On Thu, Nov 20, 2008 at 9:49 AM, Paul Kyzivat <[EMAIL PROTECTED]> wrote:
> > > NC Reddy wrote: > >> I agreed it breaks the SDP offer/answer protocol, but i think it won't >> break SIP controlling protocol rules. >> > > The sip controlling protocol rules require that the o/a be completed. > > The context of the scenario is: >> UAC(user) <---------->AS (Announcement Sever) >> AS needs to know the RTP IP/port of UAC for to send some announcement >> traffic. The RTP traffic is "one way" i.e from AS to UAC. So in the above >> context, what's the purpose of sending SDP information (i.e RTP IP and port >> ) of AS to UAC?. I can see only to compliant for full fill the offer/answer >> model. >> > > In that case, the AS may respond with an answer containing the appropriate > m-line, with a=sendonly. The answer provides the necessary data for the > exchange of RTCP. Also it is increasingly common for UAs (or something in > their network) to require the media to be symmetric, using the address in > the answer as a gate for what will be accepted. > > So why would you not want to send the answer? It costs almost nothing extra > in signaling. The requirement is that AS needs to play announcement to the UAC and terminate the call (i.e 2xx/non-2xx) with UAC on given call context. For AS to play announcement to User, does it possible AS can play announcement on UAC RTP IP and Port before sending final resposnses(i.e 2xx or non-2xx responses)? without sending announcement server sdp answer. For to emulate one way announcement traffic, does SDP answer from AS should have "valid" RTCP ports towards User(UAC)?, can't AS can send some dummy answer to UAC to full fill the sdp offer/answer. > > > Thanks, > Paul > > Thanks in advance. >> Regards >> Channa >> >> On Wed, Nov 19, 2008 at 7:46 PM, Paul Kyzivat <[EMAIL PROTECTED]<mailto: >> [EMAIL PROTECTED]>> wrote: >> >> No this isn't valid. The offer must be answered. >> >> This is the Session Initiation Protocol. Without an answer you have >> not initiated a session. >> >> Paul >> >> NC Reddy wrote: >> >> Hi, >> I have the following context question: >> >> UAC <------------->AS(B2BUA) >> | ------F1 (INVITE)---> >> * SDP-Offer* >> >> <-----F2: 100 Trying--- >> >> <----F3: 200 OK*(NO-SDP)*---- //Does this step >> is valid >> without SDP, ?: >> >> ------F4:ACK------------> >> >> Questions: >> >> - Does the 200 OK response without SDP -Answer is a "valid" >> sip response >> in the above context?. >> - If not what are the reason(s)? >> >> Regards >> Channa >> _______________________________________________ >> Sip-implementors mailing list >> Sip-implementors@lists.cs.columbia.edu >> <mailto:Sip-implementors@lists.cs.columbia.edu> >> https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors >> >> >> _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
