I have been tasked to migrate one of my customer's IP telephony network from IP addressing scheme to My customer has deployed Cisco Call Manager and Cisco Unity Express. I just want to know what all things I should take care of, so this transition happens smoothly? I do not have much experience in handling such migrations, any help is highly appreciated.

  • 1
    We need a lot more to help you. A network diagram and detailed description of how everything is connected. Also what type of network equipment is used and the configurations.
    – user36472
    Mar 25 '18 at 10:55
  • The main things I'd also ask are how many phones are involved, whether they are remotely managed, and what amount of downtime is considered acceptable.
    – jonathanjo
    Mar 25 '18 at 11:21
  • The customer wants me to do the reconfiguration only for one site.They have 87 IP phones and all are managed by the CUCM at their branch. I have one full day to reconfigure things.They also have a couple of SIP trunks, if I change the IP address of the CUCM how the tunks will be affected? Mar 25 '18 at 13:21
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Apr 1 '18 at 23:10

One thing that I have learnt the hard way is migrating CUCM and UNITY. Make sure you change the ip address on the web interface by going to SYSYTEM > SERVER and changing the ip address to the new one (eg.

Then you need console access to them. If they are running virtually then this is a benefit. Login to each server an issue these commands:

set network gateway *<gateway>* set network ip eth0 *<ip>* *<subnet mask>*

The server will then reboot and have the new IP you set. But make sure you change in on the WEB gui first to avoid being locked out!

I do not know about the SIP trunks that you have setup and how they have been configured.

  • No problem, let me know if you need more help Mar 27 '18 at 19:36
  • Does changing the IP address of the CUCM and Unity invalidates the existing License? Do I need to get a new license from Cisco after the change? Mar 28 '18 at 9:42
  • No, this shouldn't change anything with Cisco UCM Mar 28 '18 at 10:48

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