Re: [xrblock] AD Evaluation of draft-ietf-xrblock-rtcweb-rtcp-xr-metrics-06

[Roni Even <[e-mail]>]

Hi 
Just to clarify, the individual draft started as an Informational draft and just before becoming a WG draft it was changed to standard track. We see no WG decision for this and as Rachel said, Informational is OK
Roni

> -----Original Message-----
> From: xrblock [mailto:[e-mail]] On Behalf Of Huangyihong
> (Rachel)
> Sent: יום ה 02 נובמבר 2017 12:01
> To: Ben Campbell; Varun Singh
> Cc: [e-mail]; xrblock
> Subject: Re: [xrblock] AD Evaluation of draft-ietf-xrblock-rtcweb-rtcp-xr-
> metrics-06
> 
> Hi Ben,
> 
> After discussion among the co-authors, we reached the consensus to make it
> informational. W3C stats API still refers to it, but in an informational way.
> We'll submit a new version to address your comments.
> 
> BR,
> Rachel
> 
> > -----Original Message-----
> > From: Ben Campbell [mailto:[e-mail]]
> > Sent: Friday, October 13, 2017 5:52 AM
> > To: Varun Singh
> > Cc: [e-mail]; xrblock
> > Subject: Re: [xrblock] AD Evaluation of
> > draft-ietf-xrblock-rtcweb-rtcp-xr-metrics-06
> >
> > >
> > > On Oct 8, 2017, at 8:11 AM, Varun Singh <[e-mail]> wrote:
> > >
> > > Hi Ben,
> > >
> > > See inline.
> > >
> > >> On Tue, Oct 3, 2017 at 12:28 AM, Ben Campbell <[e-mail]>
> > wrote:
> > >> Hi,
> > >>
> > >> This is my AD Evaluation of
> > >> draft-ietf-xrblock-rtcweb-rtcp-xr-metrics-06. I
> > would like to resolve at least the substantive comments prior to IETF LC.
> > >>
> > >> Thanks!
> > >>
> > >> Ben.
> > >> —————————
> > >>
> > >> Substantive:
> > >>
> > >> - General: If I understand correctly, this document lists and
> > >> describes XR
> > metrics that a WebRTC application might choose to negotiate and expose
> > via the WebRTC API. It does not define any new XR metrics. That brings
> > up two
> > questions:
> > >>
> > >> 1) Why is this specific to WebRTC? For the most parts, all the
> > >> arguments
> > here would apply to any sort of RTP endpoint.
> > >>
> > >
> > > This draft was created initially as an input to RTCWEB and later as
> > > an input to WebRTC Statistics API. Hence the use of WebRTC in the
> > > title and the introduction. We could add to the introduction: "In
> > > general, the metrics listed in this document can be exposed by any
> > > real-time communications endpoint." Or something along those lines
> > >
> > >
> > >> 2) Why is this standards track? This sort of material is typically
> > >> informational,
> > or occasionally a BCP. There are a small number of 2119 keywords, but
> > I’m not sure they are needed or appropriate. (Specifics below.) My
> > initial instinct is that this should be informational.
> > >>
> > >
> > > The reason until recently (perhaps still exist) is that this was an
> > > input from the IETF to W3C, I am not sure if there was an official
> > > liaison statements sent to them? nonetheless, the W3C Statistics API
> > > document needed a specification needed (a specification in any
> > > standards body would suffice) for metrics to be accepted into the
> > > W3C document.
> >
> > To make sure I understand:That API document will reference this one?
> > Do they require that specification to be standards track?
> >
> > Was there discussion in xrblock about standards track verses BCP?
> >
> > >
> > > In practice, it helped that I was the co-author of both the IETF and
> > > W3C document and hence was able to make the case for the metrics in
> > > W3C.
> >
> > Is that case already made? That is, does the need for a published RFC
> > still exist?
> >
> > >
> > >> - General: This needs an IANA considerations section, even if it
> > >> just contains
> > the statement to the effect of “This document makes no requests for
> IANA”.
> > >>
> > >> - 1, last paragraph: “ The document also creates a registry
> > >> containing
> > identifiers from the metrics reported in the RTCP Sender, Receiver,
> > and Extended Reports.”
> > >
> > > This should be removed. Thanks for pointing this out.
> > >
> > >>
> > >> It doesn’t actually do that. I understand from the shepherd’s
> > >> report that
> > this was intentionally removed.
> > >>
> > >> — “All identifiers proposed in this document are RECOMMENDED to be
> > >> implemented by an endpoint.  An endpoint MAY choose not to expose
> > >> an identifier if it does not implement the corresponding RTCP
> > >> Report. “
> > >>
> > >> Does the “RECOMMENDED” apply to all endpoints or just WebRTC
> > >> endpoints? If the latter, doesn’t that requirement belong (or need
> > >> to
> > >> update) some requirement from an RTCWEB (maybe rtp-usage)
> document,
> > >> or even the API itself? (I suspect that this draft does not have
> > >> standing to state this normatively.) What is meant by “MAY choose
> > >> not to expose”. Is that talking about via the WebRTC API? If so,
> > >> isn’t that up to the API definition? (That is, it shouldn’t be
> > >> normative
> > >> here.)
> > >>
> > >
> > > It should be applicable to any endpoint, although it is pertinent or
> > > timely for the WebRTC endpoint to expose these.
> > > The purpose of the statement was to highlight that if the
> > > middlebox/endpoint sends RTCP XRs then it should expose the data
> > > available via the API.
> > >
> > > I am open to changing to a non-normative lower case guidance if that
> > > would be more suitable, although if this document is making
> > > recommendations to the W3C document -- wouldn't we keep the
> uppercase?
> >
> > In general, 2119 keywords are better used when we are talking about
> > interoperability issues in a protocol. I suggest switching to lower
> > case unless there’s some reason to believe the W3C won’t pay attention
> > unless it’s in all-caps. (I don’t think that’s usually the case.)
> >
> > >
> > > co-authors, what do you think?
> > >
> > >> -2: If this document keeps the normative keywords, please use the
> > >> updated boilerplate from RFC 8174. (I note that there are at least
> > >> some uncapitalized “may”s that do not seem normative.)
> > >>
> > >
> > > depending on the above, we should fix these to uppercase.
> > >
> > >> - 5.2.2, last paragraph: “The following metrics can also be considered…”
> > >> Be considered by whom? Implementors? API designers?
> > >>
> > >
> > > Both.
> > >
> > >> - 6, first paragraph: “In practice the application MUST be able to
> > >> query the
> > statistic identifiers on both an incoming (remote) and outgoing
> > (local) media stream.”
> > >> What does the MUST requirement apply to? The WebRTC API? This
> seems
> > more like a statement of fact that “ the application needs to be able…”
> > >>
> > >
> > > correct, "needs to" is better.
> > >
> > >> -8: "Therefore encryption procedures, such as the ones suggested
> > >> for a
> > Secure RTCP (SRTCP), need to be used.”
> > >> The text should describe the reasons encryption is needed. Also, is
> > >> this a
> > new normative requirement, or a restatement of an existing requirement?
> > >>
> > >
> > > I believe it is restatement alluding to the guidance in the
> > > corresponding RTCP XRs.
> > >
> > >> Editorial:
> > >>
> > >> -1, paragraph 1:" If sufficient information (metrics or statistics)
> > >> are provided to the applications, it can attempt to improve the
> > >> media quality. “
> > >>
> > >> s / “are provided” / “is provided”
> > >> s / applications / application
> > >>
> > >> -3, 2nd paragraph: It would help to clarify that the references to
> > >> section 5
> > and 6 are to this document, not RFC 3611.
> > >>
> > >> — 3rd paragraph: "At the moment…”
> > >> Please clarify that is at the time of writing (not reading)
> > >>
> > >> -5, 2nd paragraph: “ Application impact metrics mainly collect the
> > >> information in the viewpoint of application … “ s / in / from Also,
> > >> please expand “FEC” on first mention.
> > >>
> > >> - 5.1.1, first paragraph: “ Duplicate packets may be a result of
> > >> network
> > delays, which causes the sender to retransmit the original packets.”
> > >> s/ :delays, which” / “delays that”
> > >>
> > >> — last paragraph: "For those RTCWEB services with jitter buffer…”
> > >> s/buffer/buffers
> > >>
> > >> - 5.1.2, first paragraph:
> > >> First sentence is a comma splice.
> > >> — “some transitory nature of the impairments”
> > >> Should this say “the transitory nature of some impairments”?
> > >> — “ Distributed burst provides a higher subjective quality”
> > >> “Burst distribution …”?
> > >> — Last paragraph: “ Hence, if WebRTC application”
> > >> Missing article (or should application be plural?)
> > >>
> > >> - 5.2.1, title: Should “Discard” be “Discarded”?
> > >>
> > >> -7: Please clarify that this is at the time of this writing.
> > >>
> > >
> > > Thanks for your feedback and suggestions, we will fix these.
> > >
> > > Regards,
> > > Varun
> > >
> > >
> > > --
> > > Founder, CEO, callstats.io
> > > http://www.callstats.io
> > >
> > > Interested in networking, media quality, and diagnostics.
> > > We are hiring!: www.callstats.io/jobs/
> 
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