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QOS and the campus switching design model

Hi all,after reading the cisco srnd on the campus lan design model, it says that QOS policies should be applied at the distribution layer, my question is, what kind of policies? as I thought that most qos is done at the edge, with regards to marking etc. Would we just trust the DSCP mark at the distrubution layer? and would we need to trust this also between the distrubution and core layers ?

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Re: QOS and the campus switching design model

Errrm Carl,

you say you have read the SRND for QoS - specifically the Campus QoS Design?

You ask "it says that QOS policies should be applied at the distribution layer,"

On page 1 of the Campus QoS Design under "QoS Design Overview" just above figure 2-2 a thrid of the way down the page - there is a big chunk of text, I will post for you:-

"So where is QoS required in campus?

Access switches require the following QoS policies:

•Appropriate (endpoint-dependant) trust policies, and/or classification and marking policies

•Policing and markdown policies

•Queuing policies.

Distribution and core switches require the following QoS policies:

•DSCP trust policies

•Queuing policies

•Optional per-user microflow policing policies (only on supported platforms)"

Did you miss this when you read the document?

Community Member

Re: QOS and the campus switching design model

Hi there

So if my access layer switches, do a 802.1p to dscp marking, then all I have to do at the distribution and core layer is to trust this?

what about queuing? why would i need to change this at the dist/core layer?

Re: QOS and the campus switching design model

Yes.

Because - if you have followed the guide and are using the switches recommended on the Dist/Core - then you will know they do not support, Policing, Dropping, Shaping. They queue, and buffer with thresholds using weighted tail drop.

Community Member

Re: QOS and the campus switching design model

can you expand on this a little at all ?

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