  Input buffered switches with Virtual Output Queueing (VOQ) can be unstable
when presented with unbalanced loads. Existing scheduling algorithms, including
iSLIP for Input Queued (IQ) switches and Round Robin (RR) for Combined Input
and Crossbar Queued (CICQ) switches, exhibit instability for some schedulable
loads. We investigate the use of a queue length threshold and bursting
mechanism to achieve stability without requiring internal speed-up. An
analytical model is developed to prove that the burst stabilization protocol
achieves stability and to predict the minimum burst value needed as a function
of offered load. The analytical model is shown to have very good agreement with
simulation results. These results show the advantage of the RR/RR CICQ switch
as a contender for the next generation of high-speed switches.
