International Business Machines Corporation

Lockheed Martin Corporation

Donald R Staddon, Jr

Jon F Hauris

Ronald A Bowen

Donald R Garris

A server, and a number of client stations interconnected by a token ring network, specifically an FDDI-II network. The FDDI-II ring is connected in a star-ring topology, with the server and the clients preferably connected to the network through a wiring closet, as is the usual practice for such a topology. The server has separate physical connections to the single FDDI-II ring with each physical connection to the ring providing access to a separate physical domain. This partitions the same ring into different physical domains, so that an increase in the total effective bandwidth of the network is achieved by the server reallocating the same isochronous bandwidth in each of the domains for reuse by the server. An allocation of bandwidth in an isochronous channel in one domain can be reused by the server in another physical domain.

Ring domains for bandwidth sharing

A flow control protocol is used to optimize the throughput on transmission opportunities without exceeding the allocated bandwidth in a Fiber optic Distributed Data Interface (FDDI) Local Area Network (LAN). The flow control protocol limits the number of flames that a station can chain together to a maximum number that insures that the station does not exceed its bandwidth allocation per Token opportunity. When this maximum number is reached, the current chain is placed in a first-in, first-out (FIFO) queue to await the next transmission opportunity. When a chain is enabled for transmission, subsequent flames are placed on a free standby chain, and this process continues until the maximum allowed number of frames is reached. By either chaining together fewer flames than the maximum number or continuing to the maximum number, the number of frames to be chained together in the current chain is optimized providing improved performance.

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Manassas, VA, United States of America

Donald R Staddon, Jr