Re: [Mops] Comments on draft-ietf-mops-streaming-opcons-07

[Spencer Dawkins at IETF <[e-mail]>]

Dear Chairs (and, of course, co-editors),

On Fri, Dec 10, 2021 at 1:05 PM Mike English <[e-mail]> wrote:

> Hello MOPS!
>
> I finally carved out some time this morning to re-read the draft
> "Operational Considerations for Streaming Media" with fresh eyes.
>
> One thing that struck me on this read through is: the purpose of the
> document is not very clearly defined. The lack of a clearly defined
> purpose makes it difficult to evaluate whether the document succeeds
> at its stated goals. I think it would be good to clarify this before
> proceeding beyond the working group.
>
> Here's what we have at the end of the introduction now:
>
>    This document examines networking issues as they relate to quality of
>    experience in internet video delivery.  The focus is on capturing
>    characteristics of video delivery that have surprised network
>    designers or transport experts without specific video expertise,
>    since these highlight key differences between common assumptions in
>    existing networking documents and observations of video delivery
>    issues in practice.
> <
> https://www.ietf.org/archive/id/draft-ietf-mops-streaming-opcons-07.html#section-1-8
> >
>
>    Making specific recommendations on operational practices aimed at
>    mitigating these issues is out of scope, though some existing
>    mitigations are mentioned in passing.  The intent is to provide a
>    point of reference for future solution proposals to use in describing
>    how new technologies address or avoid these existing observed
>    problems.
> <
> https://www.ietf.org/archive/id/draft-ietf-mops-streaming-opcons-07.html#section-1-9
> >
>
> It seems like the document currently falls somewhere between a
> description of current best practices and a set of problem statements
> that could theoretically justify new protocol work within IETF, but
> there's quite a bit of ambiguity remaining.
>
> Another interpretation could be that this document intends to
> primarily serve as a useful reference document for shared
> terminology. In fact, the document does provide a definition for
> "streaming" as well as definitions for several classes of latency.
> Which brings me to my second observation: upon re-reading, the latency
> categories defined by this draft seem somewhat arbitrary.
>
> (See: "3. Latency Considerations")
> <
> https://www.ietf.org/archive/id/draft-ietf-mops-streaming-opcons-07.html#name-latency-considerations
> >
>
> If the intent is for this document to serve as a source for a shared
> vocabulary, I wonder if we could try to ground these categories a bit
> more firmly on specific qualitative differences between the different
> categories. Either by reorienting around use cases or by seeking out
> some specific latency thresholds, e.g. in human computer interaction
> research.
>
> Finally, I noticed that there are some passing references to real-time
> communication in the document which imply but do not explicitly state
> that real-time communication applications are considered outside of
> the scope of the document. However, by the provided definition of
> "streaming" it's hard to see how real-time communications applications
> would not qualify:
>    This document specifically focuses on the streaming applications and
>    defines streaming as follows:
>    *  Streaming is transmission of a continuous media from a server to a
>       client and its simultaneous consumption by the client.
>    *  Here, continuous media refers to media and associated streams such
>       as video, audio, metadata, etc.  In this definition, the critical
>       term is "simultaneous", as it is not considered streaming if one
>       downloads a video file and plays it after the download is
>       completed, which would be called download-and-play.
>
> I think this document contains many useful concepts and explanations
> relevant to IETF work exploring the development of new protocols or
> protocol extensions, however, in my opinion, it suffers from a lack of
> clarity of purpose, and I think that needs to be addressed.
>
> What do others think?
>
'
After walking back through some diffs, it looks like we haven't touched the
Introduction for more than editorials since
https://www.ietf.org/rfcdiff?url2=draft-ietf-mops-streaming-opcons-04.txt,
and the abstract hasn't changed significantly since the draft was adopted
nearly two years ago.

If it would be helpful to provide a PR that describes the document more
clearly in the Abstract and Introduction, I'd be happy to do that, but
don't want to wander off into the weeds if people think that's a bad idea.

Please advise.

Spencer


>
> Thanks!
> -Mike
>
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