When does the N510 sends Registration request with expires = 0. This means a SIP de-registration.
There are different scenarios that an N510 sends a de-registration request.
- Web-interface: Uncheck "Active" option for this SIP account
- Web-interface: Delete SIP account.
- Device expects SIP values are no longer valid:
address of record ( "displayname"<sip:email@example.com> )
contact addresses ( e.g. firstname.lastname@example.org:53260 ) on the registration server (location database)
De-registration is started with possible new registration
So initiations for de-register procedures are:
- address-of-record was modified ( displayname, user-id, login-id, domain )
- contact address might have changed:
- new local sip port
- new local IP address
- new public IP address (detected by STUN) (checked any 240s, configurable)
- new public port ( not checked periodically )
Disable / delete the STUN settings in the device.
Upgrade device to software >211 because of STUN improvement to avoid these issues.