A fluid flow tracking arbiter for input buffered ATM switch with heterogeneous port bandwidth

The problem of designing a weighted arbiter for an input buffered ATM switch with heterogeneous port bandwidths and which supports multiple classes of service is considered. A novel approach to design arbiters is proposed and illustrated with an application for a small (32 × 32) input buffered ATM switch with two classes of services: the high priority guaranteed service class and a low priority overbookable service class. The GPS fairness criteria, which was proposed in A. K. Parekh and R. G. Gallager (June 1993) for service schedulers, is generalized for the arbitration problem and the proposed fluid flow tracking arbiter (FFTA) satisfies the fairness criteria. In the FFTA, the requests to the arbiter are treated both as discrete and as fluid quantities. The arbitration decisions are made by simulating a fluid flow of requests and grants are issued so as to minimize deviation of the discrete requests from their fluid counterparts.