Congestion avoidance in broadband ISDN

The authors present a congestion avoidance scheme that is simple yet effective. This scheme basically exercises access control for the incoming calls. In this scheme, an incoming call is accepted only if its resource requirement is not more than a certain predefined percentage of the remaining resources at the intermediate points of a BISDN (broadband integrated services digital network). The authors simulate this scheme for a simple network and present results in terms of blocking probabilities as the arrival rates of different kinds of calls are varied. Some results are shown in terms of effects of varying the threshold on the blocking probabilities. Some of the effects are depicted in terms of delay histograms for different situations. Generally, the results show that the calls with higher bandwidth requirements are affected the most as compared to the calls that have lower bandwidth requirements. The model developed is useful in the design of BISDN that can handle a wide variety of traffic characteristics of different applications