Multimedia Multicast Transport Service for Groupware.

Authors: Gregory V. Chockler, Nabil Huleihel, Idit Keidar and Danny Dolev.

In the TINA Conference on the Convergence of Telecommunications and Distributed Computing Technologies, September 1996, pages 43-54.


Reliability carries different meanings for different applications. For example, in a replicated database setting, reliability means that messages are never lost, and that messages arrive in the same order at all sites. In order to guarantee this reliability property, it is acceptable to sacrifice real-time message delivery: some messages may be greatly delayed, and at certain periods message transmission may even be blocked. While this is perfectly acceptable behavior for a reliable database application, this behavior is intolerable for a reliable video server. For a continuous MPEG video player, reliability means real-time message delivery, at a certain bandwidth; It is acceptable for some messages to be lost, as long as the available bandwidth complies with certain predetermined stochastic assumptions. Introducing database style reliability (i.e. message recovery and order constraints) may violate these assumptions, rendering the MPEG decoding algorithm incorrect.

A desktop and multi-media conferencing tool, is a Computer Supported Cooperative Work (CSCW) application incorporating various activities such as video transmission and management of replicated work space. These activities obviously require different qualities of service, and yet are part of the same application. Furthermore, CSCW applications often need to be fault-tolerant, and need to support smooth reconfiguration when parties join or leave. Groupware is a powerful tool for the construction of fault-tolerant applications, providing reliable multicast and membership services with strong semantics. In this paper, we incorporate multiple quality of service options within the framework of groupware systems. This way, a single application can exploit multiple quality service options, and can also benefit from the groupware semantics.

Postscript Version: ps, ps.gz. Israel mirror site: ps.gz.

The full version of this paper can be found in:

Supporting Multiple Quality of Service Options with High Perfomance Groupware.

Technical Report CS96-3, Institute of Computer Science, The Hebrew University of Jerusalem, March 1996

Postscript version: ps, ps.gz, Israel mirror site: ps.gz.

Last modified: Mon Jul 1 14:36:15 EDT 2002