Traffic performance for a time-out scheme communication system

Motivated by performance evaluation of a computer communication system, we consider a renewal input, general service time, single-server, and infinite-capacity queuing system with generally distributed time-out threshold. We obtain two moment approximate formulas for the mean system performance measures (including the mean number of customers in the system and the mean response time) by using the diffusion process with the reflecting barrier. Our tele-traffic model includes the standard G/G/1 system without time-out scheme as a special case. From performance comparisons between our diffusion approximation and simulation results, we also provide refining formulas.