Fault Tolerant Unicast Wormhole Routing in Irregular Computer Networks

For Networks with t+1 link disjoint spanning trees, we propose a fault tolerant deterministic and adaptive unicast wormhole routing technique which can tolerate up to 100% of all faults involving up to t link faults and high percentage of faults involving more than t links. This technique provides deadlock prevention with message delivery times that is almost identical to the case without fault tolerance. The proposed algorithm consists of two stages. At the first stage, we minimize the set of turns in the network graph, which are prohibited for deadlock prevention and fault tolerance. At the second stage, routing tables are constructed based on the set of prohibited turns that minimize average message path lengths for adaptive routing. Routing tables constructed this way produce a set of output ports sorted in ascending order in terms of the distance to the destination. To route the messages adaptively we select the next available shortest path to the destination. We also present results of simulation experiments for average delivery time for uniform traffic pattern and saturation points.