[MEDIACTRL] Question about draft-ietf-mediactrl-call-flows: Is "a=ctrl-package" OK?
worley@ariadne.com (Dale R. Worley) Thu, 09 May 2013 18:16 UTC
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Date: Thu, 09 May 2013 14:15:16 -0400
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Subject: [MEDIACTRL] Question about draft-ietf-mediactrl-call-flows: Is "a=ctrl-package" OK?
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[as chair] We're working on finishing up draft-ietf-mediactrl-call-flows and want to get the WG's input on an issue: Should the example call flows show uses of the "a=ctrl-package" attribute in the SDP? A typical example is in the SDP in the body of this INVITE to establish a CFW connection: To: <sip:MediaServer@ms.example.net:5060> From: <sip:ApplicationServer@as.example.com:5060>;tag=4354ec63 Call-ID: MDk2YTk1MDU3YmVkZjgzYTQwYmJlNjE5NTA4ZDQ1OGY. CSeq: 1 INVITE Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, UPDATE, REGISTER Content-Type: application/sdp Content-Length: 263 v=0 o=lminiero 2890844526 2890842807 IN IP4 as.example.com s=MediaCtrl c=IN IP4 as.example.com t=0 0 m=application 5757 TCP cfw a=connection:new a=setup:active a=cfw-id:5feb6486792a a=ctrl-package:msc-ivr/1.0 a=ctrl-package:msc-mixer/1.0 Historically, this attribute was defined in draft-boulton-mmusic-sdp-control-package-attribute, which was intended to proceed to standardization. But the effort to standardize "a=ctrl-package" has been abandoned and the last version of the draft expired in March 2012. But at least one vendor has implemented the attribute. Should we keep the "a=ctrl-package" attributes in the SDP examples? There are a lot of ways that you can look at this situation: - Devices that do not understand "a=ctrl-package" can safely ignore it, so examples containing it are upward-compatible with the standards (and probably with the real world). - The official examples should conform to the official standards. - If we intend to resume the standardization effort (respinning the draft), it is reasonable to presume its eventual success when writing examples. - If enough vendors implement it, it is a de-facto standard and should be shown. And then there's the problem that implementors don't properly distinguish between the specifications of the standard and the details of the examples. As was once stated vigorously, "The problem is people will code implementations to the call flows document, NOT the actual RFCs that define the protocols. Our choices are to take it out altogether or surround the section with lots of all-capital letters saying this may not be in the final specifications and is highly likely not to be the way it works in the wild." How should we handle this situation? Dale
- [MEDIACTRL] Question about draft-ietf-mediactrl-c… Dale R. Worley
- Re: [MEDIACTRL] Question about draft-ietf-mediact… Eric Burger
- Re: [MEDIACTRL] Question about draft-ietf-mediact… Tim Melanchuk
- Re: [MEDIACTRL] Question about draft-ietf-mediact… DRAGE, Keith (Keith)
- Re: [MEDIACTRL] Question about draft-ietf-mediact… Dale R. Worley
- Re: [MEDIACTRL] Question about draft-ietf-mediact… Eric Burger