Concerns regarding Wireless Phones moving between CME and CUCM environments

[shamax_1983]

Hi Guys,

We have a situation where the customer wants to carry the Cisco wireless phone (7925G-EX) between CME and CUCM environments. The CME and CUCM reside in two different sites with different extension rages and the two systems work independently (there is a SIP trunk between them).

So my question is,  

If we setup this device on both systems with applicable extension etc, and if the phone was first used with CUCM and then taken in to CME environment, would it work without any issues as expected?.  

I'm just thinking about the phone firmware side of things.. would it just download the firmware each time it goes from  one place to the other? or is there any firmware that can support both worlds without having to download the firmware each time ? 

Any answers or suggestions will be much appreciated.

[Tagir Temirgaliyev]

do you have ip lan to lan connectivity between two sites?

so the phone can keep the same number in both sites

[shamax_1983]

Hi Tagir,

Thanks for your reply..

They do have LAN to LAN connectivity. But the WAN is unreliable and that's why they keep separate boxes (CME and CUCM) at both ends so they can work independently. Therefore having two extensions is a requirement in our scenario. ( Although this is not ideal) 

[Tagir Temirgaliyev]

I am not shure about the Cisco wireless phone (7925G-EX)

but when phone 7965 registered in cucm and I move it in another place with cme

it get new ip address and Ip option 150 wich points  to cme but phone still connects to cucm

and only after factory reset  it  registers in cme