A slot-reuse protocol for rearrangeable dual-bus networks

In the near future, networks based upon the IEEE 802.6 metropolitan area network standard will become widespread. Eventually, networks of this type will be possible using both conventional point-to-point fiber and new photonic implementations. In both cases, it is possible to decouple the physical and logical topologies of the network yielding a rearrangeable bus. This capability magnifies the benefits of a media access protocol with destination slot release. In this paper, a media access protocol is introduced which provides destination slot release at each station. The REQPASS Protocol is a way of achieving fair bandwidth allocation in the presence of network overload conditions. REQPASS combines the request protocol with a slot release mechanism which permits request erasures on the reverse bus. A novel analytic model is introduced which accurately computes the mean queueing delay for individual stations. The success of the model is attributed to the fact that in a network with slot reuse, traffic independence approximations are more reasonable