Semantically Reliable Multicast: Definition, Implementation and Performance Evaluation.

J. Pereira, L. Rodrigues and R. Oliveira

This report will be published in IEEE Transactions on Computers, Special Issue on Reliable Distributed Systems, (Vol 52, Nb. 2), pp. 150-165, February 2003.


Semantic reliability is a novel correctness criterion for multicast protocols based on the concept of message obsolescence: A message becomes obsolete when its content or purpose is overwritten by a subsequent message. By exploiting the obsolescence, a reliable multicast protocol may drop irrelevant messages to find additional buffer space for new messages. This makes the protocol more resilient to transient and even, in some cases, to permanent performance perturbation of multicast group members.

This paper describes our experience in developing a suite of semantically reliable protocols. It provides a synthetic but comprehensive overview of our previous work in this area. The paper extends previous work by additionally presenting performance figures obtained with our running implementation. The data obtained experimentally is compared with the analytic and simulation models developed previously. This comparison allows us to extract lessons about the validity of these models. Finally, the paper reports the application of our prototype to distributed multi-player games.

Not available online

Luís Rodrigues