Richard,
Here is a bried description of the process I followed,
1. Build one of the new servers with the OS and CCM 4.1.3 to replicate the existing/production environment as close as possible. I refer to this as temp CCM4.1.3pub.
2. Restore the existing configuration on the new built server using the latest copy of a BARS backup on the production environment.
3. Set up a lab environment, using the new server acting as the publihser with some phones, monitor the registration, tests some features, etc. Note that the network settings will be the same as the production server so you need to set up this lab isolated from the production LAN.
4. Install and RUN DMA on this temp CCM4.1.3 pub.
5. Install CUCM6.1.2 on the other new server, using the DMA backup done in the step above.
6. Perform system and usability tests once the new server is built. You can always go back to the temp 4.1.3 pub if you need to re-run DMA if any errors are found.
7. Build the second node (subscriber) on the server acting as the temp 4.1.3 pub.
8. Finally switchover the new servers with the ones in production. No changes will be required on the network settings as the new ones are built with the same settings as the ones in production.
Hope this helps.
Esteban
