Hi, >Yes. As Paul's conclusion of BCP, UAS should not include SDP after sending the ANSWER. > >My talking is , even UAS violate the BCP suggestion, there's no normative problem. Exactly. So, the important thing is to make clear, that IF the UAS sends SDP after sending the answer, it CAN NOT send a new offer. Personally I have never seen any problems caused if there is SDPs in additional responses - since most applications will ignore them. The problem is when someone claims that the SDP can't be ignored, because it contains a new offer. And, again, THAT is what we need to clarify: the UAS cannot send a new offer. Regards, Christer Christer Holmberg <christer.holmberg@xxxxxxxxxxxx> 2010-04-21 19:44 收件人 "gao.yang2@xxxxxxxxxx" <gao.yang2@xxxxxxxxxx> 抄送 OKUMURA Shinji <shinji.okumura@xxxxxxxxxxxx>, "sipping@xxxxxxxx" <sipping@xxxxxxxx>, "sipping-bounces@xxxxxxxx" <sipping-bounces@xxxxxxxx> 主题 RE: [Sipping] Is SDP in an unreliable response "the answer" ??? Hi, >> I don't disagree with what people are saying, but trying to read it >> from a I-am-a-new-implementor-and-I-would-like-to-get-it-right-from- >> the-beginning perspective I don't think anything is clarified. Eg. >> talking about that an SDP sent after the answer would be >> "missunderstood as a new offer" is confusing. > > I guess "missunderstood as a new offer" issue is clear: > If the session-id of o= line is the same the ANSWER, UAC can treate it as just COPY of the answer; > If the session-id is higher than the ANSWER's session-id, the UAC can treate it as *new* offer. As the UAC MUST ignore any SDP after ANSWER, it is OK for UAC doing nothing. But if UAC checks the SDP and find it is > *new* offer and violation of O/A rules then terminate the session, I also think it is also OK(UAS do bad behavior at first). I am not talking about the UAC procedure. I fully support saying that the UAC ignores the SDP. My problem is to say that the UAS shall not include SDP, because the UAC could "missunderstand it as a new offer". All we need to say is that the UAS MUST NOT include a new SDP. Regards, Christer > > -----Original Message----- > > From: sipping-bounces@xxxxxxxx > > [mailto:sipping-bounces@xxxxxxxx] On Behalf Of OKUMURA Shinji > > Sent: 21. huhtikuuta 2010 8:45 > > To: sipping@xxxxxxxx > > Subject: Re: [Sipping] Is SDP in an unreliable response "the > > answer" ??? > > > > Hi, > > > > Hans Erik van Elburg <ietf.hanserik@xxxxxxxxx> Tue, 20 Apr > > 2010 21:53:17 +0200 > > >On Tue, Apr 20, 2010 at 3:47 PM, Paul Kyzivat > > <pkyzivat@xxxxxxxxx> wrote: > > >> Here is my attempt at summarizing the discussion conclusions: > > >> > > >> Normative things (stated or implied in existing RFCs): > > >> > > >> - If the UAC sent an offer in the INVITE, then after it > > receives SDP > > >> (the > > >> answer) in a reliable response to the INVITE, any SDP in > > subsequent > > >> responses to the INVITE MUST be ignored. > > >> > > >> - Further, if SDP is received in an unreliable response to > > the invite > > >> prior to receiving SDP in a reliable response, then it MUST be > > >> treated as the answer for purposes of media processing, > > but not for > > >> purposes of determining when another offer may be sent or received. > > >> > > >[HE] I miss what the UAC should do in this case for subsequent > > >responses, does the following hold as well: > > >"If the UAC sent an offer in the INVITE, then after it receives SDP > > >(the answer) in an unreliable response to the INVITE, any SDP in > > >subsequent responses to the INVITE MUST be ignored/granted/... ." ? > > > > I agree. And it's certainly "ignored". > > > > >Regardless what the correct behaviour is, it is missing in > > your summary. > > > > > >> - if the UAS receives an offer in the INVITE, it MUST NOT > > include SDP > > >> in any response it sends until it has determined the > > intended answer > > >> SDP to the offer. > > >> > > >> - once the intended answer SDP is determined, it MUST be sent in a > > >> reliable response to the INVITE. It MAY be sent in one or more > > >> *preceding* unreliable provisional responses. > > >> > > >> Non-normative, best practice suggestions: > > >> > > >> - if the UAS receives an offer in the invite, once it has sent the > > >> answer in a reliable response, it should not send any SDP in > > >> subsequent responses to the INVITE. > > _______________________________________________ > > Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping > > This list is for NEW development of the application of SIP > > Use sip-implementors@xxxxxxxxxxxxxxx for questions on current > > sip Use sip@xxxxxxxx for new developments of core SIP > > > _______________________________________________ > Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping > This list is for NEW development of the application of SIP > Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip > Use sip@xxxxxxxx for new developments of core SIP > -------------------------------------------------------- ZTE Information Security Notice: The information contained in this mail is solely property of the sender's organization. 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This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the originator of the message. Any views expressed in this message are those of the individual sender. This message has been scanned for viruses and Spam by ZTE Anti-Spam system. _______________________________________________ Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping This list is for NEW development of the application of SIP Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip Use sip@xxxxxxxx for new developments of core SIP
