Input queue packet switch architecture and queue service discipline

Abstract

A packet switching node is described according to which a plurality of packets queued in an input queue are taken into account when selecting a packet for forwarding via a free output port. Accounting for multiple queued packets reduces the probability that an output port will remain idle and increases the probability that each input queue will be serviced despite blocking packet forwarding due to contention. Also described is the process of enqueuing and dequeuing packets from input queues, each input queue having associated therewith a plurality of head-of-line registers pointing to a corresponding sequence of head-of-line queue entries. Enqueueing ensures that the correct head-of-line registers point to the sequence of head-of-line queue entries in turn. Service each input queue dequeue entry in order, and dequeue ensures reordering of head of queue pointers. Advantages are gained from reducing the likelihood of output ports remaining idle while increasing the likelihood of servicing input queues, thus reducing the adverse effects of contention and increasing packet throughput.

Description

technical field [0001] The present invention relates to the packet switching node structure, and specifically relates to the input queuing packet switching node structure and queue service rules. Background technique [0002] Much of the packet-switching infrastructure in use today operates on the basis of store-and-forward packet processing rules. The commonly used Internet Protocol (IP) is an example of a packet transport protocol following the store-and-forward rule. Each IP packet has a header portion and a payload portion of variable length. Deterministic resources include: packet transmission bandwidth on communication links interconnecting packet switching nodes, packet storage on packet switching nodes, and packet processing bandwidth on packet switching nodes. [0003] Assuming that sufficient storage is available at the packet switching nodes, packets are transmitted over the interconnecting links, which are subject to the transmission bandwidth available on the ...

AI Technical Summary

Problems solved by technology

[0008] While other variations of the packet-switched fabrics described above have been the subject of intense research and development, a review of the literature shows that simple packet-switched fabrics such as input queuing structures and output queuing structures suffer from low packet throughput performance, while virtual output queuing structures such as Queue-structured complex packet-switched structures, resulting in huge development, maintenance and overhead costs due to the high complexity of their implementation

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