A two-moment approximation for a buffer design problem requiring a small rejection probability

Abstract A useful model for buffer capacity design in communication systems is the single server queueing model with restricted accessibility where arriving customers are admitted only if their waiting plus service times do not exceed some fixed amount. A two-moment approximation for the buffer capacity in order to achieve a specific rejection probability is proposed for the case of Poisson arrivals and general service requirements. This approximation is a weighted combination of exact results for the special cases of deterministic and exponential service requirements where the weights use only the coefficient of variation of the general service requirement. Numerical experiments show an excellent performance of the approximation.