Thank for your response. As you correctly said the warning code 306 indicates that the recipient cannot understand one of the a= lines. But in this case recipient is understanding the a=rtpmap:100 UNACCEPTABLECODEC/8000 line. Only thing it is not understanding is the media format(i.e. encoding type). I think 306 is best suited for the case of a new attribute i.e a=useless. If you ask me i would still say that warning code 305 is best suited.
Thanks, On Thu, Mar 10, 2011 at 9:13 PM, Worley, Dale R (Dale) <dwor...@avaya.com>wrote: > ________________________________________ > If an initial INVITE from an endpoint offer contains the sdp as follows. > > m=audio 15190 RTP/AVP 100 101\r\n > a=fmtp:18 annexb=yes\r\n > a=fmtp:101 0-15\r\n > a=rtpmap:100 UNACCEPTABLECODEC/8000\r\n > a=sendrecv > > the terminating endpoint returns an error response 488 with a warning > header as follows. > > Warning: 306 132.177.120.67:5060 "Attribute not understood" > > Is 306 is correct response? > ________________________________________ > > The response is 488, which is correct if the recipient cannot find suitable > codecs in the SDP offer. > This makes sense, as the SDP contains no audio coded. > > The warning code 306 indicates that the recipient cannot understand one of > the a= lines. Unfortunately, > the message does not indicate which a= line it does not understand. My > understanding is that > if the interpreter of SDP does not understand an a= line, it should ignore > it, which is aligned with > the fact that the response contains a warning (as opposed to an error) > about not understanding an a= line. > > I also see that the m= line mentions codec 101, but there is no > a=rtpmap:101 line, which is I think technically > an error, but in practice means that the recipient must ignore codec 101. > > Dale > _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
