Priority on an access port¿?

[ciscolover]

Hi all,

I have observed than I can add priority 0-6 to an access port.

I thought this priority was valid only to tagged ports/trunk ports because the CoS priority could be applyed only to tagged frames.

Please, how it works this priority¿

Thanks ¡¡¡

[acampbell]

Hi,

The cos priority will be added to all
frames entering the port/interface.

Tagged frames will indeed already have
a COS value and depending whether you
use the overide part of the command will
determine whether you ammend the users value of
COS or not.

Remember that untagged frames may need to
be given priority in your network for some
reason. You can achieve this by setting
a COS on the port/interface.

A 2960 interface may be something like this

see this link:-
http://www.cisco.com/en/US/docs/switches/lan/catalyst2960/software/release/12.2_55_se/configuration/guide/swqos.html#wp1032169

!
interface fast 0/4
switchport access vlan 4
switchport voice vlan 400
mls qos cos 4 overide
!

This will in affect rewrite the tagged vlan 400
and the untagged vlan 4 frames all to COS 4

Hope this helps

Regards,
Alex.
Please rate useful posts.

[ciscolover]

Thanks for your answer.

I tought than only the tagged frames had priority CoS.