Publisher Summary This chapter focuses on the performance evaluation of interconnection networks along with the analysis of the effect of network traffic and the impact of many design parameters. At first glance, it may seem that spending time in improving the performance of the interconnection network hardware is useless. However, for very long messages, communication latency is still dominated by the network hardware latency. In this case, networks with a higher channel bandwidth may achieve a higher performance. On the other hand, messages are usually sent by the cache controller in distributed, shared-memory multiprocessors with coherent caches. In this architecture there is no software messaging layer. Therefore, the performance of the interconnection network hardware is much more critical. Network load has a very strong influence on performance. In general, for a given distribution of destinations, the average message latency of a wormhole-switched network is affected by network load than by any design parameter, provided that a reasonable choice is made for those parameters. Therefore, modeling the network workload is very important. Most performance evaluation results have only considered a uniform distribution of message destinations.