Priority-based totally ordered multicast

L. Rodrigues, A Casimiro, and P. Veríssimo

Selected sections of this report were published in the Proceedings of the 3rd IFAC/IFIP workshop on Algorithms and Architectures for Real-Time Control (AARTC'95). Ostend, Belgium, May 1995.


The replicated state-machine approach is a general paradigm to implement fault-tolerant services that is particularly useful in real-time control applications. A totally ordered multicast protocol is a well-known method to enforce replica determinism in this approach. The paper presents an algorithm to provide a totally ordered multicast delivery service that takes priorities into account. The algorithm enforces the inter-replica coordination required to guarantee that high priority messages can be delivered before queued low priority messages that have not been delivered. The algorithm as been implemented as a variant of a protocol designed for local-area networks.

Also available extended report (gzip postscript), (pdf).

Luís Rodrigues