End-to-End Scheduling in Real-Time Packet-Switched Networks

This paper presents the budgeted-weighted-round-robin (BWRR) algorithm for scheduling the transmission of hardreal-time messages in a packet-switched network. The BWRR algorithm provides a bound on the worst case delay of a message through the network. In addition, with the BWRR algorithm, the necessary buffer space at each switch is predictable and can be fixed at system configuration time. The per switch delay and required buffer space provided by the BWRR algorithm are significantly less than those provided by previous methods. The BWRR algorithm has a simple hardware implementation and admission test, and it does not require a global clock or any explicit flow control messages. It can achieve high utilization of the network under most practical scenarios and reacts predictably under transient overloads.