Vlan---Trunk & Access

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May 19th, 2009
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Is it possible to configure both trunk and access/voice vlan in a single switch port.i have seen a similar configuration in a live environment.


Int Fa5/12

Switchport access vlan 5

switchport voice vlan 10

switchport trunk native vlan 5

switchport trunk allowed vlan 5,10


can anyone explain how it is working?.....

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smothuku Wed, 05/20/2009 - 00:47
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smothuku Wed, 05/20/2009 - 00:49
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Hi ,

Example :

switchport trunk encapsulation dot1q

switchport trunk native vlan 16

switchport mode trunk

switchport voice vlan 201


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 ,


bava_ccna Thu, 05/21/2009 - 17:20
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Thanx for the reply...

can i connect the port to a pc with the same configuration...Will it harm anything?..


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