A 2-LAYER CONGESTION CONTROL PROTOCOL FOR BROAD-BAND ISDN

In this paper, we present a new, effective connection-oriented congestion control protocol for B-ISDN. The protocol employs the traffic viewpoint hierarchical design approach and is implemented by a two-layer scheme at the call and cell layers. The call layer handles call admission (denial) and provides shortest path connection routing when a call is admitted, while the cell layer allocates switch input buffer space for each traffic type according to each type's cell loss probability grade-of-service requirement. There is a direct interaction between the two layers in processing a connection request. A discrete-time queueing system with geometrically distributed service time and state-dependent Markov modulated Bernoulli process (MMBP) arrivals is established to model heterogeneous networking environments for this protocol and an analytical solution is developed for this queueing system. Numerical results obtained by both analysis and simulation show that the protocol can reduce network congestion as input traffic rates approach switch capacity and, thereby, increase network utilization relative to that possible in the absence of congestion control.