Thanks for the reference Aneesh ..very helpful --- On Thu, 2/25/10, Aneesh Naik <[email protected]> wrote:
From: Aneesh Naik <[email protected]> Subject: Re: [Sip-implementors] SIP Media Flow Attribute question To: "Rashid Shakil" <[email protected]> Cc: "Brett Tate" <[email protected]>, "[email protected]" <[email protected]> Date: Thursday, February 25, 2010, 10:50 PM Hi Rashid, Yes, UAC can receive media packets the other side. These are early media. RFC 3960 explains clearly how early media and regular media needs to be handled by UAs: Answer to your question: <<Is this acceptable, can they send media stream without sharing SDP ? Later on they send 18x with SDP and that's when media stream flowing in both direction.> Section: 3.1.Following normal SIP procedures, the UAC is ready to play any incoming media as soon as it sends the initial offer in the INVITE. The UAS sends the answer in a reliable provisional response and can send media as soon as there is media to send. Even if the first media packets arrive at the UAC before the 1xx response, the UAC will play them. Section 3.3. SIP signalling traverses a different path than the media. The media path is typically optimized to reduce the end-to-end delay (e.g., minimum number of intermediaries), while the SIP signalling path typically traverses a number of proxies providing different services for the session. Hence, it is very likely that the media packets with early media reach the UAC before any SIP message that could contain an early media indicator. Thanks, Aneesh Read more: http://www.faqs.org/rfcs/rfc3960.html#ixzz0gbtht0Xl Read more: http://www.faqs.org/rfcs/rfc3960.html#ixzz0gbsVySMn On Thu, Feb 25, 2010 at 10:46 PM, harneet billing <[email protected]> wrote: Rashid, Since the UAC has already advertised the codec and ports where it's willing to accept the media on, the UAS can start the RTP stream after receiving this info in the INVITE sent by the UAC. This would be the Early Media. Regards, Harneet On Thu, Feb 25, 2010 at 10:24 PM, Rashid Shakil <[email protected]>wrote: > > Brett, > > Thanks for the reference and prompt response. My SIP peer is sending RTP \ > media right after sending 100 TRYING means ... > > INVITE Sent from UA ====== > > 100 TRYING received from SIP peer < ========= > RTP started from SIP Peer (one direction) <====== > > Is this acceptable, can they send media stream without sharing SDP ? Later > on they send 18x with SDP and that's when media stream flowing in both > direction. > > - Rashid Shakil > > > --- On Thu, 2/25/10, Brett Tate <[email protected]> wrote: > > From: Brett Tate <[email protected]> > Subject: RE: [Sip-implementors] SIP Media Flow Attribute question > To: "Rashid Shakil" <[email protected]>, " > [email protected]" < > [email protected]> > Date: Thursday, February 25, 2010, 11:45 AM > > > If a SIP UA sends an INVITE without specifiying the > > media flow direction attributes (sendrecv, recvonly, sendonly, and > > inactive). What is the default behavior for the receiving gateway in > > setting up media flow ? > > RFC 4566 snippet: "If none of the attributes "sendonly", "recvonly", > "inactive", and "sendrecv" is present, "sendrecv" SHOULD be assumed as the > default for sessions that are not of the conference type "broadcast" or > "H332" (see below)." > > > > > > _______________________________________________ > Sip-implementors mailing list > [email protected] > https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors > -- Doubts are better off clarified, than their explanations assumed. _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
