A versatile packet multiplexer for quality-of-service networks

A novel packet multiplexing technique, called rotating-priority-queues (RPQ), is presented which exploits the tradeoff between high efficiency, i.e., the ability to support many connections with delay bounds, and low complexity. The operations required by the RPQ multiplexer are similar to those of the simple, but inefficient, static-priority (SP) multiplexer. The overhead of RPQ, as compared to SP, consists of a periodic rearrangement (rotation) of the priority queues. It is shown that queue rotations can be implemented by updating a set of pointers. The efficiency of RPQ can be made arbitrarily close to the highly efficient, yet complex, earliest-deadline-first (EDF) multiplexer. Exact expressions for the worst case delays in an RPQ multiplexer are presented and compared to expressions for an EDF multiplexer.