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QoS on ASR sub-interface



I've searched the forums but haven't found anything that explains the problem that I'm having.

Goal: I'm trying to prioritize traffic to and from specific IPs (listed in an ACL) between offices by setting the dscp value to AF41

Problem: On the branch office (3800 series router) the MPLS connection comes in on physical interface.  I can apply a service policy to that physical interface outbound and it works correctly (as seen by sh policy-map int < >).   The problem exists on the ASR 1002 side.  The MPLS connection is on a sub-interface.  I tried applying an outbound service-policy but after generating traffic that class-map is never hit.

I then read somewhere that because it is a sub-interface that you would have to shape it first and then use a child policy to set the dscp value.  I tried that but that doesn't work either (no hits).  It seems to me with that with that configuration, you would have to reach the limit of the shape first before it started marking traffic.  I don't want to shape the traffic, only mark certain traffic with a higher priority.

Tried this first:

class-map match-all Priority-outbound

  match access-group 100

policy-map Outbound

  class Priority-outbound

     set dscp af41

int gi0/0/1.1

service-policy output Outbound

Then I tried this:

class-map match-all Priority-outbound

  match access-group 100

policy-map child

class Priority-outbound

  set dscp AF41

policy-map Outbound

class class-default

  shape average 60000000

  service-policy child

int gi0/0/1.1

service-policy output Outbound

4 Replies 4

Marwan ALshawi

Can try using a named acl rather than numbered I has issue with matching ack in asr before for ssh

Also try to apply it in the physical nit dub interface for testing and c if it's work

Good luck

Sent from Cisco Technical Support iPhone App

Thanks for the reply.

I tried using a named ACL and tried applying the policy to the physical and then the sub-interface.  Unfortunately with the same result.  I'll contact TAC and see what they say.

After talking with TAC they explained the following:


ASR router is a hardware switching based platform compared to other routers like 7200,7300 etc..which are software switching based platforms. All the packets will be switched at the line rate by QFP in ASR. The statistics reported for ACLs called under class-map report the packets which are handled by software. Since the ASR is hardware switched platform, these counters will not report any value.

If you are running the new IOS XE 3.3S you can use the following command to see the marking on the QoS policies:

platform qos marker-statistics

According to the documentation you'll have to remove any policies you have, enable the marker-statistics feature and then re-apply your policies.

Also the newer versions of the IOS support QoS over multi-point DMVPN which would be the direction we would take.

Hope that helps somebody.

Thanks for the update 5+

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