Tuesday, February 6, 2018

Cisco Ingress policing best practice for flow-fairness?

I'm looking into turning on Flow -Fairness based WFQ on the egress side to "automagically" deprioritize large file transfers in favor of smaller traffic (RTP, small www, etc). without having to do any specific marking or classification. As I understand it, this is closest thing to fq_codel/ sqm in the Cisco World.

Of course as I understand it, unlike fq_codel/IFB which creates a simulated inbound queue, WFQ is egress only which means ingress will be a regular FIFO queue with no attempt to use flow-fairness to determine what traffic gets dropped first.

An inbound policer is, as I've been told a best- effort, mostly TCP drop strategy. If I set a policer to 85mbit, is there anything I can do on Cisco firewalls to select what kinds of traffic will be dropped on purpose (versus traffic that might be dropped by accident, when the policer is overwhelemed by un-cooperative traffic).

Explained another way: Egress will use "Flow-based WFQ" with a 85mbit limit (no Classes for now). I assume there's no WFQ on ingress, even in a best effort capacity. Can I specify a class of traffic on ingress that will never be dropped on purpose? Can I do it by packet size? (e.g. never drop packets of size less than x)

Line speed is 100/100 Fiber.

Bonus: If no one says "there is no QoS on the internet", or "you cannot control packets once they have reached your interface" I give everyone on r/networking 1BTC.



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