[SIPForum-discussion] SIP Testing (INVITE without SDP)

[Shakil, Rashid]

Hello All,

 

I am having call failure issues when my softswitch sending a SIP INVITE
without SDP for a redirect call (Inbound call from SIP redirected back
to an offnet number). The call scenario is as follows

 

1.	An Inbound call (PSTN to IP) comes in from SIP carrier. The user
on SIP side (our customer) enable the Find me feature to redirect the
inbound to an offnet number
2.	An outbound call goes out from my softswitch to the SIP carrier.
The INVITE for that outbound call has diversion header but no SDP
3.	In response to the outbound INVITE (without SDP) the upstream
Gateway sent me 480 Temporary Unavailable with this explanation "After
receiving the PSTN call, the gateway sends out the first INVITE. It
receives back the forwarded INVITE (with diversion header), but the
INVITE does not have any media specified. So the gateway then sends out
a new INVITE to the destination number, but sets media a=sendonly. The
call is being rejected because on the egress side, the INVITE goes out
with a=sendonly (because there was no SDP on the Ingress INVITE), but
the 200 OK comes back with no "a" setting, which means a=sendrecv".

 

I believe we can redirect a call with diversion header and without SDP.
Is this explanation from my upstream provider is correct do I have to
send an SDP for the redirected call... Please reply me so that I can
move forward with this issue. 

 

Regards,

 

Rashid Shakil.

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://sipforum.org/pipermail/discussion/attachments/20080313/81e218b5/attachment-0002.html>