QoS on Ethernet Subinterface not working

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Aug 19th, 2008
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We recently moved from a Serial to an Ethernet link for one of our WAN links.

We created a parent service-policy, included the shape average command and the old service policy as a child. Then we applied the new parent service-policy on the subinterface.

It seems that after applying the QoS service-policy to the subinterface on the router it is not applying the policy since the show policy-map interface output counters remain at zero.

Below is the relevant configuration, any ideas?

class-map match-any Priority

match ip precedence 1

class-map match-any Normal

match ip precedence 0

class-map match-any Voice

match ip precedence 5

policy-map QoS

class Priority

priority 256

class Voice

priority 576

policy-map QoS-Parent

class class-default

shape average 2097152

service-policy QoS

int fa0/1.667

service-policy output QoS-Parent


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Giuseppe Larosa Tue, 08/19/2008 - 12:45
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Hello Joe,

support of modular QoS on subif is platform dependent and in some cases IOS vers. dependent.

What router are you using ?

Try to think of a different configuration using extended ACLs to define classes to use a policy-map applied at the physical interface.

Otherwise you will need a dedicated interface.

Hope to help


c2jkeegan Tue, 08/19/2008 - 12:49
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It's a 2811 running 12.4 Advanced Enterprise (c2800nm-adventerprisek9-mz.124-15.T3.bin)

Do you know where I can find out if this router supports module QoS on subinf or where I can find a list of routers that can support it?


Joseph W. Doherty Tue, 08/19/2008 - 14:30
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Don't know if this is the cause of your problem, but I have documented with Cisco that certain configurations of QoS within the 12.4(15)T train don't properly update counters. (The QoS, though, did seem to function correctly.) You might try upgrading to 12.4(15)T7 or 12.4(20)T. (Also don't know if problem fixed in either.)

Steve Lyons Wed, 08/20/2008 - 16:31
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Open a case with TAC 1800-553-2447. TAC will be able to provide you configuration assistance and feature support.

Steve Lyons - Cisco


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