Scenario#45: 7841 SIP phone in Registration loop

I was working on this customer issue last week where they added a new 7841 phone but it was not registering properly or should I say it was registering briefly before unregistering. Call Manager was 9.1.2.11900-12 which does not support 78XX phones so customer actually applied the device pack cmterm-devicepack9.1.2.12039-1.copĀ  so that they can add 78XX phones. Looking at the logs I found that it is registering with Pub and not Sub even though Sub was the Primary CCM in Call Manager group. At Pub I can see something like this: Pub: REGISTER sip:192.168.11.2 SIP/2.0 Via: SIP/2.0/TCP 172.18.52.91:51736;branch=z9hG4bK739dd207 From: <sip:49715220XXXXX@192.168.11.2>;tag=544a003629fd000a741be677-22e1dea8 … Continue reading Scenario#45: 7841 SIP phone in Registration loop