Cisco Support Community
Community Member

Configuring Access and Trunk vlans


can we configure both access and trunk vlan on same interface ?

In the below example, we have a dedicated Voice vlan 600 and a data Vlan 100 for IPT. Can this be possible making access vlan for one and trunk for another ?

interface FastEthernet0/3

description -- To Voice Gateway

switchport access vlan 600

switchport trunk encapsulation dot1q

switchport trunk native vlan 100

switchport mode access

switchport voice vlan 600

speed 100

duplex full

priority-queue out

mls qos cos 5

mls qos cos override

no mdix auto

power inline never

spanning-tree portfast


Re: Configuring Access and Trunk vlans

Hi Arshad,

This will work but I see you have configured vlan 600 as voice vlan also and access vlan also which I do not think is required and even if you do not configure trunk and just configure voice vlan 600 and access vlan 100 for data it will work prefectly.

I have seen some problems when you cofnigure a specific trunks but it works perfectly if you just configure voice vlan and access vlan for data and do not configure a specific trunk. When voice vlan command is issues it internally forms a trunk.



Re: Configuring Access and Trunk vlans


As Ankur has pointed out that u r having access vlan and voice vlan same this is not going to work.u need to have seprate vlans for voice and data.i see that u have configured native vlan 100 what i suggest u is dnot configure any access vlan what is going to happen is u r pc will be in u r native vlan i.e 100 and as u have configured voice vlan 600 it will work.and if u have configured this as a trunk port make sure u clear all the vlans leaving only u r data and voice vlan i.e u just allow vlan 100 and 600 on this port.



Re: Configuring Access and Trunk vlans

Hi Arshad,

Which switch is this and what's the model number. The above config will not work on a switch port.

If you have 3500xl's then you have to set the ports as trunk ports for carrying the voice and data vlans specifically.

If your switch is 3550 or above that you dont have to set that port as a trunk port. Just define the voice and data vlan and both the vlans traffic will be carried over an automatic special dot1q trunk between IP phone and switchport. Some people set the ports as trunk on these switches and have faced a lot of problem and as per the experience goes above step is the recommended one.

Please write if need more clarifications.

HTH, Please rate if it does.

-amit singh

CreatePlease to create content