Voq-based network switch architecture using multi-stage arbitration fabric scheduler

Abstract

A network switch capable of supporting cut-though switching and interface channelization with enhanced system performance. The network switch includes a plurality of ingress tiles, each tile including a virtual output queue (VOQ) scheduler operable to submit schedule requests to a fabric scheduler. Data is requested in unit of quantum which may aggregate multiple packets, which reduces schedule latency. Each request is associated with a start-of-quantum (SoR) state or a middle-of-quantum (MoR) state to support cut-through. The fabric scheduler performs a multi-stage scheduling process to progressively narrow the selection of requests, including stages of arbitration in virtual output port level, virtual output port group level, tile level, egress port level and port group level. Each tile receives the grants for its requests and accordingly sends request data to a switch fabric for transmission to the destination egress ports.