Hi,
My understanding is that they are different. You use the pvlanid when you are going to configure a switch port where you need to specify the Vlan ID, for example:
switchport access vlan "vlanid" or
spanning-tree vlan "vlanid"
Tagging is a mechanism used by the trunking protocol to identify Vlans. It add a tag to every encapsulated frame that contains the Vlan number.
Let me know if it helps.
