ABSTRACT
SUMMARY It is known that in a nonblocking packet switch with input queueing, head-of-line (HOL) blocking affects significantly the maximum throughput of the packet switch. To alleviate the HOL blocking effect, a window policy has been proposed in that each input queue can scan up to a fixed number of packets (called the window size) to select for transmission on the outputs. However, the performance of the window policy has never been precisely characterized. In this paper, we use a closed queueing network model to characterize the performance of the packet switch with window policy. We obtain explicit closed-form formulae for the maximum throughput of the packet switch as a function of the window size. Both balanced and imbalanced traffic patterns are discussed. The formulae can easily determine the effectiveness of the window policy.
