Shared Bottleneck Detection for Coupled Congestion Control for RTP Media
draft-ietf-rmcat-sbd-11

[Ballot comment]
Thanks for everyone's work on this document, and especially to those who ran the
preliminary experiments. This sounds like an interesting technique. I have two
minor comments.

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§2:

>  The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
>  "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
>  "OPTIONAL" in this document are to be interpreted as described in BCP
>  14 [RFC2119] RFC2119 [RFC2119] RFC8174 [RFC8174] when, and only when,
>  they appear in all capitals, as shown here.

This is almost, but not quite, the boilerplate defined in RFC 8174. Please
consider fixing it.

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§2.1 says "Usually M=N", while §2.2 recommends N=50 and M=30. These statements
seem in conflict.

[Ballot comment]
I'm somewhat confused about whether the intended scope for this mechanism is to detect bottleneck links shared by all flows, or only what's shared by RTP media flows. The Abstract seems clear about that, but I'm not seeing a similar statement about scope in the Introduction, unless I'm missing it. Perhaps it's worth repeating the statement from the Abstract in the Introduction?

I agree with the last sentence in this paragraph,

  The current Internet is unable to explicitly inform endpoints as to
  which flows share bottlenecks, so endpoints need to infer this from
  whatever information is available to them.  The mechanism described
  here currently utilizes packet loss and packet delay, but is not
  restricted to these.  As ECN becomes more prevalent it too will
  become a valuable base signal.

and I'd believe that ECN helps identify path bottlenecks, but I'm not understanding how ECN helps identify shared bottlenecks, and I think that's the point being made here.

The following Last Call announcement was sent out (ends 2018-03-16):

From: The IESG
To: IETF-Announce
CC: rmcat-chairs@ietf.org, rmcat@ietf.org, draft-ietf-rmcat-sbd@ietf.org, ietf@kuehlewind.net, anna.brunstrom@kau.se, Anna Brunstrom
Reply-To: ietf@ietf.org
Sender:
Subject: EXTENDED Last Call:  (Shared Bottleneck Detection for Coupled Congestion Control for RTP Media.) to Experimental RFC


The IESG has received a request from the RTP Media Congestion Avoidance
Techniques WG (rmcat) to consider the following document: - 'Shared
Bottleneck Detection for Coupled Congestion Control for RTP
  Media.'
  as Experimental RFC

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2018-03-16. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the beginning of
the Subject line to allow automated sorting.

Abstract


  This document describes a mechanism to detect whether end-to-end data
  flows share a common bottleneck.  It relies on summary statistics
  that are calculated based on continuous measurements and used as
  input to a grouping algorithm that runs wherever the knowledge is
  needed.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-rmcat-sbd/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-rmcat-sbd/ballot/


No IPR declarations have been submitted directly on this I-D.

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

The IANA Services Operator has reviewed draft-ietf-rmcat-sbd-10, which is currently in Last Call, and has the following comments:

We understand that this document doesn't require any registry actions.

While it's often helpful for a document's IANA Considerations section to remain in place upon publication even if there are no actions, if the authors strongly prefer to remove it, we do not object.

If this assessment is not accurate, please respond as soon as possible.

Thank you,

Amanda Baber
Lead IANA Services Specialist

The following Last Call announcement was sent out (ends 2018-03-02):

From: The IESG
To: IETF-Announce
CC: rmcat-chairs@ietf.org, rmcat@ietf.org, draft-ietf-rmcat-sbd@ietf.org, ietf@kuehlewind.net, anna.brunstrom@kau.se, Anna Brunstrom
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Shared Bottleneck Detection for Coupled Congestion Control for RTP Media.) to Experimental RFC


The IESG has received a request from the RTP Media Congestion Avoidance
Techniques WG (rmcat) to consider the following document: - 'Shared
Bottleneck Detection for Coupled Congestion Control for RTP
  Media.'
  as Experimental RFC

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2018-03-02. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the beginning of
the Subject line to allow automated sorting.

Abstract


  This document describes a mechanism to detect whether end-to-end data
  flows share a common bottleneck.  It relies on summary statistics
  that are calculated based on continuous measurements and used as
  input to a grouping algorithm that runs wherever the knowledge is
  needed.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-rmcat-sbd/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-rmcat-sbd/ballot/


No IPR declarations have been submitted directly on this I-D.

1. Summary

The document shepherd is Anna Brunstrom (anna.brunstrom@kau.se)
The responsible Area Director is Mirja Kuehlewind (ietf@kuehlewind.net)

  This document describes a mechanism to detect whether end-to-end data
  flows share a common bottleneck.  It relies on summary statistics
  that are calculated based on continuous measurements and used as
  input to a grouping algorithm that runs wherever the knowledge is
  needed.  This mechanism complements the coupled congestion control
  mechanism in draft-ietf-rmcat-coupled-cc.

2. Review and Consensus

The draft has been under development in the RMCAT WG for some years, receiving several rounds of reviews. There seems general, but not overwhelming, consensus from the working group that the mechanism is useful and suitable for use together with coupled congestion control. There has been no controversial points.

3. Intellectual Property

Each author has confirmed that they do not have any direct, personal knowledge of any IPR related to this document.

4. Other Points

This document is experimental, as a number of algorithm parameters have to be tested under real network conditions, see Section 6 "Expected feedback from experiments". The current set of parameters have been mainly evaluated through simulation. The WG will collect the feedback from first experiments using SBD and use them to discuss further steps.