[Freeswitch-users] Problem with Cancel

[kawarod]

Hi List,

I have an issue with FS connected to a SIP gateway.
When I receive a call from the SIP Gateway and try to hangup the call before he call is answered, so that a Cancel is emitted by the SIP GW, I have a SIP 481 Call Transaction does not exist.

I understand that FS is unable to match this Cancel with the correct Invite, so that FS can not process the Cancel.

Below is the SIP trace. It seems to me that the issue is because the Invite and the Cancel (generated by the same SIP GW) have different branch in the Via field.
But I have no way to update the SIP GW and I absolutely need it for connection to the core network.

May you please help to check if the issue could be related to the Via branch. It seems that they should be the same based on RFC.
Do you have any idea to bypass this issue (any SIP profile magic trick :p).
I made a "make current" this morning to check if this could help.

U 10.69.208.204:5060 -> 10.69.208.200:5063
INVITE sip:770056 at 10.69.208.200:5063;user=phone SIP/2.0.
Via: SIP/2.0/UDP 10.69.208.204:5060;branch=z9hG4bK-600-8524.
To: <sip:770056 at 10.69.208.200:5063;user=phone>.
From: <sip:265912 at 10.69.208.204:5060;user=phone>;tag=s24df07240-600-9408.
Call-ID: 10.69.208.204:5060-4df07240-600-4680.
Max-Forwards: 70.
CSeq: 1 INVITE.
Content-Length: 679.
Remote-Party-Id: <sip:265912 at 10.69.208.204:5060;user=phone>;privacy=off;screen=yes.
X-Fmc-Signaling-Info: location-pdu=83178679040000;location-pdu=689740000.
Contact: <sip:265912 at 10.69.208.204:5060>.
Allow: INVITE,ACK,BYE,CANCEL,OPTIONS,REFER,PRACK,INFO,MESSAGE,SUBSCRIBE,NOTIFY,UPDATE.
Content-Type: application/sdp.


U 10.69.208.204:5060 -> 10.69.208.200:5063
CANCEL sip:770056 at 10.69.208.200:5063 SIP/2.0.
Via: SIP/2.0/UDP 10.69.208.204:5060;branch=z9hG4bK-5800-392.
To: <sip:770056 at 10.69.208.200:5063;user=phone>;tag=6XN6KF2N267cp.
From: <sip:265912 at 10.69.208.204:5060;user=phone>;tag=s24df07240-600-9408.
Call-ID: 10.69.208.204:5060-4df07240-600-4680.
Max-Forwards: 70.
CSeq: 1 CANCEL.
Content-Length: 0.
Reason: Q.850;cause=16;text="Normal call clearing".
.


U 10.69.208.200:5063 -> 10.69.208.204:5060
SIP/2.0 481 Call/Transaction Does Not Exist.
Via: SIP/2.0/UDP 10.69.208.204:5060;branch=z9hG4bK-5800-392.
From: <sip:265912 at 10.69.208.204:5060;user=phone>;tag=s24df07240-600-9408.
To: <sip:770056 at 10.69.208.200:5063;user=phone>;tag=6XN6KF2N267cp.
Call-ID: 10.69.208.204:5060-4df07240-600-4680.
CSeq: 1 CANCEL.
Content-Length: 0.

regards,

rod