Patent ID: 8274974
Filing Date: 2012-09-25
Classification: H04L

Abstract:
1. A method for propagating quality of service across a switched backplane comprising: setting a minimum rate at which packets are dequeued from ingress queues to backplane ports for maintaining a quality of service, the backplane ports connecting to blades on the switched backplane using a backplane channel; determining that an egress queue mapped to a backplane port is congested, upon receiving by an ingress queue manager a notification from an egress queue manager of congestion on the egress queue in a congestion message identifying the congested egress queue, the congestion message comprising: determining a destination blade of the backplane port to which the congested egress queue is mapped; maintaining the rates of dequeuing packets from the ingress queues to the backplane ports at or above the minimum rate while reducing a rate of enqueuing packets to all egress queues mapped to any backplane ports connecting to the destination blade of the backplane port to which the congested egress queue is mapped, including the rates of ingress queues residing on different blades from the egress queues for which the rate of enqueuing packets was reduced; determining that the previously congested egress queue is no longer congested; delaying resumption of a normal rate of enqueuing packets to all egress queues mapped to any backplane ports connecting to the destination blade of the backplane port to which the congested egress queue is mapped until determining that the previously congested egress queue is no longer congested and that all egress queues mapped to backplane ports connecting to the destination blade are not congested upon receiving a notification in an ingress queue manager from an egress queue manager to resume a normal rate of enqueueing packets for all egress queues mapped to backplane ports connecting to the destination blade, including receiving the notification in ingress queue managers for the ingress queues residing on different blades from the egress queues for which the rate of enqueuing packets was reduced.