This paper deals with a retrial queueing system with a finite number of homogeneous sources of calls and a single non-reliable server, which means that the server is subject to random breakdowns depending on whether it is busy or idle. The failure of the server may block or unblock the systems’s operations and the service of the interrupted request may be resumed or the call can be transmitted ...

This paper studies the N policy M/G/1 queue with server vacations; startup and breakdowns, where arrivals form a compound Poisson process and service times are generally distributed. The server is turned off and takes a vacation whenever the system is empty. If the number of customers waiting in the system at the instant of a vacation completion is less than N, the server will take another vaca...

In this paper, we study an M/M/2 queueing system with balking and two heterogeneous servers, Server 1 and Server 2. Customers arrive according to a Poisson process and form a single waiting line. Two parallel servers provide heterogeneous exponential service to customers on a firstcome first-served basis. It is assumed that Server 1 is perfectly reliable and Server 2 is subject to breakdowns. F...

In many industrial situations, machines are subjected to random breakdowns. In this paper, we consider the asynchronous vacation policy for the multi-server machine repair problem with server breakdown and two types of spares. According to this policy, when a certain number of servers become idle at a service completion instant, the servers will take an asynchronous vacation of random length to...