[SIPForum-discussion] question on PRACK

[Garron, James]

There is nothing wrong with sending multiple reliable 18x messages.  The 183 is simply a progress message, say in the case the peer sent an INVITE that was responded to with a 300, in this case it could return a 183 send INVITE to the first contact and then send 180 ring when that is received.

Did the 180 Ringing contain Rquired 100Rel?  If not the SBC could be rejecting as it has already received the 183 the Required 100Rel.  Are there any logs that you can share.


-----Original Message-----
From: discussion-bounces at sipforum.org on behalf of Raghul Prasanna
Sent: Wed 5/11/2011 6:57 PM
To: discussion at sipforum.org
Subject: [SIPForum-discussion] question on PRACK
 
Hello all,
One of our carrier requires support for PRACK.
When the carrier sends 183 Session Progress, we send PRACK and receive 200 OK for the PRACK.
Then they again send 180 Ringing and our SBC rejects the call.
I believe we are right here to reject the call, because the carrier shouldnt be sending 180 ringing after receiving PRACK for 183 Session Progress. Please let me know.
Also if possible please point me to any rfc which says PRACK to 183 should not be followed by 180.
Thanks,Raghul