Fault-tolerant routing in a class of double loop networks

Double-loop networks have a higher connectivity and therefore a higher potential for fault tolerance than single-loop networks. The authors present distributed routing schemes that fully utilize that fault-tolerance potential, and that are applicable in particular to a specific class of double-loop networks, characterized by a forward loop connecting all the adjacent nodes, and a backward loop connecting nodes separated by a distance that depends on N, the number of nodes. A nice feature of these schemes is that for a given node, only local knowledge on the status of the neighboring nodes and links is required. Yet the schemes detect faulty nodes and links and adapt to the situation, so that a packet will eventually reach its destination, if there exists a path. A simulation has shown that the average overhead resulting from the schemes, in terms of number of hops, does not exceed 17%, for values of N around 16