I am studying for the BCMSN and have a question about VoIP and trunking.
I see that when you have an Access port you should add lines:
mls qos trust device cisco-phone
mls qos trust cos
auto qos voip cisco-phone
Do I need to add anything of these to the trunk port?
Should I add anything else to the trunk?
Also, if there was a point-to-point with routers, would the trunks need anything else special to allow QoS to function properly?
auto qos voip cisco-phone command enables the other two commands :
mls qos trust device cisco-phone---- the interface is trusted only when cisco ip phone is dectected via cdp.
mls qos trust cos---once deteced CoS values is trusted.
Ideally yes we trust the trunk ports for the incoming traffic. If you your traffic is local to the switch and does not cross trunk ports you dont need any configuration on the trunk ports.
"auto qos voip trust" is used on trunk links.
Hope that helps.