Virtual output queue allocation using dynamic drain bandwidth

摘要

In general, techniques are described for allocating virtual output queue (VOQ) buffer space to ingress forwarding units of a network device based on drain rates at which network packets are forwarded from VOQs of the ingress forwarding units. For example, a network device includes multiple ingress forwarding units that each forward network packets to an output queue of an egress forwarding unit. Ingress forwarding units each include a VOQ that corresponds to the output queue. The drain rate at any particular ingress forwarding unit corresponds to its share of bandwidth to the output queue, as determined by the egress forwarding unit. Each ingress forwarding unit configures its VOQ buffer size in proportion to its respective drain rate in order to provide an expected delay bandwidth buffering for the output queue of the egress forwarding unit.

主权项

1. A method comprising:
determining, by a network device, a change in a drain rate at which network packets are forwarded from a Virtual Output Queue (VOQ) of an ingress forwarding unit of the network device to an egress forwarding unit of the network device, wherein the VOQ comprises a logical queue that corresponds to an output queue of the egress forwarding unit, wherein a size of the VOQ comprises a portion of a logical size of the output queue, wherein the logical size of the output queue is divided among a plurality of VOQs of a plurality of respective ingress forwarding units that includes at least the ingress forwarding unit, wherein the drain rate of the VOQ is based on a respective drain rate for each of the VOQs of the plurality of respective ingress forwarding units that is forwarding network packets to the egress forwarding unit; and in response to determining the change in the drain rate, modifying, at the ingress forwarding unit, the size of the VOQ in direct proportion to the determined change in the drain rate.