Cisco Call Manage as a DHCP Server- IP Phones are not registered.

Unanswered Question


I have two site , site 1 and site 2. both the sites are interconnected via MPLS .both the sites are using the same IP Address range... 192.168.1.x and I have only one Call Manager for both the sites (which is a DHCP Server for both sites). IP Phones are facing conflicting problem via IP assingment. Please find the attached file for reference.

Please suggest the best way out to solve this issue.



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Overall Rating: 5 (1 ratings)
Tommer Catlin Wed, 11/04/2009 - 14:09

To be honest, you really need to re-do your design completely.

Create a NEW subnet for the remote site.

Create a DHCP scope on the the local voice router or Cisco IOS, include the Option 150 to your TFTP server.

Route the traffic appropriately.

Tommer Catlin Wed, 11/04/2009 - 20:55

Im not sure how the DHCP would work then off CUCM. Typically, you have a helper address to the Scope. So if your vlans are different and subnets, its typically not a problem.

Can you create a scope locally on the other network?

Paul Reck Thu, 11/05/2009 - 17:09

Hi Manish,

I assume as they're different customers they're unlikely to look at trying to run an L2 tunnel over MPLS and try to extend the VLAN?

Tommer's initial suggestion of an IP re-design on one of the sites is your best next step.



Tommer Catlin Fri, 11/06/2009 - 07:49

At least for the phone voice vlan redesign. The customer should not have a problem with a different scope for the phones. It is best practice anyways.

Tommer Catlin Fri, 11/06/2009 - 10:27

Because callmanger cant route to that phone if its has the same IP address as another site.

Same as if your PC had and another PC at a remote site had IP address How would they transfer files???? They cant. Basic IP priciples


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