Pricing Network Services

Network Services

Network Services

A classification of network services

Telecommunication Services - 3

Contents

Transport and value-added services

Layering

The Internet Value Chain

Business Models


What are networks

Data transport service between

applications

access

Telecommunications network (Logical) circuit services

Packet routing services

ΑΤΜ

Frame Relay

SDH

ISDN

Ethernet

Internet (IP)

Pipe for bits = optical fiber

satellite channel

wireless channel


Connection and connectionless services

Connection-oriented services have the semantics of a

directed virtual pipe (or perhaps a tree)

R bps, delay T, error rate r

Deliver message of size M to A,B with delay T and ber = r

AB

Connectionless services have the semantics of a

datagram service (perhaps to multiple destinations)


Multiplexing

1

2

Fixed TDM

(circuit-switching)

1

2

Statistical TDM

(packet-switching)


Layering in multiplexing

light path

SDH connection

ΑΤΜ VP

IP flow

Application creates flow between Α - Β. What technology will the network choose to support the flow?

Light path: 2.5 GbpsSDH: 155-2.5Gbps (PDH:34Mbps)ATM: 0-2.5GbpsIP: 0-...

pipes of constant size

Fills what it finds! (does not define pipe)


A hierarchy of transport services

guaranteed BW,

Fine - medium granularity

guaranteed BW

Protocol transparency

ATM,

FR

SONET,

SDH

shared+ guaranteed BW

Ethernet

Fiber with DWDM

shared BW

(no QOS)

TCP/IP, UDP/IP

x/IP: short – long lived bursty connections, edges control connection setup,

no BW guarantees, statistical multiplexing

ATM, FR: long lived connections, network controls connection setup, fixed BW

Ethernet: two modes: shared BW (for short lived bursty connections)+ guaranteed

BW (for long lived fixed rate connections)

Fiber using DWDM: long lived connections (for now), protocol transparency

medium – coarse granularity

Network Services

The Internet value chain


The Internet Value Chain

Infrastructure Services Layer: simple services that are bought from the other layers

Bit-pipe level connectivity, equipment, call-center services, billing

Internet Services Layer:

End-to-End Connectivity Services: IP connectivity services(unicast, multicast, streaming,…), connection with applications (data centers) and with users

– data center, IP backbone, access, end-user IP network, distribution

Content Providing Services: content services: applications, telecommunication services to the end-user, e-commerce

– Application Service Provider (ASP), Content Provider (CP), Electronic Marketplace Provider (EMP), Communication Service Provider, Internet Retailer

End-User Layer


The Internet Value Chain (cont.)

userApplications

and content

(ASP)

Server farm

Backbone

Access

ISP

Bit pipes


The Internet Value Chain (cont.)

Internet Service Layer

Financial

Service Provider

Connectivity Provider

Information Provider

End-User

Billing

Service Provider

Infrastructure Layer

Network Component

Service Provider

(Dark fiber, , SONET

Ethernet, Satellite,…)


Internet Retailer

Internet Service Provider

Information ProviderConnectivity Provider

End-User

Access Provider

Backbone Provider

Data Center Application Service Provider

Content Provider

Internet Retailer

Communication Service Provider

End-User Network Provider Market Place Provider

ISP Reference Business Model


End- user

Backbone

Provider

Generic

ISP

Internet

Retailer

Business Relationship

Backbone

Provider

Communication

Service provider

Access

Provider

Stakeholder

Business Model: typical ISP


Data Center Provider

End User Information Provider

Access and Backbone Provider

Money flow

Physical Line

Connection

Value Chain Example


Examples of ISP Business Models

XXCommunication

XXRetailer

XContent

XApplication

XXData Center

XBackbone

XXXXAccess

AkamaiExodusCovadMindspring/Ear

thlinkAOLService


AOL Mindspring

/EarthlinkCovad Exodus Akamai

Customer Residential

End-Users

Residential

End-Users

Business

Customers

Business

Customers

Business

End-Users

Addressed

Needs of

Customers

Backbone

Connectivity

and Content

Broadband

and

Narrowband

and Hosting

Broadband

Access and

VPN

Reliable

Information

Delivery

Fast Content

and Streaming

Media

Delivery

Owned

Services

Content Hosting Access and

Backbone

Backbone and

Data Centers

Data Centers

Bundled in

Services

Access and

Backbone

Access, Data

Center, and

Backbone

--- Broadband

Access

---

ISPs market segmentation


Backbone

Provider

Access

Provider

Internet

Retailer

Content

Provider

AOLInternet

Retailer

Content

ProviderCommunication

Service

Provider

End User

Stakeholder

Business Relationship

AOL Business Model

Network Services

Service contracts


Contents

Service contracts

Best-effort and guaranteed services

Policing


Service contracts

Services = packet/cell transport service (1->1, 1->M)

Traffic contract = connection’s (or flow’s) performance +

traffic profile user must conform to

Unicast: usually sender initiates service establishment

Multicast: might be receiver initiated, more flavours

Network

Service

Interface

Service contract


Guaranteed and best-effort services

Guaranteed services (contracts):

network provides some form of performance guarantees in terms of loss, delay, and delay jitter

users request some amount of resources

subject to admission control

Best-effort services (contracts):

no specific performance guarantees

performance deteriorates during overload periods

no specific bandwidth request

intended for applications that can adapt sending rate

– elastic applications


Guaranteed services

Performance guarantees

Quality of Service (QoS): loss, delay, and delay jitter

statistical (e.g., loss < 10-7) or deterministic (delay < 30 ms)

Required mechanisms:

Connection Admission Control (CAC)

Policing

User-network traffic contract: connection’s QoS and traffic description:

Network promises to support the specified QoS,

provided the user’s traffic is within his traffic contract


Best-effort services

No specific performance guarantees, but can provide some form of fair treatment to different connections

Feedback mechanisms inform source of congestion

Explicit (binary, rate), implicit (packet loss)

Mechanisms in routers/switches to share bandwidth, enforce fairness, etc.

Example of source behaviour

increase (additive) when there is no congestion

decrease (multiplicative) when there is congestion

Examples:

ABR: rate-based flow control (EFCI, Explicit Rate)

Internet: TCP flow control


Policing: leaky buckets

r = leak rate (cells/s) , b = bucket size (cells)

Real cell arriving

Virtual cell

b cells

r cells/s

Arriving cell = conforming : there is space in token bucket

= non-conforming : no space for complete cell

Case of variable size cells (packets): measure r in bytes/s


The Leaky Bucket

copier

1/s 100/s

.1

100 same connections

10

Properties:

• the central buffer never

overflows

• maximum delay = .1s

In time t the source can transfer

maximum volume of liquidt1.

t1.

Wide Area Networking


What is interconnection

Technologies: circuit switched, packet switched

Circuit switched: leased lines, ISDN (based on PSTN)

Packet switched: ATM, Frame Relay, IP VPNs

Dark fiber, light paths

LAN 1 LAN 2

Router A Router B

WAN service


Service contracts

The network service is described by a contract (Service Level Agreement, SLA)

The contract includes

the responsibilities of the network

– maximum delay, losses, jitter, …

the responsibilities of the client

– maximum rate, burstiness, ...

SLA


Multiplexing

1

2

Fixed TDM

(circuit-switching)

1

2

Statistical TDM

(packet-switching)


The economics of multiplexing

multiplexing is driven by economics

Different technologies suited for different customer traffic

needs


A simple model

Α

Β

C

D

Post offices Α, Β, C,...

K packets/sA B

Interconnection service

< K/3 p/s

K/3 p/s

Smart management of container space:

overbooking

Container for K packets

1 s

New interconnection

service

Container service


Multiplexing technologies

ATM

SONET

IP packets

IP router

Optical fiber

Light paths

622 Mbps35 Mbps

54Kbps


ATM και SDH

SDH

ATM

switch

ATM networkrouter

virtual path

ATM

switch


The hierarchy of multiplexing services

guaranteed BW,

Fine - medium granularity

guaranteed BW

Protocol transparency

ATM,

FR

SONET,

SDH

shared+ guaranteed BW

Ethernet

Fiber with DWDM

shared BW

(no QOS)

TCP/IP, UDP/IP

x/IP: short – long lived bursty connections, edges control connection setup,

no BW guarantees, statistical multiplexing

ATM, FR: long lived connections, network controls connection setup, fixed BW

Ethernet: two modes: shared BW (for short lived bursty connections)+ guaranteed

BW (for long lived fixed rate connections)

Fiber using DWDM: long lived connections (for now), protocol transparency

medium – coarse granularity


Circuit-switched WAN services

Dark fiber and light paths

Leased lines

ISDN TDM


Dark fiber and light paths

With dark fiber, the customer leases the fiber itself and buys the necessary

equipment to actually activate the fiber

The customer pays for the physical media, not for bandwidth

As the customer adds equipment that can either pulse more bits per

second or extract more wavelengths out of the underlying fiber, the

bandwidth essentially becomes cheaper and cheaper

Light paths: customer buys an optical network service: end-to-end transport

of light of a particular colour, with transparency w.r.t. to network technology


Leased lines

Point-to-point, multipoint, managed, fractional services, offered by PSTN

infrastructure, PDH (E1,E3,T1,T3, FE1,..), SDH (OC3..)

Single-purpose leased-line networks


ISDN

One of the ideas behind narrowband ISDN (N-ISDN) was to give customers

one access into the network, from which they could then engage in circuit-

switched, leased-line, or packet-switched options

Although all these options were available before ISDN, each one generally

required its own special access line and device, which meant extra costs

and administrative responsibilities because of the large number of options

The goal of ISDN was to provide one plug into the network, from which you

could then go out over multiple alternatives.


Packet-switched WAN services

Based on virtual-circuits (provide QoS)

ATM

Frame Relay

MPLS

Based on packet switching

Ethernet

IP (Internet) connectivity


Virtual Circuits

a

b

c

b

c

d

c

d

S1

S2

S3

d

a

a

b

e

1

1

1

1

1

a,1: d,1

a,1: e,1 and c,1

a,1: b,1

12

1

c,1: d,2

a,2: b,11

2

1

d,1: e,2

a,2: c,1

VC data

ATM cell

12

1


ATM: cell switching

25 25 25

34

30

ATM switchCell

Header

(VPI/VCI)

Payload

30 49

input

port 1

output

port1

output

port 2input

port 2

Input Port VPI/VCI Output Port VPI/VCI

1 25 2 341 30 1 49

Internal Routing Table


Multi Protocol Label Switching (MPLS)

IP is a connectionless protocol, it cannot guarantee that network resources

will be available

MPLS allows to define network connections (like VCs) with QoS for specific

IP packet flows which bypass intermediate routers

Provide differential treatment for the above IP flows

MPLS offers the advantages of circuit-switching technology—including

bandwidth reservation and minimized delay variations, which are very

important for voice and video

It enables service providers to create VPNs that have the flexibility of IP

and the QoS of ATM


MPLS architecture


Virtual networks

R1

R2

R3

R4

R1

R2

R3

R4

R1

R2

R3

R4

R1

R2

R3

R4

IP network

R

R R

R

Leased line network

ATM network

Logical network Using leased lines

Using ATM Using IP VPN

Pricing Network Services

Documents

medium granularity sonet

long lived connections

fixed bw ethernet

udp ip shared bw

guaranteed bw

statistical multiplexing atm

dwdm protocol transparency

shared bw