I have an Aastra 480i located remotely and when I do a TCPDump I see the phone sending Register Packets non-stop to my server. The phone is working but I don’t like the fact that it does it tons of times a second. How do I stop this?
I have the Registration Period set to 60 and and Registration Renewal timer set to 100. I can’t find anything that is causing this. Anyone can help please?
User’s guide is our best friend 
In the “Registration Period” field, enter the requested registration period, in seconds, from the registrar.
sip registration renewal timer
The length of time, in seconds, prior to expiration, that the phone renews
registrations.
For example, if the value is set to 20, then 20 seconds before the
registration is due to expire, a new REGISTER message is sent to the
registrar to renew the registration.
The value set for this parameter should be between 0 and the value set
for the registration period.