Here is the topology that I have:
Phone => (access port) L2 Switch (trunk) => Router
My goal here is to add an EF tag to the packets coming from my phones. Basically, if a packet comes in being in Vlan 30, I want to modify the L3 header and add DSCP EF.
Would that be possible to do that on my L2 switch, or can I only modify the CoS tag ? My switch is a C3750