A vacation queueing model with service breakdowns

In this paper we analyze a multiple-vacation queueing model, where the service station is subject to breakdown while in operation. Service resumes immediately after a repair process, and a vacation starts at the end of each busy period. Arrivals follow a Poisson process with rates depending upon the system state, namely, vacation, service, or breakdown state. The repair times, times to breakdown following a repair or vacation, uninterrrupted service times, and length of each vacation follow exponential distributions. Some results are also obtained when vacation, service, and repair times follow phase-type distributons. (C) 2000 Elsevier Science Inc. All rights reserved.