Advanced Seminar on ATM April 16, 1996 - Liège
		O. Bonaventure A. Danthine

Introduction

This advanced ATM seminar is intended for people having already an in-depth knowledge of ATM. During the first part, we will discuss the problems linked to the traffic management in ATM networks, and during the second part the evolution of the LAN Emulation as well as the VLAN concept.

The attendees are assumed to have a working knowledge of ATM which is at least equivalent to the material covered during the two-days CSS seminar on ATM.

The Traffic Management is an important function for tomorrow's ATM networks. It covers both Traffic Control and Congestion Control. During this seminar, we will first discuss the support of Constant Bit Rate and Variable Bit Rate traffics within ATM networks. Then, we will concentrate on the new services that have been defined to better support data applications. Our presentation will mainly focus on congestion control issues. We will also present the fast reservation protocols, which are being considered within ITU.

Table of Contents

1. The CBR and VBR service classes
   • The four service classes proposed by ITU
   • The CBR traffic contract
   • The CBR service class in ATM Forum UNI 3.1, UNI 4.0 and ITU
   • The VBR traffic contract
   • The VBR service class in ATM Forum UNI 3.1, UNI 4.0 and ITU

2. The UBR service class
   • Motivations
   • Characteristics of the UBR service class
   • Congestion control in data networks
   • Congestion control in TCP/IP networks
   • TCP over UBR ATM
   • Discarding strategies : PPD and EPD
   • Congestion control in DECNET and CLNP networks
   • Is EPD really the solution to all congestion problems ?
   • The UBR service class in ATM Forum UNI 3.1, UNI 4.0 and ITU

3. Congestion control in the ATM layer : towards the ABR service class
   • Motivations
   • Design goals for the ABR congestion control
   • The rate-based proposals
     • The "bit-rate-based" schemes
     • The "explicit-rate-based" schemes
   • The credit-based proposals
     • Flow control at the UNI with the GFC
     • The other credit-based proposals
   • The rate-based versus credit-based debate

4. The ABR service class
   • More on the rate-based proposal selected by the ATM Forum
     • Behaviour of the sources
     • Behaviour of the destinations
     • Behaviour of the switches
   • Virtual sources and virtual destinations
   • Congestion control for point-to-multipoints connections
   • Policing issues
   • The ABR service class in ATM Forum UNI 4.0 and ITU

5. Fast reservation protocols : an alternative to ABR ?
   • Motivations
   • Some early proposals
   • The fast reservation protocol proposed within ITU
   • The ABT service class of the ITU
   • The higher layer protocols and the fast reservation protocols

Olivier Bonaventure graduated from the University of Liege as in 1992. Since then, he has worked as a researcher in the research unit in networking and has been involved in the ESPRIT OSI95 project and the RACE CIO and ACCOPI projects. He is currently working on transport protocols in the ATM environment within the OKAPI ACTS project. He has published several papers in the field and has been a reviewer for several conferences.

The LAN Emulation concept is not very difficult to grasp but its implementation is far from obvious. The three servers, the LECS, the LES and the BUS are interacting with the LEC in a non-trivial manner and in a time consuming way which may interfere with the expected behaviour of the LANE user.

The first standard produced in January 1995 by the ATM Forum has been revised and a new draft has been issued in February 1996. In the tutorial, we will examine the new proposal and study a possible scenario of deployment. The place to implement the LAN Emulation servers is not without implication with the reliability and the management aspects.

When used as a backbone between legacy LANs implemented with switching hubs, the LANE is perceived, at first sight, as a very useful technology for implementing the new concept of Virtual LAN in a flexible manner.

This approach is however not as general as it may look at first sight. This LANE approach must therefore be compared with a more direct ATM-based approach in order to evaluate its long term interest.

André DANTHINE, Professor at the University of Liège since 1967, created a research unit in networking (RUN) in 1972. In 1983, Professor Danthine launched the ESPRIT I Project 73 aiming at the development of a high speed network for the interconnection of heterogeneous LANs on a broad site. This project ended up, in 1989, with the installation, on the Sart Tilman Campus of the University of Liège, of the BWN (Backbone Wideband Network) prototype (more than 18 km of optical fibre with a data rate of 140 Mbps).
In 1990, Prof. Danthine launched a new Esprit project, OSI95, to tackle the problem of the design of a new transport service and protocol (TPX) for multimedia applications in a high speed environment including B-ISDN. In 1991, he joined the RACE Project CIO. It is in the framework of this project that the ATM LAN of RUN has been connnected, at 34 Mbps, to the European ATM Pilot for functional and performance evaluations. Since 1994, Prof. Danthine is also involved in another RACE project, ACCOPI. November 1995 was the starting point of OKAPI, an ACTS project.
Since 1992, Prof. Danthine is the chairman of the COST action 237 on "Multimedia Telecommunication Services".
Prof. Danthine is a member of ACM, of IEEE, of the Editorial Board of "ETT", of the Editorial Advisory Board of the Wiley Series in "Communication and Distributed Systems", editor of several books and proceedings and author of more than eighty papers. Chairman of the TC6 of IFIP from 1979 to 1985, he is Governor of ICCC since 1982. CRB Fellow in 1960, he received the Melchior Salier Prize in 1961, the "Bell Telephone-100th Anniversary" prize in 1983 and the IFIP Silver Core in 1986. In 1993-1994, he was Francqui Professor at the VUB. He is Doctor of Science Honoris Causa of the University of Kent (1991).