I am a little confused about the mls qos trust command as it applies to phones, servers, routers and inter-switch links. No matter what, I am running the auto qos voip trust (or device cisco-phone) for all the ports on my network. I was told once that when a port connects to a server (Call Manager, TFTP, etc) or a Voice Gateway I should turst DSCP, but then I have read that unless it is a trunk, this is not correct.
So, for the items listed above (and below)
should I be trust CoS or DSCP with the mls qos trust command?
Just a note on the switches...trusting CoS on switch uplinks works fine if you're just doing Layer 2 switches, but with Layer 3 switches you'll want to trust DSCP. It's my understanding (and observation), then when the packet goes through an SVI the layer 2 CoS gets reset but the DSCP is preserved.