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QoS on a 3750

I'm in the process of implementing QoS on our network...I've already been using it on our Edge routers and that's working pretty well. However I'm having some issues doing it on the LAN, specifically on our 3750's.

To start I'm just trying to mark management traffic (ssh and telnet ports) with CS2 coming from my machine. The problem is that sho policy map int gi 3/0/43 doesn't increment the policy-map counters which I understand is a problem with all catalyst switches. However our 6500 I'm not seeing CS2 in netflow, and when I try to deny all traffic with CS2 just to test on the uplink on the 3750 it's blocking the traffic and the ACL counters for that line are not incrementing (deny ip any any dscp cs2). The uplinks on the 6500's have qos enabled and have mls qos trust on t he uplinks to the 3750, which is a Layer 3 Etherchannel port. Any ideas why this wouldn't work? Here is the config:

mls qos

Extended IP access list Management

10 permit tcp host any eq 22

20 permit tcp host any eq telnet

Class Map match-all management

Match access-group name Management

Policy Map standard-qos

Class management

set ip dscp cs2

police 1000000 64000 exceed-action policed-dscp-transmit

int gi 3/0/43

service-policy input standard-qos

Community Member

Re: QoS on a 3750

Use 'sh mls qos interface [interface] statistics' on the 3750's uplinks to the 6500's, physical ports not the etherchannel. If DSCP is getting changed as per your policy map then you will see the outgoing counters rising for CS2.

If they are rising then the 3750 is doing what it's told.

Community Member

Re: QoS on a 3750

Hi In your configuration

You configured ..CS-2 -> DSCP 16

So, Try another method

1) try other value value AF31- DSCP26

2) check the traffic marking via the monitor the port with

packet analyzer ( ex sniffer, etherreal )

3) check the status with the show command for the QoS


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