iftikharsyed_2 Thu, 02/12/2009 - 02:19


If you are talking about DHCP on Cisco Switches its possible, you can define voice VLAN for each port.


Iftikhar Ahmed

jbillingsley@ne... Fri, 02/13/2009 - 12:09

You'll have to configure the Switch Ports in the Voice VLAN. Are your phones connected to a Cisco switch?

I'm not familiar with setting a VLAN via DHCP. Usually you'll want option 150 for TFTP and your other basic settings

Chris Deren Sat, 02/14/2009 - 09:18

Correct, you do not set VLAN on DHCP, you do it the other way around, you define DHCP scope for VLAN.

So, in IPT environment you define data vlan and voice vlans on the switchports, then based on the vlan the device connected to the switchport determines which one to use, in IP phone case it picks up voice vlan via CDP protocol, and then of there is a dhcp scope defined for that VLAN on your L3 device, either router or L3 switch it obtains the IP address from the dhcp provider. For the phones to get the IP address of the TFTP server you need to include option 150 pointing to the CM TFTP server on the DHCP scope.




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