Flexible bandwidth allocation in terabit packet switches

Switches with input buffers can potentially provide high capacity, because they do not involve multiplexing at output ports, and inputs can operate at high bit-rates. We have previously proposed an algorithm for packet scheduling in high-capacity switches, termed round-robin greedy scheduling (RRGS). RRGS completely removes head-of-line (HOL) blocking at terabit capacity. However, RRGS cannot provide arbitrary bandwidth shares to input-output pairs. We propose a simple extension of RRGS, termed weighted RRGS (WRRGS), which can flexibly share the bandwidth of any output among the inputs at terabit switching capacity. We prove that WRRGS can share at least 50% of the total switch capacity. It exploits the fact that RRGS finds a maximal matching between inputs and outputs.