A new enhanced renegotiation scheme for FDDI

The fiber data distributed interface (FDDI) is a 100 Mbps token ring network. The FDDI protocol is based on the timed token access protocol which provides dynamic adjustment of the load offered to the ring. This is done by setting a specific Target Token Rotation Time (TTRT) which provides a guaranteed upper bound on the interval between successive token arrivals at a station. The paper describes an enhanced renegotiation scheme for FDDI, which allows the TTRT to be automatically renegotiated. The TTRT can be adjusted frequently as and when the access time requirements of synchronous traffic changes, and also as and when synchronous traffic enters and/or leaves the network. The results show that better network throughput performance can be achieved under the new renegotiation scheme