Network Egress 16-Priority Scheduling

The adapter cards and ports that support 16-priority scheduling for network egress traffic are listed in Table: Scheduling Modes Supported by Adapter Cards and Ports at Network Egress. This type of scheduling takes into consideration the traffic’s profile type and the priority of the CoS queue that the traffic is coming from.

Packets less than or up to the CIR are scheduled as in-profile. Packets that arrive at rates greater than the CIR, but less than the PIR, are scheduled as out-of-profile. Eight CoS queues in total are available for packets to go through.

In-profile traffic is exhaustively transmitted from the queues, starting with the highest-priority CoS queue. A strict priority is applied between the eight CoS queues. If a packet arrives at a queue of higher priority than the one being serviced, the scheduler services the packet at the higher-priority queue as soon as it finishes servicing the current packet.

Once all the in-profile traffic is transmitted, the out-of-profile traffic is transmitted, still maintaining priority of the queues. If an in-profile packet arrives and the scheduler is servicing an out-of-profile packet, the scheduler finishes servicing the out-of-profile packet and then immediately services the in-profile packet.

The order of priority in the default configuration is as follows:

• CoS-8 in-profile traffic

• CoS-7 in-profile traffic

• CoS-6 in-profile traffic

• CoS-5 in-profile traffic

• CoS-4 in-profile traffic

• CoS-3 in-profile traffic

• CoS-2 in-profile traffic

• CoS-1 in-profile traffic

• CoS-8 out-of-profile traffic

• CoS-7 out-of-profile traffic

• CoS-6 out-of-profile traffic

• CoS-5 out-of-profile traffic

• CoS-4 out-of-profile traffic

• CoS-3 out-of-profile traffic

• CoS-2 out-of-profile traffic

• CoS-1 out-of-profile traffic