Cisco VOIP QoS - passing on the markings

I have auto qos turned on my edge switch.  I have a trunk to the root bridge and router via a gig port on each.  How can I verify that RTP packets are getting the properly slapped with DSCP value EF and that that is being maintained as I hand off the RTP packets to my MPLS provider?  When I am looking at the netflow data for the WAN/MPLS router I am seeing the RTP traffic marked as CS0.  And I'm trying to troubleshoot how the packets are losing the EF that I believe the phone puts on their natively and the Auto QoS should slap on there if not.  


interface FastEthernet1/0/6
 switchport mode access
 switchport voice vlan 2
 srr-queue bandwidth share 10 10 60 20
 srr-queue bandwidth shape  10  0  0  0
 priority-queue out
 mls qos trust device cisco-phone
 mls qos trust cos
 auto qos voip cisco-phone
 spanning-tree portfast
 service-policy input AutoQoS-Police-CiscoPhone
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amigan_99Network EngineerAsked:
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Jody LemoineNetwork ArchitectCommented:
By default, the Catalyst switches rewrite the DSCP of outgoing packets based on the CoS.  I have never understood why they do this because DSCP is more granular than CoS. If you want to ensure that the switch preserves the DSCP of the packet, use the global "no mls qos rewrite ip dscp" command.

Tracking the DCSP coming into or leaving the switch can be done by using extended access lists that permit traffic with each DSCP marking and logging hits to the buffer.
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amigan_99Network EngineerAuthor Commented:
Excellent.  Thank you.
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