I need to migrate distributed architecture to centralise architecture

[cameroun]

I have CUCM V8.5 on one site and et CCME on many others sites. I need to migrate to a centralize architecture and use CCME as SRST routers. Which licence do i need to do it ??

[Jianbin Huang]

You should expand your CUCM licenses (DLU), allowing the phones on the outer sites to registering to CUCM.

You can use CME as the fallback method, no extra license need.

[Brian Meade]

Since you already have CME/SRST licensing for the routers, you shouldn't need any additional licensing except for enough on CUCM to allow for all the new phones to register.