Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

QOS on Port-channel

Can someone please confirm, I'm configuring a Cisco 3750 running 12.2(25)SEE2 and I can not use the "mls qos trust cos" command on the port-channels, I can on the physical interfaces that make up the port-channel eg Gi 1/0/1, I've been looking round the Cisco web site and think that you only need to put the mls commands on the physical interface but would like a second opinion.


Re: QOS on Port-channel

Whenever you use "mls qos trust device cisco-phone" command, you can think of it as enabling trust settings to take effect as long as the cisco phone is detected on that port. You still need to enter the command: "mls qos trust cos" if you want cos to be trusted. This command is used to form a trust boundary where a user cannot simply plug in their PC directly to the port and get priority queueing.

Super Bronze

Re: QOS on Port-channel


That's correct - you'll apply QoS (priority-queue, mls qos trust commands) on the physical port..

Then apply other things (like switchport mode trunk etc) on the port-channel... which then cascade down to the physical ports. All very confusing... it would be nicer to see some consistency with these configurations.

You do have it right as it is though.



Please rate helpful posts...

Aaron Please remember to rate helpful posts to identify useful responses, and mark 'Answered' if appropriate!
New Member

Re: QOS on Port-channel

aaron, thanks for the help.