1-2hit |
Xuesong TAN Shuo-Yen Robert LI
The cascade of two baseline networks in tandem is a rearrangeable network. The cascade of two omega networks appended with a certain interconnection pattern is also rearrangeable. These belong to the general problem: for what banyan-type network (i.e., bit-permuting unique-routing network) is the tandem cascade a rearrangeable network? We relate the problem to the trace and guide of banyan-type networks. Let τ denote the trace permutation of a 2n2n banyan-type network and γ the guide permutation of it. This paper proves that rearrangeability of the tandem cascade of the network is solely determined by the transposition τγ-1. Such a permutation is said to be tandem rearrangeable when the tandem cascade is indeed rearrangeable. We identify a few tandem rearrangeable permutations, each implying the rearrangeability of the tandem cascade of a wide class of banyan-type networks.
Akira FUNAHASHI Toshihiro HANAWA Hideharu AMANO
Multistage Interconnection Networks (MIN) with multiple outlets are networks which can support higher bandwidth than those of nonblocking networks by passing multiple packets to the same destination. Fault recovery mechanisms are proposed for two of such networks (TBSF/PBSF) with the best use of their inherent fault tolerant capability. With these mechanisms, on-the-fly fault recovery is possible for multiple faults on switching elements. For the link fault, the networks are reconfigured after fault diagnosis, and the network is available with some performance degradation. The bandwidth degradation under multiple faults on link/element is analyzed with both theoretical models and simulation. Through the analysis, F-PBSF shows high fault tolerance under high traffic load and low reliability by using 3 or more banyan networks.