Fault tolerant routing using improved safety vectors

The safety vector [12] of a node in an n-cube, is a vector of n bits, each bit being a zero or 1. A value 1 in the k^th bit of a node´s safety vector guarantees a fault-free path to any node at Hamming distance k from it. In [13], it was shown that use of extended safety vector gives better performance at the cost of some extra computation. In this paper we have made a modification of the safety vector, and called it improved safety vector. Here, each element of the vector can have 4 possible values, 3,2,1, and 0. Experimental results show that improved safety vector gives better performance in hypercube. Unlike extended safety vector, improved safety vector leads to a better performance compared to safety vector even in the absence of link faults.