IP Phone and Call Manager on different networks: possible?

Unanswered Question
Sep 23rd, 2010
User Badges:

Is it possible to have an IP Phone (a 7940 in this case) on a different network than the call manager? We've

sucessfully deployed 7936 Conference Stations to a remote location, but those can specify the TFTP server.

The IP phones however, look for a TFTP server to respond. Is there a way to configure the network to facilitate

this? (I'm not a network guy so I'm unclear on this!)

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (2 ratings)
Matthew Kaufman Thu, 09/23/2010 - 17:56
User Badges:
  • Cisco Employee,

There are a couple options here... you could configure the DHCP scope with the TFTP server of the CUCM server and if the network is routable, it will be able to download its configuration and register with the server.  Also, depending on the number of phones you could manually configure the TFTP server address on the phones so that they can download their configurations and register with CUCM.

Let me know if you have questions.


jaschulz Thu, 09/23/2010 - 20:59
User Badges:
  • Bronze, 100 points or more

Great suggestions from Matthew!!! Keep in mind also you can use the local gateway to configure a dhcp pool for the phones too. And manually configuring the tftp server on the phones.

Chris Tolley Wed, 09/29/2010 - 12:23
User Badges:

Thanks for the tip on setting TFTP on the phone. Didnt know the could be done (and that settings could be modified).

We also found out the Dell switches may not support CDP.

Ashley Georgeson Wed, 09/29/2010 - 14:51
User Badges:

Hi Chris,

It's not a problem that your switches do not support cdp.  Cisco phones use this to determine the voice vlan and other bits and pieces.

You will need to manually configure your switch ports, typical configuration is to trunk two vlans, one for data and one for voice.

If you do this, remember that you will need a dhcp pool for each vlan, each with the correct options, e.g. option 150 for tftp server.

Kind regards, Ash.


This Discussion