Parallel Packet Switching Using Multiplexors with Virtual Input Queues

Parallel Packet Switches (PPS) use internal, parallel switch planes that operate at less than line speed. A PPS can scale-up to faster line speeds than a single-plane switch can. Load balancing between planes and providing QoS to flows are open problems. We investigate the performance of a new “VIQ PPS” that distributes cells or variable-length packets to planes and uses multiplexors with virtual input queues (VIQ). A VIQ at an output multiplexor consists of one FIFO queue for each input. Simulation is used to evaluate the performance of a 10-Gbps VIQ PPS that contains ten 1Gbps switch planes. It is found that at high offered loads the mean delay of a VIQ PPS switch is lower than that of a single-plane iSLIP switch. For unbalanced loads, the VIQ PPS demonstrates stability where an iSLIP switch is unstable. Especially promising results are shown for VIQ PPS native switching of variable-length Ethernet packets.