[reSIProcate-users] Resiprocate Stack Not Forwarding Certain SIP Messages

[Edward James <ERJ@xxxxxxxxxxxxxxx>]

Hi All,

          I have a SIP message flow in which the Resiprocate stack is a UAS (so the call is inbound to our application called RT-SIP-20 which uses Resiprocate) and it looks like the Resiprocate stack isn’t forwarding certain SIP messages up to the application. Basically the call is as follows:

 

1.    Inbound Audio Call – this is just a standard inbound call and is set up successfully.

2.    The UAC Sends a reINVITE for FAX – so we receive a reINVITE containing FAX SDP offer and we reject this with a 488 as we don’t support it.

3.    The UAC sends an ACK to the 488 which Resiprocate does not forward to our application.

4.    The UAC sends a reINVITE (containing audio SDP) which Resiprocate does not forward to our application and which Resiprocate rejects with a 491.

 

Does anyone know why Resiprocate would not pass on to our application either an ACK to a 488 to a reINVITE or any subsequent reINVITES ? Just for clarity here’s the SIP message flow (RT-SIP-20 is our SIP engine which uses Resiprocate):

 

UAC INVITE SDP=audio --------à Resiprocate --------à RT-SIP-20 UAS

UAC ß-----------------------------  Resiprocate ß-------- RT-SIP-20 UAS 100 Trying

UAC ß-----------------------------  Resiprocate ß-------- RT-SIP-20 UAS 183 Progress SDP=audio & 100rel

UAC PRACK ---------------------à  Resiprocate --------à RT-SIP-20 UAS

UAC ß-----------------------------  Resiprocate ß-------- RT-SIP-20 UAS 200 OK PRACK

UAC ß-----------------------------  Resiprocate ß-------- RT-SIP-20 UAS 200 OK INVITE

UAC ACK ------------------------à  Resiprocate --------à RT-SIP-20 UAS

 

So at this point it’s all good with an audio call set up. Then we get this reINVITE/488/ACK exchange:

 

UAC reINVITE SDP=image --------à Resiprocate --------à RT-SIP-20 UAS

UAC ß--------------------------------  Resiprocate ß-------  RT-SIP-20 UAS 488 Not Acceptable Here

UAC ACK ---------------------------à Resiprocate  ** Not Forwarded to RT-SIP-20 ??? **

 

So the ACK to the 488 isn’t forwarded to our engine. The we get this reINVITE/491/ACK exchange:

 

UAC reINVITE SDP=audio ---------à Resiprocate ** Not Forwarded to RT-SIP-20 ??? **

UAC ß--------------------------------  Resiprocate 491 Request Pending sent from Resiprocate

UAC ACK ---------------------------à Resiprocate  ** Not Forwarded to RT-SIP-20 ??? **

 

So now it seems that Resiprocate is not forwarding the reINVITE and responding with a 491.

 

Does anyone know if this is RFC compliant (in which case I’ll change our engine) or if not can anyone point me to where I should look in the Resiprocate code to modify it to forward all the messages to the application.

 

Any other comments welcome.

 

Thanks

Ed James