US Patent 7539199 Switch fabric scheduling with fairness and priority consideration

A scheduler for a packet switch in a high-speed network. In various embodiments, switch throughput and fairness is improved by operating on request data before arbitration. Other embodiments further include forms of weighted round robin (“WRR”) allocation of output bandwidth prior to arbitration. In various embodiments, the WRR allocation is performed at more than one level. For example, an output applies WRR allocation to all inputs requesting access to that output. In addition, an input applies WRR allocation to multiple classes of data on that input.