Schedulability analysis of multi-access protocols for distributed real-time systems

The class of online protocols which exhibit deterministic properties in spite of a lack of global knowledge are considered. Such protocols (e.g. tree protocols) yield computable bounds on the duration of collision resolution. The authors show that combining such deterministic properties with feasibility tests, such as those developed in real-time scheduling, permits the design of provably correct hard real-time protocols. The authors extend a centralized real-time problem to a decentralized context using the idea of extra cost. The applicability of the results is then illustrated with the CSMA-DCR (Ethernet with deterministic collision resolution) protocol, which is currently used in real settings.<>