[c-nsp] Subrate speed on GigE requiring QoS / Policer configuration

[Keegan Holley]

Do you really need he qos configuration to do anything when there's no congestion?  In other words if you're only using 5m or so and everything is ok what would you want the qos to do there?  If you make af and ef priority queues you can ensure that traffic is given priority and also that it does not starve other flows.  The one caveat is that when here's no congestion they still will use more than 2m each.  I'm no qos expert but i know can assign drop probability so that certain traffic is dropped at a higher rate, but even that is only done during times of congestion.  I'm not sure if you need you policy when there's no congestion.  Unless I'm missing something.

Sent from my iPhone

On Oct 5, 2010, at 10:49 PM, Chris Evans <chrisccnpspam2 at gmail.com> wrote:

> I'm struggling to come up with a solution for my requirement.. Essentially
> we are building a lab using GRE to link two sites over our enterprise
> network. As this is a lab we want to limit the bandwidth that comes out of
> the LAB to 15megabits, but using GigE for the physical connection on an
> asr1k. Essentially my first thought was implement a policer on the egress
> interface limiting the maximum aggregate traffic to 15Mb, then qos scheduler
> on the tunnel interface or egress GigE. I need to prioritize certain traffic
> leaving the lab so I also want to use a scheduler to make sure that the
> voice traffic has priority and has a 2Mb of traffic for example.
> 
> I want to limit my EF traffic to 2Mb, AF to 2Mb, NC to 500Kb and best effort
> to 10.5Mb under signs of congestion within that 15Mb CIR. My challenge is
> that QoS only kicks in under signs of congestion, how would you allow the
> dynamic bandwidth allocation when the egress interface is really a GigE?
> 
> Anyone have a good configuration that would fit my needs?
> 
> Thanks
> 
> Chris
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