qos trust cos or qos trust dscp?

[mcombs]

My core switches are a pair Cisco catalyst 4006s with a sup 4 module. The questions are:

1. Should I use qos trust cos or qos trust dscp when setting up qos on a per port basis?

2. Which is preferred?

3. I have a cos to dscp mapping so does it really matter?

Any help is greatly appreciated. I just want to make sure that I'm honoring all tags.

Mark

[bwilmoth]

If you have ip phones connected to the switch, you can enter qos trust cos on the switch and in the router which is connected to the switch enter the command to trust the DSCP since the switch will pass the dscp information to teh router.

http://www.cisco.com/en/US/docs/ios/qos/command/reference/qos_m2.html#wp1015945

[furionsky333]

why ? I can't input command "mls qos trust dscp", instead of only input "qos trust dscp".

what difference between this two command?

thanks a lot

[islam.kamal]

Hi

They are the same commands , the only difeerence the IOS supported commands. You will find also to trust cos instead of  mls qos trus cos . You also have to use auto qos default instead of auto qos voip trust.

Thank you

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