New adaptive routing algorithm for extended generalized fat trees on-chip

Network topology and routing algorithm are the issues that have the most significant effect on the performance of packet-switched networks. The throughput of fat trees can be considerably improved by connecting the topmost switches together and by replacing the most usually used minimal (shortest-path) routing algorithms with a new turn back when possible (TBWP) algorithm. This paper shows how the TBWP can also be used in extended generalized fat trees (XGFT) after the modification. The XGFTs are one version of fat trees with improved scalability. Simulation results are also presented so as to show the improved throughput of the modified XGFTs when the TBWP is used in them. This paper concerns also issues related to scalability.