Assigning customers to two parallel servers with resequencing

In this letter, we consider the resequencing delay characteristics of a system with two heterogeneous servers serving a single queue with Poisson packet arrivals. An ordered delivery of packets is guaranteed at the receiver, hence packets arriving out of order suffer additional resequencing delay. We introduce the concept of threshold policies with variable routing positions and obtain analytical expressions for the end-to-end delay. With numerical examples we show that some improvement is obtained in the end-to-end delay values with variable routing position policies over fixed position routing policies. Further, initial simulation studies seem to indicate that this observation is true even with bursty arrivals.