Subject: [clue] Aligning CLUE with draft-ietf-avtext-rtp-grouping-taxonomy

From: Paul Kyzivat <[email-masked]>
Date: Fri, 18 Jul 2014 19:22:19 -0400

The following are some terminology conflicts between CLUE and the the 
RTP Grouping Taxonomy draft:

* Media Capture is described in the taxonomy as follows:

    4.8. Media Capture

    Telepresence specifications from CLUE WG uses this term to describe
    either a Media Capture (Section 2.1.2) or a Media Source
    (Section 2.1.4), depending on in which context the term is used.

    2.1.2. Media Capture

    Media Capture is the process of transforming the Physical Stimulus
    (Section 2.1.1) into digital Media using an appropriate sensor or
    transducer.

    2.1.4. Media Source

    A Media Source is the logical source of a reference clock
    synchronized, time progressing, digital media stream, called a Source
    Stream (Section 2.1.5).  This transformation takes one or more Raw
    Streams (Section 2.1.3) and provides a Source Stream as output.  This
    output has been synchronized with some reference clock, even if just
    a system local wall clock.

The CLUE term Media Capture means *either* a Taxonomy Media Capture or a 
Taxonomy Media Source, depending on context.

Perhaps it is ok if it is the union of these two, *if* it is clear how 
they fit together and can be distinguished when need be. It would be 
better if our term meant only one of these things.

But either way, it is pretty unreasonable to use the *same* term 
differently in the two documents.

I think one of use must change. I don't care which one.

* The "Endpoint"/"End Point" is described in the taxonomy as follows:

    4.5. Endpoint

    Telepresence specifications from CLUE WG use this term to describe
    exactly one Participant (Section 2.2.3) and one or more End Points
    (Section 2.2.1).

    2.2.1. End Point

       Editor's note: Consider if a single word, "Endpoint", is
       preferable

    A single addressable entity sending or receiving RTP packets.  It may
    be decomposed into several functional blocks, but as long as it
    behaves as a single RTP stack entity it is classified as a single
    "End Point".

    2.2.3. Participant

    A Participant is an entity reachable by a single signaling address,
    and is thus related more to the signaling context than to the media
    context.

Technically there is no conflict here because "Endpoint" and "End Point" 
are different. But they are just different spelling, so easily confused 
that it presents a problem. Also, there is the note that the Taxonomy 
might want to change making them fully conflict.

Again I think one of use must change. I don't care which one.

* MCU is described in the taxonomy as follows:

    4.7. Multipoint Control Unit (MCU)

    This term is commonly used to describe the central node in any type
    of star topology [I-D.ietf-avtcore-rtp-topologies-update] conference.
    It describes a device that includes one Participant (Section 2.2.3)
    (usually corresponding to a so-called conference focus) and one or
    more related End Points (Section 2.2.1) (sometimes one or more per
    conference participant).

This is a quite good definition for CLUE purposes, except that this 
definition does not assume CLUE support, while when we use MCU in CLUE 
we mean something that is an MCU in the sense defined here *and* also is 
a CLUE-Capable device as defined in the CLUE signaling draft.

I think for this we should update the CLUE docs to use "CLUE MCU" 
instead of just "MCU", and then define that with reference to this 
definition.

I'm hoping Jonathan can serve as a proxy for the taxonomy author team. 
For now I'm only sending this to clue, not mmusic.

	Thanks,
	Paul

---

From: Christian Groves <[email-masked]>
Date: Mon, 21 Jul 2014 14:57:41 +1000

Hello Paul,

Please see below.

Regards, Christian

On 19/07/2014 9:22 AM, Paul Kyzivat wrote:
> The CLUE term Media Capture means *either* a Taxonomy Media Capture or 
> a Taxonomy Media Source, depending on context.
>
[CNG] I think the descriptions are correct. The "CLUE media capture" may 
be either a media capture or media source as described. Perhaps it can 
be easily fixed by calling cl.4.8 "CLUE Media Capture".
> Technically there is no conflict here because "Endpoint" and "End 
> Point" are different. But they are just different spelling, so easily 
> confused that it presents a problem. Also, there is the note that the 
> Taxonomy might want to change making them fully conflict.
>
[CNG] Again is it simply the case of pre-fixing 4.5 with "CLUE"?
> we mean something that is an MCU in the sense defined here *and* also 
> is a CLUE-Capable device as defined in the CLUE signaling draft.
>
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