CME 10.5 7841 phones will not auto re-register after system reboot

[AT]

I ma running CME10.5 15.4 IOS 2921 router.  I have 7841 SIP phones that will not re-register themselves after a router reload/power-cycle.  I have to power-cycle the phone for them to register, they will not re-register automatically.  The phones maintain their extension info, but can't make calls until a phone re-boot.

AT 

[Manish Gogna]

Hi AT,

If the issue is reproducible then you should get packet captures from one of the 7841's after you reboot the router. This will allow to check the packets exchanged with the CME to see which part of the registration is going wrong.

Manish

[AT]

I discovered that SIP phones do not have a keep-alive function like SCCP?.  I think you can adjust the registrar expires time to help with this. 

[MOHIT SINGH]

Hi AT,

Are the phones on latest firmware? there are similar known issues with 78XX. If not I will recommend you upgrade to latest version and then check.

If it does not help then we will need packet capture from back of phone and "debug ccsip message" from CME to understand the issue.

Are you using DHCP? Have you tried using manual IP?