A Versatile Packet Multiplexer for Quality-of-Service Networks

A novel packet multiplexing technique, called Rotating-Priority-Queues (RPQ), is presented which exploits the tradeo between high e ciency, 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 ine cient, 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 e ciency of RPQ can be made arbitrarily close to the highly e cient, 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.