A Best-Effort Communication Protocol for Real-Time Broadcast Networks

In this paper, we present a best-effort communication protocol called AEA, that seeks to maximize aggregate application benefit and deadline-satisfied ratio of asynchronous real-time distributed systems that use CSMA/DDCR broadcast networks. AEA considers an application model where end-to-end timeliness requirements of trans-node application tasks are expressed using Jensen's benefit functions. Furthermore, the protocol assumes that the application is designed using CSMA/DDCR feasibility conditions that is driven by a "best" possible estimate of upper bounds on message arrival densities that is possible at design-time. When such design-time postulations get violated at run-time, AEA directs message traffic so that messages that will increase applications' aggregate benefit are only transmitted, buffering others, until such time when the workloads respect their design-time postulated values. To study the performance of AEA, we consider a previously studied algorithm called REA * as a baseline algorithm. Our experimental results indicate that AEA yields higher aggregate benefit and higher deadlinesatisfied ratio than REA * when message arrival densities increase at faster rates or at the same rates as that of process execution latencies due to the dynamics