMS variations

IMS de lo ments

LEF Briefing Series CSC Grants 2


3/25

What is IMS?

Developed by the Third Generation Partnership Project(3GPP), an international Standards Development Organization(SDO) associated with the Global System for MobileCommunications (GSM) service provider community

Developed on the principles of:

Consistent look and feel to user independent of location ayere arc ec ure app ca on p ane, con ro p ane an ranspor

plane)

Functional decomposition of each layer into entities

Standardized interfaces between entities (both horizontal and

vert ca



4/25

The Business Case for IMS

Investment (ROI) byProviding enhanced services to increase revenue and

customer lo alt

Providing a faster time to market due to a layered softwarearchitecture and standardized interfaces

Reducing capital expenditures (capex) after IMS

Reducing operational expenditures (opex) after IMSimplementation due to simplified operations on a singleinfrastructure



5/25

The Business Case for IMS

Potential Impediments to IMS

Cost of IMS deployments

Lack of a killer application

IMS variations



6/25

3GPP Network Architecture



7/25

IMS Architecture

AS

Application ServiceLayer

Le end

Basic Service Functionality

Interdomain Functionality

Miscellaneous Functionality

egen

I-CSCF S-CSCF

SLF

HSS

w

Mw

Dx Dx

Cx

Control Layer Signaling and Control

Interface

Bearer Interface

P-CSCF

MGCFMRFC BGCF

Mw

MgM

r

MjIBCF

MxMx

Mx

MxE-CSCF

LRF

Mw

MI

Mn

MGW

SGW

MRFP

Mn

MbTransportLayer TrGWPCRF

PCEF

IP NetworkIP NetworkANIP Network

SEG

IP Network PSTN

SEG


CSCF BGCF User Equipmentand Other IMS

NetworksUE


8/25

IMS Architecture Basic Components

AS


Le end




Legend

Application Server

Serving Call SessionControl Function

I-CSCF S-CSCF

SLF

HSS

w

Mw

Dx Dx

Cx


Interface

Bearer Interface

Provides enhancedservices to user

available to user

Controls resources in itsdomain

P-CSCF

MGCFMRFC BGCF

Mw

MgM

r

MjIBCF

MxMx

Mx

MxE-CSCF

LRF

Mw

MI

Mn Contains service and user

information

MGW

SGW

MRFP

Mn


PCEF

Proxy Call SessionControl Function


SEG

IP Network PSTN

SEG UE access into IMS Routes signaling to usershome S-CSCF



NetworksUE


9/25

Legend

IMS Architecture Interdomain Components

AS


Signaling and Legend




Multimedia ResourceFunction Processor

I-CSCF S-CSCF

SLF

HSS

MwMw

Mw

Dx Dx

Cx

Control Layer Signaling and ControlInterface

Bearer Interface

MnMn

Mixes incoming media

streams Transcoding,

announcements Managing access rights

P-CSCF

MGCFMRFC BGCF

MgM

r

Mj

IBCF

MxMx

Mx

MxE-CSCF

LRF

Mw

MI

Media Gateway Packet conversion

to circuit for bearer

packets

to shared conferencingresources

MGW

SGW

MRFP

Mn


PCEF

Transition Gateway IPv4 to IPv6 packet

conversion for


SEG

IP Network PSTN

SEGSecurity Gateway Enforces security policy

with other domains

bearer packets


CSCF BGCF User Equipmentand Other IMSNetworks

UE

Signaling Gateway SIP signaling to

SS7 signaling


10/25

IMS Architecture Interdomain Components

AS


Le end




Legend

Interrogating CSCF Used by P-CSCFs to

determine users S-CSCF

Subscription LocatorFunction Used by I-CSCF to

determine HSS associated

I-CSCF S-CSCF

SLF

HSS

w

Mw

Dx Dx

Cx


Interface

Bearer Interface

Access point for session

requests from otherdomains P-CSCFs

Interconnection BorderControl Function Interworking between SIP

P-CSCF

MGCFMRFC BGCF

Mw

MgM

r

MjIBCF

MxMx

Mx

MxE-CSCF

LRF

Mw

MI

Mn and other protocols (e.g.,H.323)

Can be used in place of I-CSCF

Multimedia ResourceFunction Controller Controls the MRFP

MGW

SGW

MRFP

Mn


PCEF

Breakout GatewayControl Function Determines network on

which PSTN

Media Gateway ControlFunction


SEG

IP Network PSTN

SEG

interworking is to occur on ro s n eropera on o

bearer channels betweenthe PSTN and the IMScore network



NetworksUE


11/25

IMS Architecture Miscellaneous Components

AS


Le end




Legend

I-CSCF S-CSCF

SLF

HSS

w

Mw

Dx Dx

Cx


Interface

Bearer InterfaceEmergency (911) CSCF Routes call to emergency

provider as opposed tousers home network Policy and Charging

P-CSCF

MGCFMRFC BGCF

Mw

MgM

r

MjIBCF

MxMx

Mx

MxE-CSCF

LRF

Mw

MI

Mn Rules Function Selects applicable

rules for session

MGW

SGW

MRFP

Mn


PCEF


SEG

IP Network PSTN

SEG

Function Identifies location of user

Policy and ChargingEnforcement Function Enforces applicable

rules for session



NetworksUE


12/25

IMS Variations

development Some 3GPP assumptions do not carry over to other SDO



13/25

IMS Variations

ance or e ecommun ca ons n us ry o u ons



14/25

IMS Variations

ance or e ecommun ca ons n us ry o u ons

Grouping of IMSentities into higherlevel components

Use of Service Broker toallow inter-a licationserver communications

More security functions,since networks do nothave same level of


networks


15/25

IMS Variations

European Telecommunications Standards Institute (ETSI)



16/25

IMS Variations

European Telecommunications Standards Institute (ETSI)

Added a PSTN/ISDNEmulation Subsystemto the signaling layer

Added Resource andAdmission ControlSubs stem to

Added Network AttachmentSubsystem to transport layer


transport layer


17/25

IMS Variations

vances o u me a u sys em -



18/25

IMS Variations

vances o u me a u sys em -

Service Broker manages

Both SIP and non-SIPbased applications

feature invocations andinteractions across

sessions

Application Manager SIPentity handling CSCF andPSTN routing

Services Data Manager HSS and AAA

Bearer Manager policyenforcement for QoS,security

functionality

Policy Manager unified

Security Manager detects anomalies



19/25

IMS Variations

Common IMS

by all SDOs Defined as the Core IMS plus selected additional IMS-



20/25

IMS Variations

Common IMS



21/25

CSCs Role in IMS Standards Development

CSC supports the National Communications System (NCS)in defining National Security / Emergency Preparedness(NS/EP) requirements and functions for the IMSarc ec ure an n a vanc ng ese requ remen s an

functions in the following standards organizations:Alliance for Telecommunications Industry Solutions (ATIS)

n erne ng neer ng as orce

Third Generation Partnership Project (3GPP)

MultiServices Forum (MSF)

CSC runs an eXperimental Testbed Environment (XTE) forthe NCS, which determines the feasibility / practicality ofvarious approaches to supporting NS/EP requirements

CSC uses Radvisions SIP Server Development Platform toprototype and demonstrate NS/EP functionality to industry



22/25

IMS Deployments

IMS vendors

Some failures / consolidation has

Telecommunications Equipment Manufacturers

Softswitch, IM/Presence,

Media Server, SBCEnd-to-end IMS Solution PDF, HSS, AS, NASS,

MRFC/MRFP, CSCF

CSCF, MGCF, BGCF,

MGW, SGWEnd-to-end IMS Solution

occurre

IMS product interoperability testing

End-to-end IMS Solution



AS, CSCF, HSS, MGCF,

PDF


Information Technology Suppliers

Multiservices Forum (MSF) GlobalMSF Interoperability (GMI)exercises

The XTE will be a host site in

WebLogic SIP Server(Service Broker)

OpenCall (Media Server,

AS and Service Broker,HLR, HSS, Signaling

Gateway, Location Server)

Tivoli Netcool IMS Manager,

WebSphere IMS Connector (AS)

Networking, Communicationsand Applications Servers

Networking, Communications

and Application Processors

SDP Tools

October 2008

IMS Forum Plugfest

GSM Association SIP Trials

SBC

AS, Media ServerAS Media Gateway,Multiservices Platform (AS)

IMS Test Suite Softswitch and AS AS AS, Media Server

CSCF, SBCLocation Server, Security

Server, OpenWeb (AS)

Resource Controller (QoS) Media Server


AS, CSCF, SMSIMS Test Suite

CSCF

eo a orm an a eway,IMS Software Development

Tools, IMS Test Suite

AS


23/25

IMS Deployments

Carrier Field Trials

Underway, but results are carrier-proprietary

-

First full IMS solutions anticipated to occur from 2009 2011. Reasonscited:

Need for the IMS s ecifications to be finalized and stable

Availability of complete IMS systems at reasonable price points

Availability of IMS revenue-generating data services

Ability to provide IMS-like services through more cost-effective non-IMScomponen s

Justifying IMS capex when existing networks have not yet been sufficientlyamortized

Determining how to operate hybrid IMS/non-IMS networks for maximum ROI

Identifying killer applications An additional 10+ years will be needed to fully convert to IMS-only

networks



24/25


25/25

Summary

IMS is an evolving set of standards that defines anenhanced services architecture for telecommunications

ere are erent var at ons o

IMS Products existField trials are occurring

Hybrid IMS / non-IMS networks exist

Migration to IMS-only networks depends on the businesscase / ROI for IMS and may take years

Development Platforms

Will work in existing hybrid networks and future IMS networks

Have an IMS issue? Contact CSC


IP Multimedia Subsystem-RKaczmarek

Documents