Session Timer - Call Drop after 15 Minutes

[pcmis]

Is there a setting anywhere is 3CX that you can turn off the the session timer re-invite after 15 minutes? I have seen other posts on this topic, but none with a fix.

Response from my SIP provider:
It happens when you r device or system sends a session timer header in the INVITE of the call, which is usually for 15 minutes.
When the session timer is in the INVITE the server will send a Re-INVITE every 15 minutes into the call, and is expected that your system follows the Re-INVITE process. If it fails to do so the call gets disconnected after a few seconds (usually dropped at 15:32).

In this case you can check in your system, look for a session timer setting, disable it or set it to "refuse".

 

[cobaltit]

I'm assuming this isn't a supported provider?

3CX has no such knob that I'm aware of, and is fully RFC compliant so I'm assuming your provider isn't handling something properly. From my basic understanding, if 3CX is sending the invite, then they should be the one's refreshing the timer, not the SIP server.

https://tools.ietf.org/html/rfc4028

 

[pcmis]

I guess it’s possible it’s the provider. I am using voip.ms. I think another thread had same one.

 

[cobaltit]

Oh.. well voip.ms is supported so if that's the case, I would try to get a capture of this happening and open a ticket with 3CX.

Also, if this is an older installation you could try adding a fake voip.ms trunk and comparing the settings. 3CX updates the templates based on provider changes, and that doesn't affect existing trunks.

 

[pcmis]

Thanks I will give it try!

 

[YiannisH_3CX]

Hi @pcmis

There is no setting to turn off the session timer in 3CX but it is working properly with Voip.ms. The session timer is being used only if the 2 parties support the "timer" function.
The refresher is being decided during the Invite phase of the call where the 2 platforms agree on who is going to refresh the call. To be honest i have never seen 3CX fail to refresh a call but i have seen cases where the firewall was causing issues and the refresh was not being received by the provider or by 3CX.
Make sure that you pass the firewall checker and if the issue persists consider opening a ticket with our support department so they can check the communication.