I have been facing an issue in a specific call scenario involving 7960 phones. The call scenario being as follows:
1) Phone A, B and C are in same CSS.
2) Phone A and B in same partition, while Phone C is in Null partition.
3) Calls to Phone C from Phone A and B happens, but vice versa fails.
This happens only when Phone C is 7960, otherwise it works well.
Let me know how this can be resolved. The UCM being used is 4.3(2)ES 21 and the phone load on phone 7960 is P00308010200