Capacity testing a HYPERchannel-based local area network

Using a hardware monitor, the capacity of a mature (over 10 years old), heavily loaded (5 Cray supercomputers, 3 Ethernet gateways, 13 terminal concentrators, 5000 terminal, 40 node) two-trunk, HYPERchannel-based, high-data-rate local area network was tested. Results indicate that the current load could be intensified by 40% before the network reaches saturation. As the load approaches saturation, overly persistent, low-level protocols begin thrashing, effectively destabilizing the network and destroying much of its potential capacity. The steps needed to extend its lifespan and improve its performance under heavy loads are recommended