Evaluation of a Mesh of Clos wormhole network

The pursuit of high connectivity in network design for multicomputers is often complicated by wiring constraints, resulting in a trade-off between efficiency and realizability. The Mesh of Clos topology addresses this trade-off by combining a multistage network with a mesh network. In this paper, a simulation study is presented in order to evaluate wormhole-routed Mesh of Clos communication networks. It is shown that this type of network can substantially reduce contention in comparison with flatter mesh networks. Furthermore, we found that increasing the number of flit-buffers on router devices does not necessarily lead to improved communication performance. For some application loads it may even result in a degradation of performance.