New low-level flow control strategies for fiber optic token rings

Congestion due to the speed mismatch in hierarchical communication systems in which conventional local area networks are interconnected by high-speed local area networks operating at 100 Mb/s is investigated. Results of a performance analysis of three low-level flow-control strategies are presented for an FDDI (fiber distributed data interference) backbone environment. The strategies operate at the MAC (medium access control) layer and have been evaluated with respect to packet loss at the destination. The three strategies yield almost identical results for the same values of wait and RBO (risk of buffer overflow) and reduce packet loss significantly when compared to pure FDDI. The remaining very low percentage of packet loss can be handled by conventional end-to-end flow control strategies