Normally, a scheduler policy contains rates that indicate packet-based accounting values. When the children associated with the policy are operating in frame-based accounting mode, the parent schedulers must also be governed by frame-based rates. Because either port-based or service-based virtual scheduling is required for queue or policer frame-based operation, enabling frame-based operation is configured at either the scheduling policy or aggregate rate limit command level. All policers and queues associated with the policy or the aggregate rate limit command inherit the frame-based accounting setting from the scheduling context.
When frame-based accounting is enabled, the policer and queue CIR and PIR settings are automatically interpreted as frame-based values. If a SAP ingress QoS policy is applied with a queue PIR set to 100 Mb/s on two different SAPs, one associated with a policy with frame-based accounting enabled and the other without frame-based accounting enabled, the 100 Mb/s rate is interpreted differently for each queue. The frame-based accounting queue adds 20 bytes to each packet received by the queue and limits the rate based on the extra overhead. The packet-based accounting queue does not add the 20 bytes per packet and therefore allows more packets through per second. Packet byte offset settings are not included in the applied rate when frame-based accounting is configured; however, the offsets are applied to the statistics.
Similarly, the rates defined in the scheduling policy with frame-based accounting enabled are automatically interpreted as frame-based rates.
The port-based scheduler aggregate rate limit command always interprets its configured rate limit value as a frame-based rate. Setting the frame-based accounting parameter on the aggregate rate limit command only affects the policers and queues managed by the aggregate rate limit and converts them from packet-based to frame-based accounting mode.