[nsp] Queuing with rate-limiting

[Tim Franklin]

Previously, cisco-nsp-bounces at puck.nether.net <> wrote:

> Anyone got any thoughts on the best solution to achieve the
> following.. 
> 
> 
> I need to do some queuing to give priority to some traffic over
> others, I can do
> this with various queuing strategies.. (the traffic can be
> identified with acls
> to ascertain priority)
> 
> The link this is on altho 100Mb has slower links between my
> router and the
> destination so for the queuing to work properly I also need to
> rate-limit the
> traffic on a 100Mb port down to that of the slowest link.

MQC with nested policies would seem to be what you want.

You can apply a shaping policy to the interface, then nest your queuing policy within the shaper - you'll get the traffic shaped to your desired rate, and within that amount of bandwidth, you'll get traffic prioritised as you define.

Something like:

policy-map shape
 class class-default
  shape average 2000000
  service-policy queue

policy-map queue
 class class-1
   bandwidth percent 30
 class class-2
   bandwidth percent 20
 class class-3
   bandwidth percent 10

interface fastethernet 0/0
 service-policy output shape

Would shape the traffic to 2M, with 30% reserved for class-1, 20% for class-2, 10% for class-3 and rest available between these classes and the default class.  Any unused bandwidth in a class spills over to the other classes. (It's actually scheduler weightings rather than strict bandwidth reservation per se, but the net effect is the same.)

You'll also need class-maps to define the various classes, typically by ACL.

Regards,
Tim.

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