Scalable redundant switch fabric architecture

Abstract

A high-speed router and method for operation of the core of such a router are disclosed. The disclosure describes routing packets from core input ports to core output ports by aggregating or queuing packets at router core ingress ports in queues designated for common router core egress ports. A scheduler selects a set of queues, up to one per ingress port, for switching through the router core at each epoch (an epoch is a time slice). When the epoch for a given set of queues arrives, data from each queue is stranded, with one strand sent to each of multiple switch fabric cards. The switch fabric cards operate in parallel to switch the strands from that queue to a common egress port (as configured by the scheduler), where the strands are recombined to reconstruct the original queue data. This architecture can be made fault tolerant, can be made to degrade gracefully when one or more switch fabric cards goes down, and can support increased traffic simply by expanding the number of switch fabric cards. Scheduling for the router core is greatly simplified as compared to a core that switches on a packet-by-packet or cell basis, which also allows higher traffic loads.