Hi Vikram, Yes, we can send Re-Invite with no SDP offer, UAS can send this type of Re-Invite to know the session parameter of the existing dialog.
In case of B2BUA, I guess we should include all existing media stream in Re-Invite's offer (m= lines) and specify the one which we want to modify. Thanks, Dinesh -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Vikram Chhibber Sent: Wednesday, September 12, 2007 12:40 PM To: [email protected] Subject: [Sip-implementors] A question about SIP offer answer Hi, i have few queries on SIP offer/answer for which I couldn't find a straightforward answers: 1. We all are aware that we should be prepared to receive initial INVITE with no offer. In this case, the UAS is supposed to send its offer in the 200 Ok response. Is sending re-INVITE with no SDP valid case? I know sending UPDATE with no SDP is valid. 2. Once a unicast session is established, can any of the party send a new offer with entirely new "o" line?. The motivation for asking this question is that suppose I have a B2BUA who doesn't do much on SDP part and simply copies SDP from incoming messages to the outgoing messages. Now if this B2BUA wants to send re-INVITE (for hold or inactive media) to either party, does it needs to remember previous SDP negiotiation and modifies that SDP to send re-INVITE or can it create a SDP without considering anything form previous offer/answer. Thanks, ~Vikram _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments. WARNING: Computer viruses can be transmitted via email. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email. www.wipro.com _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
