Forcing a phone to use new CUCM servers

[Jason Cox]

Hello All,

We have a customer that, due to their network configuration forces us to put their new CUCM VMs on a different subnet. The DHCP scopes are on Cisco routers so changing the option 150 IPs is not a problem, but this is what I'm not sure about: will doing a clear ip dhcp binding *, then resetting the phones from the old CUCM cluster force the phones to pick up the new tftp servers? If not, will doing a shut / no shut do the trick after clearing the bindings? What is your experience in this situation?

Appreciate your comments,

Jason

[Dennis Mink]

you will need to test it, mate.

the dhcp binding is something that lives on the switch/router and is more used for dhcp inspection etc. and has nothing to do with the phone IP address "awareness".

can you change the lease time on the phones (per voice vlan) to something low, so that you can easily force them into the new subnet and option 150?

[Jason Cox]

Dennis thanks for the input - I was afraid that might be the case. The lease is currently 365 days (!), so even if I set it now, it would be some time before the leases start to expire. We're supposed to do the cutover tomorrow so I'll let you know how it goes. Don't really want to do a factory reset on 400 phones across nine campuses :-).

[nalonsopresidio]

What version of CUCM is it? If you have to separate clusters (I hear "old" and "new" cluster), and the version is 8+ you will run into a certificate ITL CTL trust issue and the phones will not accept the new TFTP servers/CUCM and will not register to the new cluster.

You have two options.

1- Enable enterprise parameter on old cluster to roll cluster to version pre 8. Apply/reset (before changing option 150), then when they come back change option 150 and reset on old cluster.

2- Bulk export and bulk import the TFTP certs from the new to the old cluster.

Once this is done, the phones will home to the new cluster after you reset them (after changing option 150). Clearing the binding will do the trick.

[Jason Cox]

The old cluster is 7.x so no worries there, although as a precautionary (I'm a bit paranoid about ITL/CTL phone issues) step on the new 11.x cluster I set the cluster to pre-8.x rollback mode prior to any phones registering to it.

As far as the option 150 change, it was easier than I thought. Prior to the move, I changed the Option 150 to point to the new cluster then reset one phone (7960) from the old 7.x admin GUI. That one phone registered straight away to the new cluster. I didn't have to clear any DHCP bindings or do any other work. I duplicated the result with a newer phone (7945). So we cut over the phones on cut day without issue.

Thanks for the input guys.

[srinivascisco]

Hi... Could you tell me what are the certificates we need to import from New to Old?

I am doing 2 old cluster switches to new clusters

1. CUCM 6.X to 11.5

2.CUCM 7.1.3 to 11.5

[Manish Gogna]

Hi Srinivas,

Migration from 6.x or 7.x to 11.x version is best done via the PCD tool as detailed in the admin guide for PCd

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucm/pcdadmin/11_6_1/cucm_b_pcd-admin-guide-1161/cucm_b_pcd-admin-guide-1161_chapter_011.html

You need to follow the migration task steps as detailed. Couple of points you need to note:

>> if you are keeping existing IP's and hostnames then it would be a 'simple migration' , if the IP/hostname would be changed then it would be a 'network migration'

>> There are recommendations for secure and non-secure clusters as well in th guide

Manish

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