[c-nsp] Help with configuration

Anton Kapela tk at 5ninesdata.com
Sat Dec 30 18:20:01 EST 2006


> priority command is not supported in output direction for 
> this interface
> 
> Configuration failed!

Yup! It did! ..and it will on ws-x65xx, 67xx, and 68xx cards. You need
OSM, SIP/SPA, or 20G line cards for MQC LLQ (low latency queuing, aka.
'priority' in the policy-map) to work. 

> Now neither band percent
> bandwidth percent command is not supported for this interface
[snip]

That won't work either as you have noticed.

> IP7COL01(config-if)#wrr-queue ?

Getting warmer...

> Is there a way to provide that MQC configuration but for that 7600
> switch ??

Nope. The good news is you can achieve most of the same PHB's with WRR
on 67xx line cards. It's not obvious how it works, though. 

Read the following documents to understand the qos arch of the
cat6/7600:

http://tinyurl.com/ze9xu

Page 11 has a graphic which depicts what you need to setup. In short,
you need to do the following:

A) match $whatever packets in class-map, using ACL's, precedence, etc. 

B) in the policy-map, set the mpls exp bits as you indicate

C) also set their CoS (class of service) values in each class

C) map CoS values to the appropriate WRR queue structure(s)

D) apply policy-map to egress port

E) setup WRR parameters on egress port

The example in the PDF shows matching on DSCP to set CoS, but you can
use prec. In the context of cat6 or 7600 'LAN' line cards, you can only
control egress queuing based on what CoS value a given packet is mapped
to. Ingress queuing (aka. 'scheduling) can only work on based on
port-trust state.

Examples are in the document, but the point is to do something like
this:

 class-map match-all class-1
   match ip precedence 0

 policy-map example
   class class-1
    set cos 0
    set mpls experimental 0

Also, read up on http://tinyurl.com/y939ht - covers all one needs to
know about PFC qos and what you can/cannot do. 

-Tk



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