1. ECS5365 Lecture 4 Overview of B-ISDN
Philip Branch
Centre for Telecommunications and Information Engineering (CTIE)
Monash University

2. 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

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

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

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

6. 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

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

8. 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

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

10. B-ISDN Services Distributive Interactive Broadcast Multicast Messaging
Conversational
Retrieval

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

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

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

14. 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

15. 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

16. 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

17. 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

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

19. 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

20. 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

21. ATM Networks
ATM Switches
ATM to the desktop
Physical media

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

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

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

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

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

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

28. PDH
E1 - 2 Mbps
E2 - 8 Mbps
E Mbps
E Mbps

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

30. Synchronous Digital Hierarchy
STM Mbps
STM Mbps
STM Gbit/s

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

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

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

34. 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

35. 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)

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

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

38. Reading for next week
Stallings Chapter 15 “ATM Protocols”

39. 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?