We are in process of migration from CUCM v7 to CUCM v10.5. We have around 3000 SCCP Phone in centralized CUCM v7 also we are migrating the Phones to 8800 seris SIP phones after success ful migration of CUCM. We created an inter cluster trunk between the clusters to make internal calling as SIP trunk is not supported in CUCM v7.
we tested the internal calling between the clusters. it is working fine between SCCP Phones but when we replace the phones in CUCMv10.5 to 8865 phone only incoming calls is working between the cluster. 8865 SIP --> CUCMv10.5 --> ICT --> CUCMv7 --> 7975 SCCP is not working.
Any advice is appreciated. the stage by stage migration plan is stuck because of this issue
