SOME call drops after 31 minutes....

[IHSupport]

SOME calls dropping after 31 minutes and 20 seconds
Hello, I have a system where some calls are dropping at the 31 minute mark.
This doesn’t happen on all calls though.
The calls take place on outgoing SIP calls using a Yaelink T22P.
We have had instances where a call can last over 31 minutes which are no difference to the calls that fail.
All the timers on the system are correct and all the phones are using 3cx firmware.
Can anyone suggest what we should look at?
Thanks in advance.

 

[YiannisH_3CX]

Hello @IHSupport

Is this happening with calls to the provider does it also happen with extension to extension calls?
Calls dropping at the 32 second mark (very close to what you are describing) usually do so because an ACK message is not received after the 200 OK message

Make sure that the firewall checker checks out all ports and if the issue persists run a capture and look at the call flow. The side that is answering the call will send a 200 OK. The calling side will then send an ACK message in response. If this does not happen then the call will drop after 32 seconds.

 

[IHSupport]

hello,

Hello @IHSupport

Is this happening with calls to the provider does it also happen with extension to extension calls?
Calls dropping at the 32 second mark (very close to what you are describing) usually do so because an ACK message is not received after the 200 OK message

Make sure that the firewall checker checks out all ports and if the issue persists run a capture and look at the call flow. The side that is answering the call will send a 200 OK. The calling side will then send an ACK message in response. If this does not happen then the call will drop after 32 seconds.

Hello,

this may be an error on my part but the call drops after 31 minutes and 20 seconds.

this doesn't happen all the time though. i will however ask that they test internally and let you know the results.

 

[YiannisH_3CX]

OK i might have read that wrong. I thought it was 31 seconds for some reason.

In your case then the issue might be caused by the session expires value. This value is negotiated between the provider and the PBX and it is used so that the call is renewed at a certain point from the user agent negotiated. This eliminates stuck calls from going on for ever as if you do not renew the session then the call is dropped.
Check the negotiated value if there is one and check if the correct user agent is renewing the session.

 

[IHSupport]

OK i might have read that wrong. I thought it was 31 seconds for some reason.

In your case then the issue might be caused by the session expires value. This value is negotiated between the provider and the PBX and it is used so that the call is renewed at a certain point from the user agent negotiated. This eliminates stuck calls from going on for ever as if you do not renew the session then the call is dropped.
Check the negotiated value if there is one and check if the correct user agent is renewing the session.

Thanks for that i will look in custom parameters for times that could relate to this and test.