Hi everybody,

I was doing some tests with your Free Softswitch and I have met with the following problem.

This problem can be reproduced with Linphone SIP softphones and GrandStream GVX-3000 SIP phones (devices I have).
However, it does not happen with your softphone MizuPhone.

All the phones are correctly registered in the Server. The problem is that I am calling from one phone (1) to another (2).
The user of the phone (2) does not accept the call and cancels the call. The phone (2) stops ringing but the phone (1) still rings endlessly. It seems that the phone (1) discards the message of the server to terminate the call.

Checking the different logs of the phones and the server it seems that the Softswitch sends a BYE message to the phone (1) and the phone (1) discards that message because it is expecting a CANCEL messages instead.

I do not know if that behaviour can be changed by configuration or not but it seems that some SIP phones/softphones have a more strict implementation of the SIP protocol and does not accept the BYE message when they are in an early stage of the call (ringing phase).

I only wanted to share with you this scenario in order to let you know about that behaviour.

Best regards,
Eduardo