NEW MULTIPLE ACCESS PROTOCOL FOR LOCAL AREA NETWORKS.

Abstract

A description is given of a new multiple-access protocol for local area networks. It is basically a hybrid of carrier-sense multiple access with collision detection (CSMA/CD) and broadcast recognition with alternating priorities (BRAP). It is well known that CSMA/CD, as well as other contention-based protocols, works well under the condition of light load but message collisions will affect system performance when the channel becomes heavily loaded. On the other hand, collision-free protocols have longer delays at low load but the efficiency will improve as the load increases. The authors propose a new protocol which combines the Ethernet protocol and a collision-free reservation-based protocol. Performance models are developed for the Ethernet protocol, as well as for the proposed protocol. It is found that the new protocol gives better performance under a wide range of scenarios.