Re: [sipcore] AD review draft-ietf-sipcore-199-00 - offer/answer

["Christer Holmberg" <[e-mail]>]

 
Hi,

>>In Sections 5 and 9, the document says to include SDP in a 199 if
>>RFC3263 requires it. I would like to see some additional discussion
>>around whether this is the right way to deal with
>>this edge case. If it is, then this document needs to explain how a 
>>UA should handle receiving an offer in a 199.  A
>>different path out is to say that such a 199 MUST NOT be sent 
>>reliably.
>>(More explanation of why we allow 199 to be sent
>>reliably at all (why this is SHOULD not MUST) would also help).
>>
>>I wouldn't like to generally disallow to send 199 reliably, in case 
>>there is some future use-case which would need it. That's the reason 
>>for the SHOULD: don't send it reliably unless you have a good reason 
>>to do so.
>>
>>Regarding the specific must-include-SDP-offer case (which will be very

>>rare, in my opinion) I see two alternatives:
>>
>>1.  We disallow reliable 199 in such cases 2.  We say that the UAS 
>>must include e.g. an SDP offer without any m- lines.
>>
>>My proposal is to describe both alternatives, and say that the UAS 
>>MUST use of them.
>
>
>I'm not seeing any changes in -01 addressing this comment?

I changed and extended (will be seen in -02) the note into normative
text:

"A 199 Early Dialog Terminated provisional response SHOULD NOT contain
an SDP offer/answer message body, unless required by the rules in
[RFC3264].

If the INVITE request did not contain an SDP offer, and the 199
response is the first reliably sent response, the 199 response is
required to contain an SDP offer. In this case the UAS SHOULD send
the 199 response unreliable, or include an SDP offer with no m- lines 
in the reliable 199 response."

Regards,

Christer