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Migrating 7911 phones between clusters

Level 1
Level 1


I have installed a new V8.6 cluster as part of a V7 to V8 upgrade. I wanted to test that various phones can register with the new cluster and move them back onto the V7 cluster as a backout.

Both 7911 & 7941 phones upgrade their firmware and register on the new V8 cluster. The new cluster has been configured with different IP addresses to allow for a phased phone migration.

However they fail to re-register on the V7 cluster when the DHCP option 150 has been changed.They do not downgrade firmware as the phones have maintained the new Call Manager IP addresses. This is visible by browsing to the phones IP address and the V8 Call Manager IP addresses are configured.

A wireshark trace shows no TFTP requests from the phone to the V7 UC Servers.

A reset to factory default resolves the issue and allows the phones to re-register on the V7 cluster.

The firmware versions deployed are:

V7.1(5)     cluster SCCP11.9-1-1SR1S

V8.6(2)     cluster SCCP11.9-3-1SR2-1S

Any ideas why the phones fail to downgrade and re-regsiter on the V7 cluster would be appreciated.



5 Replies 5

Ayodeji Okanlawon
VIP Alumni
VIP Alumni

This is most likely an ITL issue. CUCM 8 introduced the new Security By Default feature and the use of ITL (Initial Trust List) files.

With this new feature, care must be taken when moving phones between different CUCM clusters. Without following the proper steps it is possible to encounter a situation where thousands of phones must manually have their ITL files deleted

Please read more here..and follow the recommendations

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