Hi ,
Example :
switchport trunk encapsulation dot1q
switchport trunk native vlan 16
switchport mode trunk
switchport voice vlan 201
and
switchport voice vlan 201
switchport mode access
switchport access vlan 16
First and second configurations are not same.
Second configuration port is defined as access port that is a member of VLAN 16. If you have other ports that are in this VLAN they all are essentially in the same broadcast domain - they can communicate with each other via layer 2. You would most likely be connecting a computer to this type of port.
In the first configuration the port is configured to be a trunk port with dot1q encapsulation. This port would be connected to another switch and frames would be tagged on egress. An example would be if switch 1 has ports in let's say VLAN 10 and 20 and switch 2 has ports in VLAN 10 and 20 you would trunk these VLANS over that port. The switch will tag the frame on egress so the switch on the other end of the trunk knows which VLAN the frame came from so the frame can be sent to the appropiate port(s) of the particular VLAN. the "switchport trunk native vlan" command tells the switch to send frames from that VLAN untagged.
Cheers ,
Satish
