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

manish.gupta · ‎11-04-2009

HI,

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.

Thanks,

Manish.

Tommer Catlin · ‎11-04-2009

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.

manish.gupta · ‎11-04-2009

Hi,

Thanks for ur reply. Actually, Both the sites are of different customer and they are not ready to re-design their network and both the sites are having 24 bit mask i.e. 192.168.1.0/24 ..

Please suggest the best possible scenario.Thanks,

Manish

Tommer Catlin · ‎11-04-2009

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 · ‎11-05-2009

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.

regards,

Paul

Tommer Catlin · ‎11-06-2009

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.

manish.gupta · ‎11-06-2009

Hi Tommer,

Thanks, but how come a voice-vlan will solve our purpose...both the sites are having common IP Addressing with a single DHCP server i.e. Cisco Call Manager. My objective is to register all the IP phones of both the sites successfully without any conflict of IPs.

Please suggest.

Thanks,

Manish

Tommer Catlin · ‎11-06-2009

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

Same as if your PC had 192.168.1.3 and another PC at a remote site had IP address 192.168.1.3. How would they transfer files???? They cant. Basic IP priciples