Re: [MMUSIC] Bundle and "m=" line terminology [Re: Review of draft-ietf-mmusic-sdp-bundle-negotiation-32 (Part I)]

[Eric Rescorla <[e-mail]>]

On Thu, Nov 3, 2016 at 8:31 PM, Flemming Andreasen <[e-mail]>
wrote:

>
> Christer reminded me to pick up the part below:
>
>
> On 10/3/16 10:00 AM, Eric Rescorla wrote:
>
>
>
> On Mon, Oct 3, 2016 at 4:01 AM, Christer Holmberg <
> [e-mail]> wrote:
>
> <snip>
>
> >S 10.3.1.1.
>>>
>>> >   When an offerer generates an initial offer, the offerer MUST
>>>
>>> >   associate either an SDP 'rtcp-mux' attribute [RFC5761] or an SDP
>>>
>>> >   'rtcp-mux-only' attribute [I-D.ietf-mmusic-mux-exclusive] with each
>>>
>>> >   bundled RTP-based "m=" line in the offer.  The offerer MUST associate
>>>
>>> >   an SDP 'rtcp-mux-only' attribute with each bundle-only "m=" line.  If
>>>
>>> >   the offerer associates a 'rtcp-mux-only' attribute with an "m=" line,
>>>
>>> >   the offerer may also associate a 'rtcp-mux' attribute with the same
>>>
>>> >   "m=" line, as described in [I-D.ietf-mmusic-mux-exclusive].
>>>
>>> >
>>>
>>> > This is a particularly egregious case of associate disease that could
>>>
>>> > be easily solved by using "add" when referring to the attributes
>>>
>>> > you put in the m= section.
>>>
>>>
>>>
>>> People have previously said that you don’t “add” attributes to m- lines:
>>> you add port values etc, but not attributes.
>>>
>>>
>>>
>>> This is an example of where I’ve had to re-write big parts of the
>>> documents a number of times already, because every time someone else reads
>>> the document he/she is not happy with the terminology. I just don’t want to
>>> do it again.
>>>
>>
>> The terminology that JSEP uses is that "m= sections" include attribute
>> lines.
>>
>> I think this is a lot clearer.
>>
>>  I don’t personally disagree, but there are people that have had other
>> opinions.
>>
>>  In general I think it would be really useful to have common terminology
>> in BUNDLE and JSEP, but I don’t want to re-write the document once again,
>> and then later be told to do it again…
>>
>
> Resolving the appropriate terminology seems like a chair issue.
>
> RFC 4566 (SDP) Section 5 makes it pretty clear that a Media Description
> consists of an "m=" line optionally followed by a number of other lines
> (typically attribute lines). In other words, an "m=" line and a media
> description is generally not synonymous.
>
> Earlier versions of bundle did not reflect that distinction properly, and
> about a year ago, I asked for the terminology to be aligned with RFC 4566.
> There were a few off-list comments from other people that agreed with that
> view and the draft got updated accordingly (as of -24). That is what the
> current bundle draft does and I continue to believe that is what it should
> do.
>

This message leaves me extremely puzzled because I'm not saying otherwise,
and that's why JSEP uses "m= section" for this concept. Media description
would also be fine. What is problematic is the use of "associated with an
m= line" to mean "part of a media description" or "part of an m= section".
That text is extremely confusing, especially when the word "associated" is
used in a number of other concepts. So, what I'm asking for is one of the
alternative terms I list here.

-Ekr


> Thanks
>
> -- Flemming (with chair hat on)
>
>
>
> -Ekr
>
>
>> Regards,
>>
>> Christer
>>
>>
>>
>
>
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