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Support for PIR and CIR on MPCs
On MX Series devices using MPCs, CIR and PIR are supported at the queue level with class-of-service (CoS) schedulers. Use three rates, transmit-rate, shaping-rate, and excess-rate, which can be configured simultaneously, and use the excess-priority statement with excess-rate to manage the bandwidth in the excess region between CIR and PIR, as follows:
- excess-rate—Use to configure the percentage of excess bandwidth traffic that should go into the queue in the excess region.
- shaping-rate—Use to configure the maximum bandwidth usage, which sets the PIR.
- transmit-rate—Use to configure the minimum bandwidth allocated to a queue, which sets the CIR.
- excess-priority—Use to configure the priority of excess traffic in a scheduler as low, medium-low, medium-high, or high.
Support for PIR and CIR on DPCs
On devices using enhanced queuing DPCs, CIR and PIR are not supported at the queue level. PIR on these devices is supported by using the rate-limit statement. You can achieve an effect similar to CIR and PIR at the queue level by combining tricolor policers with rate-limit and drop profiles. You use the tricolor policers to enforce the CIR and PIR, by configuring the drop profiles to drop the yellow packets (packet loss priority (PLP): medium-high) before the green packets (PLP: low).
You can create a strict-high priority queue running at the same time as several high priority queues on all of the DPCs (including those with enhanced queuing and those without enhanced queuing). However, you cannot do this on devices using IQ2 PICs.
For more information, see MX Series Interface Module Reference