CS575 ATM Technology: Introduction 1

104/22/23 05:14

Rivier College

CS575: Advanced LANs

ATM Technology: Introduction

CS575 ATM Technology: Introduction 2

204/22/23 05:14

Table of Contents

Section 1 IntroductionSection 2 ATM Layers and Protocol

2.1 Physical Layer2.2 ATM Layer2.3 ATM Adaptation Layer

Section 3 Traffic ManagementSection 4 Signaling and AddressingSection 5 Private-Network-to-Network Interface (PNNI)Section 6 ATM LAN EmulationSection 7 IP Over ATM Section 8 Multiprotocol Over ATM (MPOA)

Tableof

Contents

CS575 ATM Technology: Introduction 3

304/22/23 05:14

Section 1: ATM Technology Overview

0 Background 0 B-ISDN Services0 What is ATM?0 Why ATM?0 How Does ATM work?0 ATM Networks0 ATM Interfaces0 ATM and Legacy Networks0 ATM Switches and Edge Devices0 B-ISDN/ATM Protocol Reference Model0 ATM Standards Organizations

CS575 ATM Technology: Introduction 4

404/22/23 05:14

Background0 1984: ITU-T (CCITT) developed standards for ISDN0 Types of ISDN (Integrated Services Digital Network) channels

CS575 ATM Technology: Introduction 5

504/22/23 05:14

Background (continued)

0 Two types of interfaces were specified:- Basic Rate Interface (BRI): 2B+D 144 Kbps (192 Kbps

Interface structure gross bit rate)- Primary Rate Interface (PRI): 23B+D/30B+D 1.536/1.984 Mbps

(1.544/2.048 Mbps gross bit rate)

CS575 ATM Technology: Introduction 6

604/22/23 05:14

Background (continued)

CS575 ATM Technology: Introduction 7

704/22/23 05:14

Background (concluded)

0 1985: ITU-T Study Group 13 (formerly the CCITT Study Group XVIII) began developing standards for Broadband ISDN (B-ISDN)

0 Objective: Define a B-ISDN transport technology for all types of traffic (voice, video, image, and data) for broadband services

0 1988: ITU-T selected Asynchronous Transfer Mode (ATM) as the switching and multiplexing technique for the B-ISDN

0 ATM was developed for B-ISDN, but it is also implemented in non-ISDN environments where very high data rates are required

CS575 ATM Technology: Introduction 8

804/22/23 05:14

B-ISDN Services

B-ISDN Services

InteractiveServices

DistributionServices

DistributionServiceswith userControl

DistributionServices

without userControl

MessagingServices

ConversationalServices

RetrievalServices

CS575 ATM Technology: Introduction 9

904/22/23 05:14

What is Asynchronous Transfer Mode (ATM)?0 Asynchronous Transfer Mode (ATM) is a connection-oriented, high-speed,

low-delay switching and transmission technology that uses short and fixed-size packets, called cells, to transport information.

0 Using the cell switching technique, ATM combines the benefits of both circuit switching (low and constant delay, guaranteed capacity) and packet switching (flexibility, efficiency for bursty traffic) to support the transmission of multimedia traffic such as voice, video, image, and data over the same network.

5 octets 48 octets

53 octets

Header Information

CS575 ATM Technology: Introduction 10

1004/22/23 05:14

Why ATM?

0 International standard-based technology (for interoperability)0 Low network latency (for voice, video, and real-time applications)0 Low variance of delay (for voice and video transmission)0 Guaranteed quality of service0 High capacity switching (multi-giga bits per second)0 Bandwidth flexibility (dynamically assigned to users)0 Scalability (capacity may be increased on demand)0 Medium not shared for ATM LAN (no degradation in performance as

traffic load or number of users increases)0 Supports a wide range of user access speeds 0 Appropriate (seamless integration) for LANs, MANs, and WANs 0 Supports audio, video, imagery, and data traffic (for integrated services)

CS575 ATM Technology: Introduction 11

1104/22/23 05:14

ATM Network

How Does ATM Work?

H

H

H H H

H

H

H

Voice Video Data Voice Video Data

BISDNServices

BISDNServices

Reassembly

User Applications User Applications

Workstation Workstation

Multiplexing Demultiplexing

H H H HH H

Segmentation

CS575 ATM Technology: Introduction 12

1204/22/23 05:14

How Does ATM Work? (concluded)

0 ATM is connection-oriented -- an end-to-end connection must be established and routing tables setup prior to cell transmission

0 Once a connection is established, the ATM network will provide end-to-end Quality of Service (QoS) to the end users

0 All traffic, whether voice, video, image, or data is divided into 53-octet cells and routed in sequence across the ATM network

0 Routing information is carried in the header of each cell0 Routing decisions and switching are performed by hardware in

ATM switches0 Cells are reassembled into voice, video, image, or data at the

destination

CS575 ATM Technology: Introduction 13

1304/22/23 05:14

ATM Networks

0 Public ATM Network:- Provided by public telecommunications carriers (e.g., AT&T,

MCI WorldCom, and Sprint)- Interconnects private ATM networks- Interconnects remote non-ATM LANs- Interconnects individual users

0 Private ATM Network:- Owned by private organizations - Interconnects low speed/shared medium LANs (e.g., Ethernet,

Token Ring, FDDI) as a backbone network- Interconnects individual users as the front-end LAN for high

performance or multimedia applications

CS575 ATM Technology: Introduction 14

1404/22/23 05:14

ATM InterfacesPrivate

UNI

Private ATM LAN

PublicUNI

Public ATM Network

Public ATM Network

B-ICI

Private ATM WAN

P-NNI

CS575 ATM Technology: Introduction 15

1504/22/23 05:14

Public ATM Network

ATM and Legacy Networks

TokenRing

TokenRing

FDDI

FDDI

MainframeComputer

Video

Video

Video

Ethernet

Ethernet

MainframeComputer

Edge Switch

Ethernet

FileServer

PrivateATM

Switch

Edge Switch

Edge Switch

Edge Switch

PBX

PBX

Voice

Voice

Private ATM

Network

FDDI

CS575 ATM Technology: Introduction 16

1604/22/23 05:14

ATM Switches and Edge Devices

0 ATM Switches- ATM LAN switches- ATM Backbone switches- ATM WAN switches- ATM Central Office switches

0 ATM Edge Devices- ATM capable routers- ATM capable switches

CS575 ATM Technology: Introduction 17

1704/22/23 05:14

Examples of ATM Workgroup Switches

Marconi LE-155ATM Workgroup Switch

Cisco Systems LS-1010ATM Workgroup Switch

CS575 ATM Technology: Introduction 18

1804/22/23 05:14

Examples of ATM Backbone Switches

Marconi ASX-1000ATM Backbone Switch

Marconi ASX-200ATM Backbone Switch

Marconi ASX-4000ATM Backbone Switch

CS575 ATM Technology: Introduction 19

1904/22/23 05:14

Examples of ATM WAN Switches

Lucent GX 550ATM Switch

Cisco SystemsCatalyst 8500 Multiservice

Switch Router

CS575 ATM Technology: Introduction 20

2004/22/23 05:14

Examples of ATM Edge Devices

Marconi ES-381010/100 Ethernet Switch

Cisco SystemsCatalyst 5500 Switch

Marconi ESX-3000Campus Switch

CS575 ATM Technology: Introduction 21

2104/22/23 05:14

B-ISDN/ATM Protocol Reference Model

Source: Stallings: Data and Computer Communications

CS575 ATM Technology: Introduction 22

2204/22/23 05:14

Appendix: B-ISDN Services

0 Retrieval Services- Video retrieval service

=Entertainment =Remote education and training

- High-resolution image retrieval service=Entertainment =Remote education and training=Professional image communications=Medical image communications

- Document retrieval service=Mixed documents containing text, graphics, still and moving picture

information, and voice annotations from archives or information centers

CS575 ATM Technology: Introduction 23

2304/22/23 05:14

B-ISDN Services (continued)

0 Messaging services- Video mail service for the transfer of moving pictures and

accompanying sound- Document mail service for mixed documents containing text, graphics,

still and moving picture information, as well as voice annotations 0 Conversational services

- Broadband videotelephony for the transfer of voice (sound), moving pictures, and video scanned still images and documents between two locations for

=Tele-education=Tele-shopping=Tele-advertising

- Broadband videoconference

CS575 ATM Technology: Introduction 24

2404/22/23 05:14

B-ISDN Services (concluded)

0 Distribution services without user control- Document distribution

=Electronic newspaper=Electronic publishing

- Video distribution service=TV program distribution=HDTV program distribution=Pay-per-view TV program distribution

0 Distribution services with user control- Video broadcast for

=Remote education and training=News retrieval=Video-on-demand

CS575 ATM Technology: Introduction 25

2504/22/23 05:14

B-ISDN/ATM Standardization0 ITU-T

- ITU-T is the Telecommunications Standardization Sector of the International Telecommunication Union (ITU)

- It is the new name for CCITT- It is in charge of setting network standards for public

telecommunications- The ITU-T functions are carried out through study groups- Study Group 13 is responsible for setting standards (“I”, “Q”, and “F”

Series Recommendations) for B-ISDN 0 ATM Forum (ATMF)

- An international non-profit organization formed in September 1991- Since then, it has expanded to include more than 750 voting members

from ATM equipment vendors, service providers, carriers, and users

CS575 ATM Technology: Introduction 26

2604/22/23 05:14

B-ISDN/ATM Standardization (concluded)

- Objective: To accelerate the use of ATM products and services through interoperability specifications

- The ATM Forum has a technical committee which works with other standards bodies such as ITU-T and ANSI to recommend new standards as well as to resolve any standards issues

- The Technical Committee consists of a number of working groups to investigate different areas of ATM technologies

- Working groups are responsible for producing technical specifications

CS575 ATM Technology: Introduction 27

2704/22/23 05:14

W. Stalling, Local and Metropolitan Area Networks, 6th edition, Prentice Hall, 2000, Chapter 11

References

W. Stalling, Data and Computer Communications, 6th edition, Prentice Hall, 2002, Chapters 11-12

A. Wu, Advanced Local Area Networks, Lectures & Slides, Rivier College, 2001.