[c-nsp] Question about monitoring DSCP marking

[Paolo Lucente]

A policy-map simply meant to roll counters or (better) NetFlow come to mind.

Cheers,
Paolo

On Sun, May 16, 2010 at 08:50:44AM -0600, Nick Voth wrote:
> Hello folks,
> 
> Here's the situation. I have a number of customers who are using XO
> Communications for T1 DIA access. These customers are also VoIP customers of
> ours and their VoIP (SIP) traffic all aggregates through a session border
> controller in our network. All inbound and outbound VoIP goes through these
> session border controllers.
> 
> Their SIP traffic traverses the XO network and to a peering point with us.
> We have set up QoS rules on the customer's CPE equipment, (Cisco 1800 series
> routers), so that their outbound VoIP traffic is prioritized in to a
> priority queue. That works fine.
> 
> XO has just released a product that will allow for priority queuing on the
> network switch that is closest to the customer. It marks the traffic with
> DSCP value of 46, (ef), and puts this designated traffic in a priority queue
> pointing towards the end user. In theory, this should help prioritize the
> VoIP traffic from both ends of the customer's T1.
> 
> Nice in concept, but here's the question. Without having direct packet
> capture capabilities in a customer's network, is there any way in the Cisco
> IOS to see if the incoming VoIP packets really do have the express
> forwarding bit set?
> 
> On the outbound side from the customer that's easy, but I don't know how to
> verify that XO is really doing what they say without actually seeing the
> packets in something like Wireshark.
> 
> Thanks for any advice.
> 
> -Nick Voth