A new transparent bridge protocol for LAN internetworking using topologies with active loops

This paper proposes a new transparent bridge protocol for LAN interconnection that considerably improves the performance of current standard IEEE-802.1D bridges. The current standard is based on the Spanning Tree (ST) algorithm and the most important restriction is that it cannot work when the topology has active loops. The new protocol (named OSR for Optimal-Suboptimal Routing) allows them. Therefore, strongly connected regular topologies, like torus, hypercubes, meshes, etc., as well as irregular topologies, can be used without wasting bandwidth. As loops imply alternative paths, the OSR protocol uses optimal routing or in the worst cases, suboptimal routing. The new protocol has been evaluated on highly connected regular topologies, like meshes. The results are compared with those of a network of the same size managed by the standard spanning tree protocol, showing the superior behavior of the OSR protocol