Performance of FDDI under overload

The performance of the Fiber Distributed Data Interface (FDDI) under overload is studied. It is well known that, under overload, FDDI can settle into one of many recurrent sets of states. The idea of desirable and undesirable states is introduced. A desirable state is one where users share the capacity more or less equally in each token rotation. It is shown that the response times of interactive users are adversely affected if the system operates in an undesirable set of states. The waiting time of heavy users can be reduced by forcing the system to settle into the desirable states. Simple control mechanisms are proposed to ensure that the system settle into the desirable states