Voip Phones and VLANs

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Nov 30th, 2007
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I have a 3524 setup for VLANs. One port is configured for a client VLAN which the cable plugs into a PoE module for a VoIP phone on the other end. The client PC is daisy chained of off the VoIP phone.

What configuration do I add to the switchport to allow the VoIP phone to connect to the network?

it is currently:

switchport mode access

switchport access Vlan 'client vlan #'

THe Voip phones have their own VLAN on the switch.

Thanks in advance.


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Edison Ortiz Fri, 11/30/2007 - 10:40
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Two options (and it depends on the VoIP manufacturer).

The Cisco VoIP procedure:

switchport mode access

switchport access vlan [client vlan]

switchport voice vlan [VoIP vlan]


switchport mode trunk

switchport trunk encapsulation dot1q

switchport trunk native vlan [client vlan]

Based on previous conversation with another forum member, it seems Avaya and other VoIP manufacturers are using option 1.

Try it option 1 first, if it doesn't work, try option 2. Keep in mind, you need to configure your DHCP and TFTP accordingly. Read the VoIP deployment guideline from the phone manufacturer.

Ericunicast Fri, 11/30/2007 - 11:43
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Ok, i will try that.

If the phone has a static IP, will DHCP need to be configured.

Currently, the phones are setup on a flat net, static IPs that connect back to the Call Processor.

Edison Ortiz Fri, 11/30/2007 - 14:52
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The DHCP supplies an option string to the phone that contain useful information such as its native vlan, dscp/cos values (qos), among other things.

You need to investigate with the phone manufacturer.

a.cruea1980 Fri, 11/30/2007 - 12:41
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I was under the impression that with Cisco gear, all you have to do is:

switchport access vlan (vlan)

switchport voice vlan (vlan)

This is how we have it set up when I've seen Cisco VoIP phones in use.

[edit]Although specifying the mode seems to be the Cisco recommendation. . .weird.


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