Redundant media mechanisms for dependable communication in token-bus LANs

The author presents a study of a redundant media implementation for an ISO 8802/4 token-bus local area network (LAN), consistent with the standard recommendations. The redundant media IEEE-802.4G-compatible interface is intended to provide high availability of network access in the presence of medium omission and stopping faults. A set of management rules and fault treatment operations is defined, together with lookahead medium failure detection, to limit overall omission degree to that of a single medium, and avoid unavailability because of medium failure. It is concluded that the proposed mechanism is completely general, and may be applied to plain 8802/4 LANs, i.e. Manufacturing Automation Protocol networks.<
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