Got an interesting issue here....We've got 2 Cisco phones that will register and come up fine, but after 30 min or so, they will unregister and go through the whole registration process again but will never register until you power cycle the phone. The phones connect back to a 4510 where we're routing back to our core. There is a voice vlan that is configured on that switch and the dhcp scope on our dhcp server has all the correct settings and options. The leases show up on the dhcp server and the lease time is set to 24 hrs. Any ideas on what I should be looking at or what could be the problem? The phones are a 7961 and a 7911
Check the phone webpage for status messages, debug display, and possibly console logs to see what the phone thinks is the reason for it to be unregistering. Then on the CUCM side check the Application Event Viewer (Syslog) and if you're on CUCM 8.x in the Event Viewer Application log check the Alternate Syslog file to see the reason code the phone reports back when it registers after the unregister for why it last unregistered.