We have a customer with a cluster of 4.1 servers across 2 sites (3 servers in total).
rather than a big bang approach we are building a seperate 3 server Cucm ver 7.0 cluster and then will slowly migrate users across to the new cluster.
Is it possible to have say some of the users on the old cluster and some on the new? but be transparent to the users?
I will need to configure PSTN calls to route across the CUCM 7 - 4.1 trunk and out through the gateway attached to the old 4.1 system. and also have ddi calls go first to the old system and then route through the new trunk to the right DDI.
I appreciate I will have to define the number range so that no overlapping occurs, are there any reasons why this cannot be done?
I guess you are building the 7.X from scratch with new IP address and not using DMA.
If that's the case, you'll need to create an ICT trunk between the 4.X and 7.X servers to route calls between them. You'll also need to avoid
overlapping extensions as now the phones will be registered to different clusters. This is explained on the SRND, in general we always need to
avoid the use of overlapping DNs.
If the dial plan you have is for example 1XXX, migrate a consecutive block of users,for example 1000-1099 to the new cluster so you can easily add
a Route Pattern that's 10XX and point the calls to the ICT. This is needed to aovid ambiguous call routing.
To route calls to the GW on the 4.X server, you'll need to pass them through the ICT, so in the 7.X cluster you'll have your 9.X RPs pointing to the ICT.
Hope this helps!