can voice vlans still work if phone plugs into other switch first

Unanswered Question
Jun 2nd, 2009

Hi all, If I plug a phone into a unmanaged switch, this then plugs into a normal cisco switch with voicevlan and normal vlan, will it still work?

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a.cruea1980 Tue, 06/02/2009 - 07:16

I believe your Cisco switch will see all data coming into it as just data. So you'll have to set the data VLAN and voice VLAN the same to get the phone to work.

If memory serves me correctly, when you plug a Cisco phone into a Cisco switch, it creates a special trunk link that sends a data VLAN and voice VLAN over it. If you put a switch in between the Cisco devices, it cannot set up this trunk link and send the proper info (to my knowledge).

It's just as if you plug one Cisco phone into another; the first phone would be set up on the voice VLAN, but the second phone has to be set up on the data VLAN because the second phone cannot set up the necessary link that it needs to bring up.


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