WRED with CBWFQ

[Ahmed Dockrat]

Hi

If I have the following policy applied on an output WAN e1 interface would the router know that wred should only drop random drop when the actual e1 is congested, so for example if AF1x is using 784k and all other classes are free, will the router allow it to burst or will it random drop once it starts bursting over 512 due to class bandwidth.

Interface Serial x/x:0

bandwidth 2048

  Policy Map OUTPUT-WAN

    Class All-AF2x

      bandwidth 1024

      random-detect dscp-based

    Class All-AF2x

      bandwidth 512

      random-detect dscp-based

    Class All-other

      bandwidth 512

      random-detect dscp-based

thanks

[Joseph W. Doherty · Accepted solution]

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Posting

Your class based WREDs will only "activate" if packets queue within that class.

The class bandwidth sets a minimum guarantee, i.e. they, alone, don't preclude additional bandwidth being used.

If AF1x was using 784k, and no other classes were active, then there would be no congestion and no WRED activation.