Re: [MMUSIC] Questions about ICE candidates with BUNDLE - suggested text

[Christer Holmberg <[e-mail]>]

Hi Paul,

I am trying to follow the same style as BUNDLE in general. Yes, I know it's messy, and I've lost count of the number of times I've had to re-write everything, but I am not going to do it again. 

Now, I did put together the new ICE text rather quickly, so there may be some mistakes, though.

Regards,

Christer

-----Original Message-----
From: Paul Kyzivat [mailto:[e-mail]] 
Sent: 22 February 2016 22:14
To: Roman Shpount <[e-mail]>; Christer Holmberg <[e-mail]>
Cc: [e-mail]; Peter Thatcher <[e-mail]>; Ari Keränen <[e-mail]>
Subject: Re: [MMUSIC] Questions about ICE candidates with BUNDLE - suggested text

Christer,

[I'm replying to Christer, not Roman. For some reason I can't find Christer's original message in my email.]

This generally seems good to me. I noticed one thing:

While I understand the intent, you are using "associate", "associates" 
or "associated" in multiple ways, that may be confusing to some readers. 
E.g.:

    o  Among bundled "m=" lines with which the offerer has associated a
       shared address, the offerer only associates ICE-related media-
       level SDP attributes with the "m=" line associated with the
       offerer BUNDLE-tag.
...
    NOTE: The bundle-only "m=" line, if accepted by the answerer, will
    inherit the candidates associated with the selected offerer BUNDLE
    address.  An answerer that does not support BUNDLE would not accept a
    bundle-only "m=" line.
...
    When an offerer or answerer associates a shared address (i.e. a
    previously selected BUNDLE address) with one or more bundled "m="
    lines, the offerer (or answerer) MUST only associate SDP 'candidate'
    attributes with the "m=" line associated with the offerer BUNDLE-tag
    (or the answerer BUNDLE-tag) address).  The offerer or answerer MUST
    NOT associate 'candidiate' attributes with any other bundled "m="
    line to which the offerer (or answerer) associates a shared address.
...
    When an offerer receives an answer, if the answerer supports and uses
    the ICE mechanism and the BUNDLE extension, the offerer MUST
    associate the same ICE candidates, associated with the "m=" line
    representing the offerer BUNDLE address (selected by the answerer),
    with each bundled "m=" line.

So, which one of these things is not like the others? (This is a game we play with kids. Do they do it in Sweden too?)

In most cases this is talking about where you put things in the SDP. But the last one above isn't that - it is about the implementation taking data from the answer and using it to update internal data structures.

I don't have a specific suggestion for improving it. But I think it would be good to use someting other that "associate" in this case. I
*think* it is the only place where it is used this way.

	Thanks,
	Paul


On 2/22/16 2:29 PM, Roman Shpount wrote:
> On Mon, Feb 22, 2016 at 5:10 AM, Christer Holmberg 
> <[e-mail] 
> <mailto:[e-mail]>>
> wrote:
>
>     Assuming we will only associated ICE candidates to the “m=” line
>     associated with the offerer/answerer BUNDLE-tag, below is a first
>     suggested of modified ‘ICE Considerations’ text:
>
>     __ __
>
>     -----------------------____
>
>     __ __
>
>     11.  ICE Considerations____
>
>     __ __
>
>     11.1.  General____
>
>     __ __
>
>         This section describes how to use the BUNDLE grouping 
> extension____
>
>         together with the Interactive Connectivity Establishment 
> (ICE)____
>
>         mechanism [RFC5245].____
>
>     __ __
>
>         The generic procedures for negotiating usage of ICE using 
> SDP,____
>
>         defined in [I-D.ietf-mmusic-ice-sip-sdp], also apply to usage of
>     ICE____
>
>         with BUNDLE, with the following exceptions:____
>
>     __ __
>
>         o  When BUNDLE addresses for a BUNDLE group have been selected
>     for____
>
>            both endpoints, ICE connectivity checks and keep-alives only
>     need____
>
>            to be performed for the whole BUNDLE group, instead of per
>     bundled____
>
>            "m=" line.____
>
>     __ __
>
>         o  Among bundled "m=" lines with which the offerer has
>     associated a____
>
>            shared address, the offerer only associates ICE-related
>     media-____
>
>            level SDP attributes with the "m=" line associated with 
> the____
>
>            offerer BUNDLE-tag.____
>
>     __ __
>
>         o  Among bundled "m=" lines with which the answerer has
>     associated a____
>
>            shared address, the answerer only associates ICE-related
>     media-____
>
>            level SDP attributes with the "m=" line associated with 
> the____
>
>            answerer BUNDLE-tag.____
>
>     __ __
>
>         Support and usage of ICE mechanism together with the BUNDLE
>     extension____
>
>         is OPTIONAL.____
>
>     __ __
>
>     11.2.  SDP Offer/Answer Procedures____
>
>     __ __
>
>     11.2.1.  General____
>
>     __ __
>
>         When an offerer associates a unique address with a bundled "m="
>     line____
>
>         (excluding any bundle-only "m=" line), it MUST also associate
>     unique____
>
>         ICE candidates to the "m=" line, according to the procedures 
> in____
>
>         [I-D.ietf-mmusic-ice-sip-sdp].____
>
>     __ __
>
>         An offerer MUST NOT associate ICE candidates with a bundle-only
>     "m="____
>
>         line with a zero port value.____
>
>     __ __
>
>         NOTE: The bundle-only "m=" line, if accepted by the answerer,
>     will____
>
>         inherit the candidates associated with the selected offerer
>     BUNDLE____
>
>         address.  An answerer that does not support BUNDLE would not
>     accept a____
>
>         bundle-only "m=" line.____
>
>     __ __
>
>         When an offerer or answerer associates a shared address (i.e. 
> a____
>
>         previously selected BUNDLE address) with one or more bundled
>     "m="____
>
>         lines, the offerer (or answerer) MUST only associate SDP
>     'candidate'____
>
>         attributes with the "m=" line associated with the offerer
>     BUNDLE-tag____
>
>         (or the answerer BUNDLE-tag) address).  The offerer or answerer
>     MUST____
>
>         NOT associate 'candidiate' attributes with any other bundled
>     "m="____
>
>         line to which the offerer (or answerer) associates a shared
>     address.____
>
>         This also apply to any other ICE-related media-level SDP
>     attribute.____
>
>     __ __
>
>         NOTE: The following ICE-related media-level SDP attributes 
> are____
>
>         defined in [I-D.ietf-mmusic-ice-sip-sdp]: 'candidiate', 
> 'remote-____
>
>         candidates', 'ice-mismatch', 'ice-ufrag', 'ice-pwd', and 
> 'ice-____
>
>         pacing'.____
>
>     __ __
>
>     11.2.2.  Generating the Initial SDP Offer____
>
>     __ __
>
>         When an offerer generates an initial offer, it associates unique
>     ICE____
>
>         candidates with the bundled "m=" lines, according to Section
>     11.2.1.____
>
>     __ __
>
>     11.2.3.  Generating the SDP Answer____
>
>     __ __
>
>         When an answerer generates an answer that contains a BUNDLE
>     group,____
>
>         the answerer MUST only associate SDP 'candidate' attributes 
> (and____
>
>         other ICE-related media-level SDP attributes) with the "m=" 
> line____
>
>         associated with the answerer BUNDLE-tag.____
>
>     __ __
>
>     11.2.4.  Offerer Processing of the SDP Answer____
>
>     __ __
>
>         When an offerer receives an answer, if the answerer supports and
>     uses____
>
>         the ICE mechanism and the BUNDLE extension, the offerer 
> MUST____
>
>         associate the same ICE candidates, associated with the "m=" 
> line____
>
>         representing the offerer BUNDLE address (selected by the
>     answerer),____
>
>         with each bundled "m=" line.____
>
>     __ __
>
>     11.2.5.  Modifying the Session____
>
>     __ __
>
>         When an offerer generates a subsequent offer, it associates
>     unique or____
>
>         shared ICE candidates with the bundled "m=" lines, according 
> to____
>
>         (Section 11.2.1).____
>
>
>
> I am not 100% sure about what exactly is meant by ICE candidate being 
> associated with an m= line. Does this mean ICE candidate is created 
> for this m= line and "candidate" SDP attribute is included in this m= line?
>
> Overall the text is good, but I would explicitly replace "ICE 
> candidates" with "ICE candidates or any other ICE-related media-level 
> SDP attributes" to avoid any potential confusion. This will also make 
> the phrase "This also apply to any other ICE-related media-level SDP 
> attribute" unnecessary.
> _____________
> Roman Shpount