Router QoS Input Policy to Perform DSCP-Based Drops Within AF4 Class

[Michael Mertens]

I have the need to create an Input policy on an ASR to drop DSCP traffic marked AF43 before AF42, Af42 before AF41 and AF41 before CS4 once when a certain bandwidth threshold is met; or simply to act on the drop probibility field for AF4 class. I want it on the input of the router since we're doing priority queuing on a modular QoS config on the output of the router. Since it's an input service-policy, I cannot do the bandwidth command on an input, so am looking for ideas on how to make the simpliest QoS config to: Drop all non-CS4 traffic in the AF4 class, once when 30 Mbps input rate is met.

Thanks for your input.

Mike.

[Joseph W. Doherty]

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Posting

Hmm, I believe what you want to accomplish, with an ingress policy, isn't possible (as you're limited to policing).

If it were for egress, you would shape all the traffic for your 30 Mbps, and if you went over the shape rate, and hense started to queue packets, you could tier drop your different markings.