Stability of maximal size matching scheduling in input-queued cell switches

We consider cell-based switch architectures in which the speedup of the internal switching fabric is not large enough to avoid input buffering. These architectures require a scheduling algorithm to select at each slot a subset of input buffered cells which can be transferred towards output ports. The stability properties of maximal size matching (MSM) scheduling algorithms are studied in the paper, using analytical techniques primarily based upon Lyapunov functions. The main result of the paper is the proof that, for a wide class of MSM scheduling algorithms, stability is guaranteed by an internal switch speedup equal to two