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

[Leslie Daigle <[e-mail]>]

Mike,

Thanks for taking the time to read through the document and share your 
thoughts.  I think it’s certainly fair to say that, if this is how the 
document struck you, there’s some discussion to be had (and maybe some 
work to be done) before sending it out for broader IETF review.

Taking my co-chair hat off, for a moment, here are a few of my own 
thoughts:

I’m not so sure the document has an ill-defined purpose as that it may 
not yet be well-expressed.  I believe the document outlines “Video on 
the Internet is a Thing; and here are some of the ways in which video 
will bite you on the backside if you’re not careful, whether you are 
operating a network, deploying a service, or working on related 
protocols”.

I’ll agree that’s not what the abstract says (even adjusting for my 
exaggeratedly lighthearted expression of it :-) ).   But would that do a 
better job of setting your expectations?

Leslie.


On 10 Dec 2021, at 14:05, Mike English 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?
>
> Thanks!
> -Mike
>
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Leslie Daigle
Principal, ThinkingCat Enterprises
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