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QoS Policy not activating

Brian Green
Beginner
Beginner

I am having a problem getting a QoS policy to activate.

I have a 2921 ISR router with several VRFs defined on it, and several DMVPNs.  What I'm trying to do is enact QoS using a simple policy - I would think the place to apply it would be the router egress interface since that interface doesn't use VRFs or DMVPNs.  When I view the policy using "show policy-map interface" the number of packets in the class stay at 0.

 

I have an Extended Access List:

 

ip access-list extended name Test1_acl

 permit ip X.X.0.0 0.0.255.255 X.X.0.0 0.0.255.255

 

where X.X.0.0 is the subnet of nodes within one of the VRFs going to a destination over a DMVPN Tunnel.

 

And that connects to a Class Map:

 

class-map Test1_cm

 match access-group Test1_acl

 

which connects to a Policy Map:

 

policy-map Test1_pm

 class Test1_cm

  bandwidth percent 25

  set dscp af31

 

I've applied this to an interface:

 

interface GigabitEthernet0/2

 ip address Y.Y.224.1 255.255.255.0

 service-policy output Test1_pm

 

When I issue a ping from a workstation on the X.X.0.0 subnet, the packet (as I underdstand it) goes to the 2921 router, enters the DMVPN, then gets sent out on g0/2 - but the Source and Destination IPs are left unchanged.

 

What I am seeing when running an infinite png is all the packets go into the default class and none into Test1_cm.

 

Any ideas how I can make this work?

 

Thanks,

 

Brian

4 Replies 4

Joseph W. Doherty
Hall of Fame Master Hall of Fame Master
Hall of Fame Master

You policy is on the physical egress interface?  If so, what IPs are you matching against, tunnel end-points, or pre-DMVPN source/destination IPs?

I managed to find a working solution - I created a simple policy map to apply the DSCP markings to the packet on its way IN to the router - so the QoS policy on the output interface can use that as the differentiator.  Not elegant, but (I think) it works.

 

Thanks!

 

Brian

Yes, that could be a solution because generally original packet's ToS byte is copied to the encapsulated header's ToS byte.

Otherwise, without using qos pre-classify (don't recall whether it works with DMVPN), egress interface QoS policies "see" the encapsulated header.

I was looking at some captured packets - the IPv4 Header had the DSCP field set properly once I changed it on the ingress interface.  So it does propogate it through.  I do have the "qos pre-classify" command set on all my VPN tunnels.

 

Brian

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