Hi Zabi, INVITE and Re-INVITE are different transactions. 200 OK for INVITE and Re-INVITE will have the different CSeq value and Branch parameter in Via header.
UA should send the same ACK for INVITE after receiving 200OK. Thanks, Alok Tiwari Aricent -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of zabi Sent: Wednesday, January 06, 2010 11:51 AM To: [email protected] Subject: [Sip-implementors] Re-Invite before ACK send/received Caller (A) Callee(B) | INVITE | |---------------------------> | | 200 OK | |<---------------------------- | | ACK(dropped) | | ------------x-> | | re-INVITE | | ----------------------------->| | 200 OK | | (retx for 1st Invite) | |<------------------------------| The scenario is follows 1. A sends Invite to the B 2. B responds with 200 Ok(invite txn terminated) 3. A sends ACK for 200 Ok which gets dropped on the network ( B is retransmitting 200 OK). 4. Since A has already send ACK A sends re-INVITE. 5. Meanwhile A receives 200 OK for the 1st INVITE. 6. Since the there is no txn existing for the the 1st invite, the transport sends the response to the UA. 7. Now the UA behaves as though the 200OK is received for the re-invite!!!!! How to differentiate b/w 200 OK for INVITE or re-INVITE???. What should be the behavior of the UA for handling of this response. Pls Correct if i am wrong.... RFC3261 Snippet: Note that a UAC MUST NOT initiate a new INVITE transaction within a dialog while another INVITE transaction is in progress in either direction. 1. If there is an ongoing INVITE client transaction, the TU MUST wait until the transaction reaches the completed or terminated state before initiating the new INVITE. Regards, Zabi _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors "DISCLAIMER: This message is proprietary to Aricent and is intended solely for the use of the individual to whom it is addressed. It may contain privileged or confidential information and should not be circulated or used for any purpose other than for what it is intended. If you have received this message in error, please notify the originator immediately. If you are not the intended recipient, you are notified that you are strictly prohibited from using, copying, altering, or disclosing the contents of this message. Aricent accepts no responsibility for loss or damage arising from the use of the information transmitted by this email including damage from virus." _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
