CUCM as Backup of CME

[aelankoud]

Hi all,

I already installed CME, with 200 IP Phones (type 7900G), now i installed CUCM 11.5.

I want that when the CME turns off, all IP Phones register in CUCM 11.5 automatically.

It means that CUCM becomes backup of CME

thank you for help.

Youssef ELANKOUD.

[Brandon Buffin]

You would need to configure:

1. Secondary DHCP option 150 to point to CUCM
2. All phones/DNs in CUCM
3. Calling search spaces, partitions, route patterns in CUCM for external calls
4. Gateway in CUCM (I'm assuming this is the same box performing CME?)

Are CUCM/CME located at the same site? Any reason for this failover? Why not use CUCM with CME as the failover?

Brandon

[aelankoud]

thank you, Brandon,

CUCM/CME located at the same site, and how i can use CUCM, with CME as the failover ??

if CME fails, the All IP Phones retrieve CUCM configuration automatically, in addition the IPhones are already configured to that ??

thank you for helping.

[Brandon Buffin]

Take a look at the following link regarding CME as SRST.

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucme/admin/configuration/manual/cmeadm/cmesrst.html

In your original scenario if CME fails the phones would register to CUCM (assuming you had configured the phones/DNS ahead of time). This configuration would not happen automatically.

On the other hand if you use CME as the failover the device, the configuration is more automated. See the link above for the required steps.

Brandon

[aelankoud]

thank you Brandon,

My question is, how the IP Phones retrieve the CUCM configurations, knowing that they are already added to the CUCM, when the CME is off, it means that the IP Phones must reinitialize the CME configuration, and Then retrieves the CUCM configuration automatically

Best Regards.

[Brandon Buffin]

Secondary TFTP address via DHCP option 150. However, thinking through this I'm not sure the phone is going to use the secondary TFTP address until it is restarted. You would need to manually restart the phones for the change to take effect. Not a great option.

[aelankoud]

Hi Brandon.

thank you for your reply.

Yes, not a great option, we have more than 200 positions, deployed in the offices of the administration, it is very difficult to restart them manually.

thank you again.

Youssef

[Marwan Urabi]

Hi Brandon.

I have same case , but how can avoid TLS file that will install automatically from CUCM to phone and then later phones can't register again to CME until manually delete this TLS file from security settings phone by phone ?

Regards

[Rajan]

As mentioned by Brandon, the failover from CME to CUCM might not happen automatically. I have never seen this kind of deployment in use and neither its a recommended one.

Its always advisable to register the phones in CUCM and keep CME srst as a backup so that the failover happens automatically.

HTH

Rajan

[aelankoud]

Hi Rojan.

Thank you for your reply,
So if I want to do the opposite, CME as the CUCM Backup, is what CME will do the switchover automatically if CUCM is off, that means the IP phones will recover its configurations again from CME.

thank you again.

Youssef.

[Rajan]

Hi Youssef,

Yes. When the phones lost connection to the CUCM or the CUCM server/service is down, the phones will automatically register with the CME using the SRST configuration and retains its settings.

You can read more regarding how this works in the below links:

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucme/admin/configuration/manual/cmeadm/cmesrst.html

https://supportforums.cisco.com/document/98681/how-implement-cucme-srst-mode

HTH

Rajan

Pls rate all useful posts

[aelankoud]

Hi Rajan,

The SRST functionality is used just for WAN networks, eg CUCM installed in a Site 1 and CUCME site installed in another site Site 2, in our case the two CUCM / CUCME servers are installed in the same LAN networks.
Does this feature work well in LANs?

Thank you

Youssef

[Brandon Buffin]

SRST can be used on the LAN. In this case, it protects against a CUCM failure instead of a WAN failure. This scenario is less common. The best practice is to use a CUCM subscriber server(s) for failover.

Brandon

[collinks2]

Hi Brandon, please can you assist me with this issue?

I have a Telepresence conductor and telepresence server (vts) linked with cisco cucm. Cucm users can call CME users but cant video conference with them. Also cme users can not video conference among themselves due to the lack of dsp which is currently PVDM-32. CUCM users can do video conference via telepresence Conductor. Cme users can join the conference but after some minutes, the video will be disabled. is there no way CME users can make use of the Telepresence Conductor for their video conference ?