QOS between routed interfaces

Unanswered Question
Oct 11th, 2007
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I am setting up QOS out to my MPLS network but do not seem to be passing dscp values between my 4500 and 3800 router. I have the interfaces setup as follows. When I run a sh policy-map int on my wan interface it does not show the voice traffice going through the voice service que.


interface GigabitEthernet4/46

no switchport

ip address x.x.x.x x.x.x.x

speed 1000

duplex full

qos trust dscp


qos dbl

qos map dscp 24 25 26 27 28 29 30 31 to tx-queue 4

qos map dscp 32 33 34 35 36 37 38 39 to tx-queue 4

qos map cos 3 to dscp 26

qos map cos 5 to dscp 46



policy-map autoqos-voip-policy

class class-default



class-map match-all L3-to-L2_VoIP-RTP

match ip dscp ef

class-map match-all L3-to-L2_VOIP-Cntrl

match ip dscp af31

match ip dscp cs3


policy-map Voice_wan

class L3-to-L2_VoIP-RTP

priority 450

class L3-to-L2_VOIP-Cntrl

bandwidth 128

class class-default


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lgijssel Thu, 10/11/2007 - 07:57
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First of all, a few assumptions that I cannot confirm from the post:

1: The 3800 router connects to your MPLS WAN?

2: The policy map as shown has been applied outbound on the 3800.

You could have an issue with trust on your LAN. In a cisco network you will need to trust QoS traffic on incoming interfaces and also on the trunks within the LAN. If this has been configured incorrectly, there will be no marked packets on the LAN. That implies that you will not see any on the WAN link either.


mls qos trust device cisco-phone on interfaces

mls qos trust cos on trunks

Also, make sure you have a voice vlan configured which has not the same vlanID as the native vlan.




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