in gneral, what are the conditions that make a switch generate a topology change notification (TCN) and not just sending an inferior bpdu in case of a link failure or a topology change.

What is the default behaviour of a cisco ip phone regardless of trunking. Does it use dot1q encapsulation and sets Cos to 5.In case we use the command (config-if)#switchport voice vlan untagged on the switch, what effect does this command has on the...