Department Of Mathematics, IIT Roorkee,Roorkee,India
In this paper we study two echelon multi-server tandom queueing systems where customers arrive according to a poisson process with two different rates. The service rates at both echelons are independent of each other. The service times of customers is assumed to be completed in two stages. The service times at each stage are exponentially distributed. At the first stage, the customers may balk (i.e. reject to join the waiting line) when all servers are busy. The higher echelon has a limited buffer space. The steady state queue size distribution has been obtained for both stages. We investigate the properties of a Hessenberg mat rix which is required for the complete specification of the generating function for ready use.