Performance Evaluation of Input Queued Buffered Sparse-Crossbar Packet Concentrators

In this paper, we study the performance of packet concentrators with input queueing. A recent concentrator model given by Gündüzhan and Oruç considers packet concentrators with different input and output packet rates and gives a minimum crosspoint complexity construction for buffered sparse crossbar concentrators. We use this model as a basis for the performance evaluation of concentrators which queue packets at the inputs and have different input and output packet rates. It is shown that for input queueing, with constant size packets and independent batch arrivals, the best performance can be represented by a GI/D/c queueing system. Using this result we provide explicit solutions for the probability distribution of queue occupancy and packet delay for binomial packet arrivals. Good tail approximations for quick calculations of buffer size and packet delay for a given probability of packet loss are also given.