As you all know, it's possible to override 802.1p/CoS field coming from PC attached to Catalyst switch.
This is accomplished in 2 (two) ways:
- either by '(config-if)# mls qos trust extend cos <value>'
- or via '(config-if)# switchport priority extend cos <value>'
But what about to make Cisco IP Phone to trust PC's DSCP marking ? Is this possible ?
Can you also explain, why there 2 (two) flavors of CLI to allow switch to trust to PC's 802.1p marking ?
the PC basically send untagged frames to the switch, these will normally be send as CoS=0.
the following link has some scenarios for you
I think you will find example 6 usefull
I believe there are two versions of the command for the 2 types of switches: pure layer 2 switches, and multi-layer switches.
2900 series being a pure layer 2 switch, 4500/6500 being a multi-layer switch.