Hi, >>>Before sending an answer, >>>- An UAS MAY send unreliable provisional responses with a SDP. >>>- And the SDP MUST be identical to an answer SDP. >>> >>>After sending an answer, >>>- The UAS should not insert a SDP in any response. >>> >>>Is this OK? >> >>That text still doesn't say what an SDP inserted after sending the >>answer means, only that it should not be sent. > >The SDP means nothing. it is neither an offer nor an answer. Exactly. In my opinion that is what is important - not whether the UAS inserts SDP or not. >>I still don't see why we need to make a separation about SDP sent >>before and after the answer, because in both cases the SDP must be >>identical to the answer. > > 1. RFC3261 says that UAS MAY send it before the answer and > doesn't say nothing after the answer. That is one reason why we are writing the draft - to clarify things which may not be clear in the specs. >2. The SDP MUST be ignored by UAC. it is meaningless. I agree, and that is what we must be clear about. Because, as we know, some people want to send a NEW offer (or updated answer) in a subsequent response, and that is not allowed. >3. if another o/a exchange is occured (using UPDATE or PRACK), it is not even a confirmation. > >And, again, I know there are many implementations that send >a copy of the SDP after the SDP answer has been sent, so instead of >saying that it should not be done I think it is much more important to >say that, if it is done, it must be identical to the SDP answer. In other >words, to make it clear that the UAS can not send a NEW offer (or >updated answer) in a subsequent response after the SDP answer has been sent. > >Since UAC MUST ignored it, there is no problem on a interworking. >Why must it be identical to the SDP answer? Well, if you look at it that way, fine. But, then the important thing is that the UAC must ignore it - not that the UAS should not send it. Regards, Christer > >Regards, > > > >Christer > > > >Hans Erik van Elburg <ietf.hanserik@xxxxxxxxx> Mon, 19 Apr 2010 > >13:55:41 +0200 > >>> - An UAS MAY insert a SDP body that is identical to the > SDP answer, > >>> in an unreliable provisional response before the SDP answer has > >>> been sent. > >>> > >>> - The UAS MUST NOT insert a SDP body that is not > identical to the > >>> SDP answer, in an unreliable provisional response before the SDP > >>> answer has been sent. > >>> > >>This is terribly confusing. Very probabe that noone will > get it right. > >>Triple negation. And talking about sending and answer before the > >>answer has been sent. ??? > >> > >> > >>> - The UAS MUST NOT insert a SDP body in any response > after the SDP > >>> answer has been sent. > >>> > >>This means that you can't send it again after you've send it in an > >>unreliable provisional response. Do you want tto say that? > >> > >>/Hans Erik van Elburg > _______________________________________________ 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
