Time constrained applications on a LAN-a performance study

The performance of network protocols for time-constrained applications on a local area network (LAN) is evaluated. The evaluation is based on a reduced protocol architecture consisting of the physical (layer 1), data link (layer 2), and application (layer 7) layers. The performance measure of interest is the frequency with which the confirmed delivery of a message is achieved within a given time constraint. Since confirmed delivery relies on reliable data transfer, a relevant question is at which layer should the error recovery function reside. Two strategies are examined; they correspond to performing error recovery in layers 2 and 7, respectively. Analytic results on their performance difference are derived. The strategy with error recovery in layer 2 is investigated further, and simulation results on its performance characteristics are presented.<>