Hi Please refer RFC 4028 Section 7.4. Generating Subsequent Session Refresh Requests
==== It is RECOMMENDED that the UPDATE request not contain an offer [4], but a re-INVITE SHOULD contain one, even if the details of the session have not changed. In that case, the offer MUST indicate that it has not changed. In the case of SDP, this is accomplished by including the same value for the origin field as did previous SDP messages to its peer. The same is true for an answer exchanged as a result of a session refresh request; if it has not changed, that MUST be indicated. ==== Regards Tarun Gupta -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Manolis Katsidoniotis Sent: Thursday, January 08, 2015 11:46 AM To: Roman Shpount Cc: sip-implementors Subject: Re: [Sip-implementors] Do I need SDP in order to refresh an already established offer/answer session? thanks Roman do you by any chance happen to roughly remember the rfc section that specifies that requirement? thanks again Manolis On Wed, Jan 7, 2015 at 5:49 PM, Roman Shpount <[email protected]> wrote: > On Wed, Jan 7, 2015 at 6:14 PM, Manolis Katsidoniotis > <[email protected]> > wrote: > >> I have an IMS scenario where offer/answer is complete, users are in >> talking state using one simple audio stream. >> >> (Much sooner than) half the session time, B side client is attempting >> to refresh the session using re-INVITE without SDP. >> A acknowledges the refresh with 200OK without SDP >> >> As far as I know this is not an error as session refresh does not >> require SDP,, however it is rejected by the servers with cause >> invalid offer/answer. >> >> Should I include the SDP nonetheless and keep the same session id & >> version in the origin header? >> > > INVITE transaction without SDP in either INVITE or 200 OK is invalid. SDP > should always be present in INVITE success response (either answer if SDP > offer was sent in the INVITE or offer if no SDP was sent in the INVITE). > > One option is to send INVITE with the same SDP, which ideally should get > you the same SDP in response, but you should be prepared for a different > SDP as well. The better option is to do a session refresh using an UPDATE > request without SDP. > _____________ > Roman Shpount > > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/mailman/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/mailman/listinfo/sip-implementors
