Bridging the gap between application semantics and group communication protocols

Group communication protocols have received great attention over the past years. From a practical viewpoint, several middleware systems have implemented the group communication abstraction; from a theoretical viewpoint, a sound theory underlying group communication has been developed and minimal solvability conditions have been identified. So far, however, group communication protocols have not taken application semantics into account, and, in some cases, the guarantees offered by group communication protocols are stronger than necessary for application correctness. In this short paper, we claim that exploiting application semantics is a promising direction for future research on group communication protocols, and discuss Generic Broadcast, an example of a group communication protocol that allows applications to express their message ordering needs.