We use the term "Collapsing" clusters. I have been doing more of these lately. Basically, you need a good tool to export the data from the CUCM cluster you want to export. Devices, lines, trunks, Route Patterns, Translations, etc. For the existing cluster you are importing to, it should be easy.. you cant rebuild this cluster, so you must follow the dial plan already set up within that cluster. Figure out how this remote site will be a new "site" in the existing cluster.
The phones are the easy part. You can simply build out all the pieces in CUCM on the existing cluster
PT/CSS
Gateways.
Basically, its a rebuild, but you can streamline some of it... just be heistant when using the import/export tool. If its not a large site, Id rebuild everything, route patterns, transaltions, etc for this site in the 7x system. Then import the phones/lines to the system, but place the lines in a dummy PT. When you go to cut over, BAT the lines to their perm Route Partition on the Line.
As for the licenses, If the clusters are on the same contract, you can try email licensing@cisco.com and see if they can work with you on mirgrating the licenses to the 7.x cluster. If they are not, or the license on the 6.x server on a different contract, and with for example an expired UCSS/ESW contract, you may be out of luck. You would need to renew that cluster (6.x) or purchase new on the 7.x for the phones/users.
If its CUWL for 6.x, the CUWL group within Cisco can probably help out getting this process moving.
If you are in a pinch, you can request a temp DLUs from licensing@cisco.com for your 7.x so you can at least move the phones over for 60 days and possibly extend that again while contracts are figured out, etc.
