A testbed for token ring networks

The author describes a testbed based on a 4-Mb/s ISO 8802/5 token-ring network and consisting of a traffic generator subsystem in each network station and a distributed monitor system with centralized control and decentralized measurement. Dedicated hardware clocks in each station provide accurate global time information. The author presents examples of user-related performance measurement. Comparing previously published analytical results with these measurements reveals that implementation-specific characteristics strongly influence the performance observed by a user. An essential result, shown by measurements on priority operation of the network, is that for a small number of stations the differences in service between priority and nonpriority traffic predominantly occur at very high network loads.<
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