We use CUCM12.5 to monitor call events of extension terminals (using JTAPI).
We usually connect to CUCM from one server and run a program to monitor call events.
Is it possible to create multiple sessions from multiple servers in one CUCM?
If possible, could you please tell me the maximum number of sessions?
It is certainly possible, and in theory there could be many thousands of CTI connections supported by the cluster - so a quite high number
For details on the expected impact and supported maximums, see the 'Unified CM 8.6.x CTI Improvements.pptx' doc here: https://developer.cisco.com/site/jtapi/documents/whitepapers/ (still applicable for all later release versions)