Access protection for fairness in a distributed queue dual bus metropolitan area network

The access protection and priority control (APPC) mechanism in a distributed-queue dual-bus metropolitan area network (MAN) is presented. The basic version of the APPC mechanism ensures that the bandwidth allocated to each station is kept in known limits, independently of traffic load conditions. Moreover, under heavy loads, each station sees the common channel as a synchronous channel with fixed bandwidth. Under no circumstances is the available bandwidth wasted. The mechanism does not impose signaling overheads as compared to other algorithms proposed for the dual bus MAN