MAC address test protocol for a reconfigurable dual-ring local area network

The address of the ring local area network (LAN) station most be unique in the ring. This paper considers the distributed control‐type ring LAN with the configuration management function and proposes an MAC layer address test protocol, which can avoid the duplication of MAC addresses. In the ring LAN, the number of stations contained in the ring is increased or decreased by contraction or expansion of the ring. The duplication of addresses can occur due to the change of the stations, i.e., the set of MAC addresses. Consequently, the proposed system executes the duplicat ed address test being aligned to the ring connection of the station or the ring reconfiguration. the station executes the duplicated address test by the same protocol for various topologies of the ring LAN, such as the single ring, the simple dual ring, and the dual ring with the hierarchical star‐ring structure. By the proposed protocol, it is possible to construct the ring LAN so that the stations have an inherent MAC address no matter how the ring may be reconfigurated. The proposed algorithm is described by the finite‐ state machine (FSM), and a series of processing flows is shown for the address test accompanying the ring reconfiguration. the proposed protocol is included in the IEEE Recommended Practice for the duplicated address test in the dual‐ring LAN with the ring reconfiguration function.