Jain-sip sends sip messages automatically

Question

I have written a softphone which can communicate with a PBX (simulated by SIPp). For this I use the jain-sip frameworkt for java. My problem is, that jain-sip sends sip messages automatically. For example, after receiving a RE-INVITE message my program sends an OK message back, but jain-sip sends automatically a TRYING message back. Why???

Jain-sip sends also some OK messages automatically. See call flow below (the PBX is sending the INVITE message to my softphone app):

• INVITE -->
• <-- TRYING
• <-- RINGING
• <-- OK/SDP (port number 2000)
• ACK -->

• Sending RTP on port 2000

• RE-INVITE -->

• <-- TRYING
• <-- OK/SDP (port number 2002)
• ACK -->
• Sending RTP on port 2002
• <-- OK/SDP (port number 2000) // jain-sip sends this message automatically!!!
• ACK -->
• Sending RTP on port 2000 // now the rtp data go to the wrong port
• <-- OK/SDP (port number 2000) // and again jain-sip sends an ok message automatically
• ACK -->
• Sending RTP on port 2000 // rtp data go to the wrong port
• BYE -->
• <-- OK

Why does jain-sip send messages automatically? Have I done something wrong, or is it possible to disable the automatic sending of sip messages?

Answer 1

For 200 OK I am not sure but it seems that ACK send by remote party is not understand by JAIN SIP & it will retransmit OK which is generated for first INVITE.

You can check by looking to transaction ID in via header. Otherwise you can check with logs of JAIN-SIP stack.

Answer 2

I found out that I can stop the automatic sending of the messages by setting the parameter "javax.sip.AUTOMATIC_DIALOG_SUPPORT" to "off". I also know, why jain-sip sometimes sends a TRYING message automatically. This happens when my softphone app needs too long for sending the OK message back to the PBX. What I still don´t understand is the automatic sending of the OK messages I described in the call flow above. Perhaps someone knows?