Abstract: In standard token-based LANs (e.g., FDDI, Token Ring) an equal share of the ring bandwidth is made available to each node. Certain nodes (e.g., bridges, routers, servers) require a larger representation (bandwidth) than other nodes. A surrogate (bridge/router) node is presented which achieves this in a standard compliant manner. The bridge/router may serve as a surrogate on each ring representing multiple stations from the other ring. The multiplicity of stations is adjusted either statically or dynamically to provide sufficient added bandwidth to the surrogate to reduce delay and packet loss characteristic of the conventional single station bridge or router. The increased bandwidth utilization and FDDI ring performance resulting from the implementation of this invention is transparent to the individual stations and the ring in a way that is advantageous to both single media and multimedia usages within defined network local and non-local areas.

Abstract: A method and apparatus allow the interoperability of a token ring packet data network managed by the timed-token protocol (FDDI-I) and a TDM network (FDDI-II) with a given bandwidth allocation assigned to the packet data timed-token protocol. Only a single token is used, and the delay and loss of packets which cannot be transmitted on account of limited bandwidth is reduced. The flow of packets into the slots of the communications ring following the TDM protocol is controlled by varying the amount of time in which the token is held by the interface between the two communication rings. That is, the time in which the token is held by the interface is a function of the number TDM slots allocated to the transmission of packet data.