[Council] 293

Philipp Hancke fippo at goodadvice.pages.de
Tue Apr 14 15:57:35 UTC 2015

hey Kev,

Am 14.04.2015 um 07:27 schrieb Kevin Smith:
> I’m -1 on 293 moving to Draft at the moment, as I can’t understand the normative requirement:
> "It MUST NOT change any parameter to conform the the negotiation defined in RFC 4585 Section 4. “

The RFC 4585 text this relates to is:
    The answerer
    MUST remove all attributes it does not understand as well as those it
    does not support in general or does not wish to use in this
    particular media session.  The answerer MUST NOT add feedback
    parameters to the media description and MUST NOT alter values of such

which basically is a complicated way of explaining that the responder 
must send an answer that is a subset of the offer.

We do not want to change those rules obviously.

> I suspect this is a simple change, but I’m not sure it’s purely editorial unless the meaning is clear to everyone except me.

How about changing the paragraph as follows (basically moving the 4585 
reference to the start).
To conform with the negotiation rules outlined in RFC 4585 Section 4, 
the responder MUST send any <rtcp-fb/> element as-is if it accepts it. 
It MUST NOT change any parameter. It MUST NOT add any <rtcp-fb/> element 
that was not offered by the initiator. It MUST NOT modify the 'value' of 
any <rtcp-fb-trr-int/> element. It can only remove the 
<rtcp-fb-trr-int/> element or reject the content. If all the feedback 
messages are removed but the responder wants to stay in the RTP/AVPF 
profile, it MUST put a <rtcp-fb-trr-int/> element with the same 'value' 
that it received from the intiator, if the initiator did not provide a 
<rtcp-fb-trr-int/> element, then this value is "0".

Alternatively, we can replace this paragaph with text that explain that 
the rules from 4585 still apply.

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