Hi Singh,
I think u are referring to MegaCluster.
A megacluster can also be deployed where customers simply require non-locally redundant call
processing functionality, rather than using Survivable Remote Site Telephony (SRST), to scale beyond
the maximum eight sites allowed in a standard cluster deployment and up to 16 Unified CM subscriber
nodes per megacluster. For example, consider a large hospital that has twelve locations and each location
has only 1,000 devices. This total of 12,000 devices could be accommodated within a standard cluster,
which has a maximum device capacity of 40,000 devices. However, in this case it is the need for
additional Unified CM subscribers, rather than additional device capacity, that requires a megacluster
deployment. In this example, a Unified CM subscriber node could be deployed in each location, and each
Unified CM subscriber could serve as the primary subscriber for the local endpoints and as a backup
subscriber for endpoints from another location.
you can refer SRND.
regds,
aman
