A fully adaptive routing algorithm for dynamically injured hypercubes, meshes and tori

Unicast_V is a progressive, misrouting algorithm for packet or virtual cut-through networks. A progressive protocol forwards a message at an intermediate node if a nonfaulty profitable link is available and waits, deroutes, or aborts otherwise. A misrouting protocol uses both profitable and nonprofitable links at each node; thus, a message can move farther away from its destination at some steps. Unicast_V is simple for hardware implementation, requires a very small message overhead, and makes routing decisions by local failure information only. However, it is claimed to be partially adaptive and to be able to tolerate static faults in hypercubes only. In this paper, we uncover some new features of Unicast_V: 1) It is fully-adaptive, 2) it also applies to meshes and tori, and 3) it can tolerate dynamic faults by careful implementation. In addition, we also provide bounds on the performance of the algorithm.