On the Equivalence of IEEE 802.4 and FDDI Timed Token Protocols

Two timed token protocols, the IEEE 802.4 and FDDI (fiber distributed data interface), are considered. Although IEEE 802.4 and FDDI have similar protocol rules, the different method of measuring the duration of the generic token rotation has imposed separate analyses for the two protocols. Presented is a general proof of equivalence between IEEE 802.4 and FDDI networks, where both consist of queues belonging to two priority classes. Having proved this equivalence, it is possible to extend results formally demonstrated for one protocol to the other. In particular, the results regarding the bounds on mean and maximum token rotation time derived for FDDI by Sevcik and Johnson (1987) can also be extended to IEEE 802.4 networks