[c-nsp] 3560 QoS/shaping

[Yan Filyurin]

Not that I am mentioning anything that hasn't been discovered, but here are two great articles about it:


http://blog.internetworkexpert.com/2008/02/23/catalyst-qos-3550-explained/#more-81

http://blog.internetworkexpert.com/tag/3550/

Neither one of them answers your question, but I think with 3560 (and 3750 non uplink ports have the same capability) you might not police, but you can easily direct any packet marking into any of the four queues and through shaping you can control it. In other words, you get very similar capabilities to class based queuing.  In other words, could you configure one shaped queue and then put all the packets there based on COS or DSCP and then even define thresholds for different traffic. And you can also allocate buffers for various queues. 

Another alternative to ingress policing is storm control.

Yan



________________________________
From: Brad Henshaw <brad.henshaw at qcn.com.au>
To: Jon Lewis <jlewis at lewis.org>; cisco-nsp at puck.nether.net
Sent: Wednesday, January 14, 2009 10:12:31 PM
Subject: Re: [c-nsp] 3560 QoS/shaping

Jon Lewis wrote: 

> I'm configuring my first 3560s...
> you can't police the output of a port
> you can't even define an output service-policy for a port.

This is correct as far as I'm aware.

> It appears the 3560-way to do this is to use srr-queue bandwidth
> shape on the interface, but the syntax for this command isn't
> nearly as flexible...
> Is this possible on the 3560?

You can try the 'srr-queue bandwidth limit' to rate-limit traffic on
egress but this is only done at the port level for ALL traffic and has
its own limitations as it's percentage-based. The only option other than
what you've suggested and the srr-queue bandwidth limit is to apply
ingress policers on all of the relevant ports. You /might/ be able to
get away with using an aggregate policer in this situation but I have no
idea whether this would be supported at ingress on the 3560.

You'd need a 3750ME for anything much more advanced -- and even then,
this functionality is limited to two of the gig ports. I think the
3400ME's support egress policies but they have their own limits and
retardations in this respect.

Regards,
Brad
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