CatOS set qos wred

Unanswered Question
May 30th, 2009

Hi all,

in a queue like this:

set qos wred 1p2q2t tx queue 1 0:80 0:100

how can i calculate the MPD?

for queue 1 min th is 0 and max is 80 but what's % of drop probability discard?

the same in a queue like this is IOS:

wrr-queue random-detect max-threshold 1 80 100 100 100 100 100 100 100

so i know that max-threshold is 80% of buffer queue and i know default min-thresold but what's MPD?how can i calculate % of dropping beetwen 40% and 80% or (for CatOS examples from 0% to 80%)?

tnx a have nice day


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Overall Rating: 3 (1 ratings)
Giuseppe Larosa Mon, 06/01/2009 - 09:26

Hello Danilo,

I've checked catos 8.7 documentation for C6500 and MPD is not mentioned.

I think you cannot configure it and this should mean it is fixed to 1 so that drop probability grows from 0 to 1 going from low threshold (that defaults to 0) to 1 at high threshold.

This happens for example also for some linecards of GSR that doesn't allow to configure MPD (if I remember correctly in engine2 linecards)

Hope to help


danilodicesare Mon, 06/01/2009 - 11:43

Hi Giuseppe,

tnx for answering.

seems quite silly not having a way to configure that parameter.

I know that, if not explicit, default should be 1 but could be useful having some stuff like this documented :).

tnx again



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