not able to configure QoS on 3750 Metro Ethernet Switches

Unanswered Question
Feb 25th, 2009


I am using 3750 24-ports ethernet switch and need to configure QoS but not succeded.

I am using c3750me-i5-mz.122-25.SEG1.bin IOS.

I am not able to configure below command-

service-policy output|input <policy name>

Please let us know for any further information required & please help me.


I have this problem too.
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jitendra.kansal Wed, 02/25/2009 - 20:56

Hi Joseph,

Thanks for your reply,but I am getting follwoing errors while implementing QoS under fast ethernet-

SW(config-if)#service-policy output QoS

Feb 17 08:46:55: cqm_check_service_policy: Assigning a policy to output side of an unsupported interface

SW(config-if)#service-policy input QoS

Bandwidthis only supported in a hierarchical policy on ES interfaces



Joseph W. Doherty Thu, 02/26/2009 - 05:32

Most small L3 switches don't support the same QoS features as the small routers. The ME3750 also supports different features based on type of port. It appears from your messages, what you're trying to do isn't supported.

jitendra.kansal Thu, 02/26/2009 - 05:44


I need to know which QOS policy is supported by 3750ME switch.

As i have already posted my requirements that we want to execute QOS on fast ethernet ports as well as Gig ports, kindly suggest will the above mentioned policy will work for the same or NOT.

I also want to know the supported policy commands on ME3750 switch.

Kindly help me out.



Joseph W. Doherty Thu, 02/26/2009 - 05:54

The reference I provided, along with the reference manual, would explain best the QoS features available on the ME3750.

My understanding, though, is the ME3750's FE ports don't support the QoS features of the (ES) gig ports.

If the device doesn't offer the features you need, beyond using a different device or doing without, sometimes newer IOS versions add features. So besides reading the QoS capabilities of your installed IOS, you might want to review release notes and/or read the QoS sections of the latest IOS for the platform. (Many features in these platforms are very dependent on the hardware, so enhancements, if any, tend to be minor.)

jitendra.kansal Thu, 02/26/2009 - 06:01

we are not clear with above statement,

does Gig Ports of 3750ME will support QoS or we need to verify IOS which support QoS.

As per our analysis, current IOS feature set is-


& QoS feature supported are with it-

-Modular QoS CLI (MQC)

-MPLS Quality of Service (QoS) Enhancements

-QoS Packet Marking

Could i deploy prev mentioned QoS Policy with current having above mentioned feature set.

OR suggest me to go which IOS?

Joseph W. Doherty Thu, 02/26/2009 - 06:38

I haven't worked with a 3750 Metro switch, but from the information in my reference, and QoS.txt you posted to Giuseppe, it appears there's a good chance the ES ports would accept your policy.


What you're trying to do, I believe, could also be accomplished on a non-ES port, much as it would be done on a "normal" 3750. However, how it's done is totally different.

Joseph W. Doherty Fri, 02/27/2009 - 04:21

If I'm reading the documentation correctly, SVI related QoS seems to be only for non-ES ports. For ES ports, it appears you would apply the policy to the interface.

Giuseppe Larosa Wed, 02/25/2009 - 10:01

Hello Jitendra,

in which configuration context are you trying to give the command ?

An SVI, a physical interface, an ES port ?

how is the configuration of the policy map it includes QoS hierarchy ?

see for your platform and IOS version

there are differences depending on the type of interface and the type of policy-map used

I think you need to give

conf t

mls qos

before being able to use QoS commands as in other switch platforms

Hope to help


jitendra.kansal Wed, 02/25/2009 - 22:15

Hi Giuseppe,

Please find attached sample configuration, please help me to digout where i am wrong.

after that while i am applying it into any interface i got error messages as i posted earlier.




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