ECS5365 Lecture 4 Overview of B-ISDN Philip Branch Centre for Telecommunications and Information Engineering (CTIE) Monash University http://www.anspag.monash.edu.au/~pbranch/masters.ppt

References Stallings, W., “ISDN and Broadband ISDN with Frame Relay and ATM”, 3rd Edition, Prentice-Hall, 1995 dePrycker, M., “Asynchronous Transfer Mode: Solution for Broadband ISDN”, 3rd Edition, Prentice-Hall, 1995 Partridge, C., “Gigabit Networking”, Addison-Wesley, 1994

Outline Need for Broadband ISDN B-ISDN applications B-ISDN solution B-ISDN layers Physical layer B-ISDN/ ATM Standards Bodies

What is Broadband-ISDN? A Full Services Network (FSN) Multiple services / one network Integrates video, voice, data Telco term more than Private network term

Need for B-ISDN Limitations of N-ISDN Statistical multiplexing Scalable bandwidth New applications Video Applications LAN-LAN connectivity networks Quality of service

Quality of service Different requirements for data, voice and video low delay and delay variation tolerant of loss Data tolerant of delay and delay variation intolerant of loss

Scalable bandwidth New applications bursty Need bandwidth available on demand Very fine units of bandwidth

Statistical multiplexing Based on the Central Limit Theorem Multiplex n independent and identically distributed random time varying signals Mean of aggregate increases proportionally to n Standard deviation of aggregate increases proportionally to sqrt(n) variation of aggregate signal decreases proportionally as n increases

B-ISDN Driver Technologies Optic Fibre (Photonics) High performance PCs Digital Signal Processing Chips Sophisticated software

B-ISDN Services Distributive Interactive Broadcast Multicast Messaging Conversational Retrieval

Examples of Distributive Services Broadcast Broadcast Television Multicast Near video-on-demand

Examples of Interactive Services Messaging video mail Retrieval video-on-demand Conversational video-conferencing

BISDN Design Decisions Cell Switching No feedback control later changed Sophisticated Quality of Service guarantees

Cell Switching Connection oriented packet switching Small uniform size packets 48 byte payload, 5 byte header compromise between 64 and 32 bytes Advantage of cells simple switch architectures scalable bandwidth

Connection Oriented Connection established end to end before transmission of data ‘Virtual Circuit’ and Virtual Circuit Indicator Lower delays during transmission Connections can be blocked Control over quality of service

Packet Switching Information segmented for transmission and reassembled at destination Information in packets Each packet has a tag indicating destination Packets from multiple calls statistically multiplexed Can be delays caused by switch buffering

Asynchronous Transfer Mode Fast packet switching technology Cell relay Small, fixed size packets (cells) Segmentation and Reassembly Connection Oriented Virtual Circuit Indicator Application Adaptation Layer protocols

No feedback control Bandwidth time product Congestion events transient large number of bits in transit Congestion events transient Feedback control useless

Quality of Service Defined in terms of Need to know Cell loss rate Delay Delay variation Need to know Bit rates Burstiness QoS used in connection admission control

ATM’s Mixed Success Quality of service a great success Statistical multiplexing less successful Data sources are not identically, independently distributed Video has a periodic, rather than a random time varying nature Data packets over cells easily causes congestion collapse single cell loss causes whole packet to be discarded Feedback control introduced in ABR

ATM Networks ATM Switches ATM to the desktop Physical media

Broadband ISDN Protocol Reference Model Higher Layers ATM Adaptation Layer ATM Layer Physical Layer

Higher Layers Application layer Examples Packets for IP network Frames for HDLC network Voice stream for telephony MPEG transport stream for video

ATM Adaptation Layer Maps higher layer to ATM cells AAL for different applications Segments and reassembles cells for ATM Much more next lecture

ATM Layer Cell relay switching technology 53 Octets (bytes) cells 5 byte header 48 byte payload Much more in later lectures

Physical Layer ATM Transmission Media Originally only 2 - 155 and 622 Mbps analogous to Basic and Primary Rate Interface New sublayers at different transmission rates

Transmission Rates Plesiochronous Digital Hierarchy (PDH) SynchronousOptical NETwork (SONET) Synchronous Digital Hierarchy (SDH) ATM to the desktop

PDH E1 - 2 Mbps E2 - 8 Mbps E3 - 34 Mbps E4 - 140 Mbps

Synchronous Optical Network (SONET) STS-3 (OC-3) - 155 Mbps STS-12 (OC-12) 622 Mbps STS-48 (OC-48) 2.4 Gbit/s

Synchronous Digital Hierarchy STM-1 155 Mbps STM-4 622 Mbps STM-16 2.4 Gbit/s

Desktop ATM TAXI - 100 Mbps OC3 - 155 Mbps FDDI based. Superseded OC3 - 155 Mbps Multimode fibre connection STS-3 over UTP Category 5 - 155 Mbps UTP Category 5 25 Mbps UTP Based on Token Ring interface

B-ISDN Standards Bodies ITU - International Telecommunications Union ATM Forum IETF - Internet Engineering Taskforce

ITU Groups SG9 - Television and sound transmission SG11 - signalling and switching SG13 - general network aspects SG15 - transmission systems and equipment

ITU Recommendations I.413 B-ISDN User Network Interface I.432 B-ISDN UNI Physical Layers I.361 B-ISDN ATM Layer Specification I.363 B-ISDN ATM AAL Specification I.371 Traffic and Congestion Control in B-ISDN

ATM Forum Specifications LAN Emulation (LANE) Traffic management v4.0 Private Network to Network Interface (PNNI) v.1 Physical Layers User to Network Interface (UNI) v 3.1 UNI Signalling v 4.0 Multi-Protocol Over ATM (MPOA)

IETF RFCs RFC1483 “Multiprotocol Encapsulation over ATM Adaptation Layer 5” RFC1577 “Classical IP and ARP over ATM”

Summary Need for Broadband ISDN B-ISDN applications B-ISDN solution B-ISDN layers Physical layer B-ISDN/ ATM Standards Bodies

Reading for next week Stallings Chapter 15 “ATM Protocols”

Review Questions Why is connection admission control in B-ISDN more difficult than in N-ISDN? Is ATM a layer 2 (data link) or layer 3 (network) protocol? Why not overcome the time propagation delay problem by installing switches with large buffers? Suppose we have a video sequence whose mean bandwidth is 1 Mbps and standard deviation is 0.5 Mbps. Assuming independence between the streams, what will be the mean and standard deviation of an aggregate stream consisting of 10 such sequences? 100? 1000?