SIP Trunk and Registration Settings?

Does anyone have a simple understanding of how the Registration settings under Asterisk SIP Settings can affect the registration and connection to a SIP Trunk? Thanks!

Yes, lots of us do. What problem are you having that we can help you solve.

Registration Google Search Result

I have some systems where my SIP Trunks go Unreachable for small to medium quantities of time and I’m wondering if I altered these settings I may be able to keep my connection to the SIP Trunks up.

I have increased my UDP session timeout within the router and have found that to be effective at times but wondering if these settings would at all affect SIP Trunks going Unreachable and then back Reachable.

Registration is almost never “timed”, so I doubt that changing anything in your registration is going to make a difference. If increasing the UDP session timeout helped, I’d suggest that the problem might be another issue in your local network.

What have you done to troubleshoot this?

Sadly nothing other than increasing the setting on the router. Not sure where to start to find the issue.

I’d be inclined to start with looking through the /var/log/asterisk/full log file and see if you can get a feel for what’s happening right before the line drops.

You might be able to catch it on a SIP debug, but the …/full log will probably steer your search clearer, quicker.

If you feel that the registration is expiring quicker than you are sending your register strings, then a little trick I have found is to add ‘~300’ to the end of your register string. ‘300’ being the number of seconds you wish to send your register string.

So on my PBX, I usually have the default registration times set to 120 seconds, where some SIP providers here do not like registrations being sent so often, and require registrations only once every 3600 seconds (1 hour). The tilde (~) allows you to set the registration period for that specific trunk without affecting anything else on your system.

I did have an issue with one of my providers where it would allow me to have up to 6 simulations registrations and registrations would expire after one hour. My registration times were set so that I would be trying to register 7 times in the hour, and the 7th one would always fail and take my trunk offline - until I registered again after my 1st registration had expired, then all was fine until the 7th registration ( and round in circles we go).