Peak information rate

The peak information rate (PIR) defines the maximum rate at which packets are allowed to exit the queue. The PIR does not specify the maximum rate at which packets can enter the queue; this is governed by the ability of the queue to absorb bursts. The actual transmission rate of an egress queue depends on more than just its PIR. Each queue is competing for transmission bandwidth with other queues. Each queue, PIR, CIR, and the relative priority and weight of the scheduler serving the queue, all combine to affect the ability of a queue to transmit packets.

When defining the PIR for a queue, the value specified is the administrative PIR for the queue. The user has some control over how the administrative PIR is converted to an operational PIR when the hardware does not support the exact CIR and PIR values specified. See Adaptation rule for queues for more information about the interpretation of the administrative PIR.

The PIR of the queue is configurable under the different QoS policies that provide the option to configure the queue parameters — example under access port policies, network queue policies, and so on.