Re: [MMUSIC] Eric Rescorla's No Objection on draft-ietf-mmusic-sdp-bundle-negotiation-51: (with COMMENT)

[Eric Rescorla <[e-mail]>]

On Wed, May 23, 2018 at 12:32 AM, Christer Holmberg <
[e-mail]> wrote:

> Hi,
>
> >>>>>>>   [Section 7.3.1] as the answerer tagged "m=" section.  In the
> answer
> >>>>>>>   the answerer BUNDLE-tag indicates the answerer tagged "m="
> section.
> >>>>>>>
> >>>>>>> I'm having trouble reading this paragraph. How do you select an m=
> section that correspond to the selected m= section.
> >>>>>>
> >>>>>> The n:th m- line in an answer corresponds to the n:th m- line in
> the offer.
> >>>>>>
> >>>>>> There was some discussion about the terminology, and “corresponds”
> was the outcome.
> >>>>>>
> >>>>>> I did find a small nit in the text, though:
> >>>>>>
> >>>>>> s/”section in that”/”section that”
> >>>>>
> >>>>> My point is that this paragraph just is too hard to read. My problem
> isn't corresponds, it's
> >>>>> "select" and "selected" together. Can you rewrite it so that it's
> clearer. Maybe just indicating
> >>>>> that one is is the offer and one is in the answer?
> >>>>
> >>>> What about:
> >>>>
> >>>>   The answerer MUST select the "m=" section *in the answer* that
> corresponds to the
> >>>>   selected offerer tagged "m=" section in the corresponding offer
> >>>>   [Section 7.3.1] as the answerer tagged "m=" section.  In the answer
> >>>>   the answerer BUNDLE-tag indicates the answerer tagged "m=" section.
> >>>
> >>> This seems clearer, but I'm not sure what "selected" is doing in
> "selected offerer tagged". Can you explain?
> >>
> >> The answerer first selects the offer tagged "m=" section, as described
> in section 7.3.1. After that, it selects
> >> the corresponding "m=" section in the answer as the answerer tagged
> "m=" section.
> >
> > Well, the use of "selected" here in both cases is super-confusing.
> >
> > I think what would be easiest would simply be to merge these two
> sections. I.e., the answerer determines (it actually doesn't "select")
> > the tagged m= section and then places it in its own answer.
>
> "Selected" is a terminology we spent quite a bit of time discussing back
> in the days, and it is used throughout the document.
>

And yet it's extremely confusing the way it is used here.


> But, below is a suggestion on to merge the sections, which hopefully will
> be more clear:
>
>
> 7.3.1.  Answerer Selection of tagged 'm=' sections
>
>    When the answerer selects the offerer tagged "m=" section, it first
>    checks the suggested offerer tagged "m=" section [Section 7.2.1].
>    The answerer MUST check whether the "m=" section fulfils the
>    following criteria:
>
>    o  The answerer will not move the "m=" section out of the BUNDLE
>       group [Section 7.3.3]; and
>
>    o  The answerer will not reject the "m=" section [Section 7.3.4]; and
>
>    o  The "m=" section does not contain a zero port value.
>
>    If all of the criteria above are fulfilled, the answerer MUST select
>    the "m=" section as the offerer tagged "m=" section. In addition, in
>    the corresponding answer, the answerer MUST select the "m=" section that
>    corresponds to the offerer tagged "m=" section as the answerer
>    tagged "m=" section. In the answer the answerer BUNDLE-tag indicates
> the
>    answerer tagged "m=" section.
>

This is still confusing. There's no difference between these two
"selections".

   If all of the criteria above are fulfilled, the answerer MUST select
   the "m=" section as the offerer tagged "m=" section, and MUST also mark
    the corresponding m= section as the tagged "m=" section in its
   answer.

-Ekr



>    If one or more of the criteria are not fulfilled, the answerer MUST
>    pick the next identification-tag in the identification-tag list in
>    the offer, and perform the same criteria check for the "m=" section
>    indicated by that identification-tag.  If there are no more
>    identification-tags in the identification-tag list, the answerer MUST
>    NOT create the BUNDLE group.  Unless the answerer rejects the whole
>    offer, the answerer MUST apply the answerer procedures for moving an
>    "m=" section out of a BUNDLE group [Section 7.3.3] or rejecting an
>    "m=" section within a BUNDLE group [Section 7.3.4] to every bundled
>    "m=" section in the offer when creating the answer.
>
>    [Section 17.1] shows an example of an offerer BUNDLE address:port
>    selection.
>
>    [Section 7.3.5] and [Section 17.1] show an example of an answerer
>    tagged "m=" section selection.
>
> Regards,
>
> Christer
>
>
>
>
>
>
>
>
>
>
>