Re: [auth48] [C350] AUTH48: RFC-to-be 9332 <draft-ietf-tsvwg-aqm-dualq-coupled-25> for your review

[[e-mail]]

Authors,

While reviewing this document during AUTH48, please resolve (as necessary) the following questions, which are also in the XML file.

1) <!--[rfced] FYI, we have updated this document with the changes shown
in the -26 file sent by the authors. The diff from the approved I-D
is here:

https://www.rfc-editor.org/in-notes/authors/draft-ietf-tsvwg-aqm-dualq-coupled-25-26-rfcdiff.html

The primary change was the removal of informative reference [DCttH19].
-->


2) <!--[rfced] Please note that the title has been updated as
follows. Also, should "Algorithms" be included for clarity? 
Please review.

Original:
   DualQ Coupled AQMs for Low Latency, Low Loss and Scalable Throughput (L4S)

Current:
   Dual Queue Coupled Active Queue Management (AQM)     
   for Low Latency, Low Loss, and Scalable Throughput (L4S)

Perhaps:
   Dual Queue Coupled Active Queue Management (AQM) Algorithms 
   for Low Latency, Low Loss, and Scalable Throughput (L4S)
-->


3) <!-- [rfced] Some author comments are present in the XML. Please confirm
that no updates related to these comments are outstanding. Note that the
comments will be deleted prior to publication.
-->


4) <!-- [rfced] Please insert any keywords (beyond those that appear in the title)
for use on https://www.rfc-editor.org/search. -->


5) <!--[rfced] Regarding the expansion of L4S upon first mention in the abstract, 
would you like to update it to match the title? Or, add the expansion upon
second mention?

Current:
   These are designed for consistently very Low queuing Latency,
   very Low congestion Loss, and Scaling of per-flow throughput (L4S) ...

Perhaps:
   These are designed for consistently very Low Latency, Low Loss, and
   Scalable Throughput (L4S) ...
-->


6) <!--[rfced] Is the intention to include both "many" and "(most?)" in
the following, or should one be deleted? (A similar question was
asked regarding RFC-to-be 9331.)

Original:
   Latency is becoming the critical performance factor for many (most?)
   Internet applications, e.g. interactive Web, Web services, voice...
-->


7) <!-- [rfced] We note the use of <em> in some places. In the txt
output, the text enclosed in <em> appears with an underscore
before and after.  In the html and pdf outputs, the text enclosed
in <em> is output in italics.

Please review carefully and let us know if the output is acceptable 
or if any updates are desired.
-->


8) <!--[rfced] We have updated the Terminology section to match 
that of RFC-to-be 9331.

Note that the terms are not in the same order. Please review
the following diff file (created using a reordered list from this document).
This file compares definitions in 9331 vs. 9332:
https://www.rfc-editor.org/authors/rfc9331_vs_9332_term_diff.html

Differences that remain (please let us know any updates):
- This document includes the abbreviations (C and L); 9331 does not.
- For Scalable Congestion Control, the last sentence is different.
- This document does not reference [CTCP].
- This document has an additional sentence ("The DualQ Coupled AQM behaviour is ...")
- This document does not include "Site" in the terminology section, 
although it mentions 9330's definition in Section 1.2.
-->


9) <!--[rfced] May we add single quotes on the first term, as the 
text is referring to the term itself? (This appears in all 3 documents.)

Current:   Reno-friendly is used here in place of 'TCP-friendly'
Suggested: 'Reno-friendly' is used here in place of 'TCP-friendly'
-->


10) <!--[rfced] For the ease of the reader, would you like to include the
section number (perhaps Section 6.1) of the L4S architecture?

Original:
   Subjective testing using very demanding high bandwidth
   low latency applications over a single shared access link
   is also described in [L4Sdemo16] and summarized in the section about
   applications in the L4S architecture [I-D.ietf-tsvwg-l4s-arch].

Perhaps:
   Subjective testing using very demanding high-bandwidth
   low-latency applications over a single shared access link
   is also described in [L4Sdemo16] and summarized in Section 6.1 
   of the L4S architecture [RFC9330].
-->


11) <!--[rfced] Please review each artwork element in the XML file. Specifically,
should any artwork element be tagged as sourcecode or another element?
-->


12) <!--[rfced] We could not locate "MUST NOT alter these non-ECN
identifiers" in draft-ietf-tsvwg-ecn-l4s-id (or RFC-to-be 9331). 
Please let us know how this quote may be updated for accuracy.

Original:
   [I-D.ietf-tsvwg-ecn-l4s-id] says it "MUST NOT alter these non-ECN 
   identifiers". 

Section 5.4.1.1 of RFC-to-be 9331
(https://www.rfc-editor.org/authors/rfc9331.html#section-5.4.1.1) contains:

   In order to include non-L4S packets in the L queue, a network node
   MUST NOT alter Not-ECT or ECT(0) in the IP-ECN field of an L4S
   identifier. 
(Also, a question was sent regarding the change from "to" to "of".)
-->


13) <!--[rfced] Section 2.4. For clarity and consistency, may we remove the punctuation
from equations (2), (3), and (4)?

Original:
   p_C = (p')^2.                  (2)

   p_CL = k*p'.                   (3)

   p_L = max(p'_L, p_CL),         (4)

Perhaps:
   p_C = (p')^2                   (2)

   p_CL = k*p'                    (3)

   p_L = max(p'_L, p_CL)          (4)
-->


14) <!--[rfced] RFC 2309 has been obsoleted by RFC 7576. May we indicate this 
relationship by adding the following note? 

Original:
   Curvy RED is derived from RED [RFC2309], except its configuration
   parameters are delay-based to make them insensitive to link rate and
   it requires fewer operations per packet than RED. 

Perhaps:
   Curvy RED is derived from RED [RFC2309] (which was obsoleted by
   [RFC7576]), except its configuration parameters are delay-based to 
   make them insensitive to link rate, and it requires fewer operations 
   per packet than RED. 

(and adding RFC 7576 as a informative reference)
-->	


15) <!--[rfced] A newer version of this document is available.  We assume
you would like to keep this as is (January 2019) in order to match
the reference in RFC-to-be 9330 (rather than update to
Version I24 (October 2022)).

Original:
   [DOCSIS3.1]
              CableLabs, "MAC and Upper Layer Protocols Interface
              (MULPI) Specification, CM-SP-MULPIv3.1", Data-Over-Cable
              Service Interface Specifications DOCSIS® 3.1 Version i17
              or later, 21 January 2019, <https://specification-
              search.cablelabs.com/CM-SP-MULPIv3.1>.
-->	


16) <!-- [rfced] FYI, we have updated these references (as in RFC-to-be 9331)
as follows per the guidance in the "Web Portion of the Style Guide" at
https://www.rfc-editor.org/styleguide/part2/#ref_repo (see section titled
"Referencing Web-Based Public Code Repositories (e.g., GitHub)".

We did not make any changes to the titles chosen, but please note that the                
"Web Portion of the Style Guide" states that "some judgement may be required              
on the part of the editors and authors to have a sensible title". Please                  
review the titles as well as other changes in the updated reference entries to            
confirm accuracy.                                                                         

Original:                                                                                 
   [BBRv2]    Cardwell, N., "BRTCP BBR v2 Alpha/Preview Release", GitHub
              repository; Linux congestion control module,
              <https://github.com/google/bbr/blob/v2alpha/README.md>.

   [SCReAM]   Johansson, I., "SCReAM", GitHub repository; ,
              <https://github.com/EricssonResearch/scream/blob/master/
              README.md>.

   [Heist21]  Heist, P. and J. Morton, "L4S Tests", GitHub README,
              August 2021, <https://github.com/heistp/l4s-
              tests/#underutilization-with-bursty-traffic>.

Updated:                                                                                  
   [BBRv2]    "TCP BBR v2 Alpha/Preview Release", commit 17700ca, June
              2022, <https://github.com/google/bbr>.

   [SCReAM]   "SCReAM", commit fda6c53, June 2022,
              <https://github.com/EricssonResearch/scream>.

   [Heist21]  "L4S Tests", commit e21cd91, August 2021,
              <https://github.com/heistp/l4s-tests>.

   (with mention of "Underutilization with Bursty Links" added in text,
   similar to RFC-to-be 9331)
 -->


17) <!--[rfced] FYI: We have updated "<em>P</em>roportional” and
"<em>I</em>ntegral" to be "<em>Proportional</em>” and
"<em>Integral</em> for readability. Please let us know if you
prefer otherwise.

Text output:
Original: _P_roportional and _I_ntegral
Current: _Proportional_ and _Integral_ 
-->


18) <!--[rfced] May this be rephrased as follows or otherwise? This is to 
avoid "unrepresentatively", which reads oddly and does not appear 
in Merriam-Webster or a few other dictionaries. (The derivative
"unrepresentativeness" appears, but not "unrepresentatively".)

Original:
      Countries were ranked by
      number of Internet users, and once 90% of Internet users were
      covered, smaller countries were excluded to avoid
      unrepresentatively small sample sizes. 

Perhaps:
      Countries were ranked by
      number of Internet users, and once 90% of Internet users were
      covered, smaller countries were excluded to avoid
      small sample sizes that are not representative. 

Or simply:
      Countries were ranked by
      number of Internet users, and once 90% of Internet users were
      covered, smaller countries were excluded to avoid
      small sample sizes.
-->


19) <!--[rfced] Would it be correct to insert space between "25" and
"ms" for consistency, or should it be left as is? Also, should
Tupdate=16 ms have spacing around the equals sign (2 instances)?

Original:
   target = RTT_typ * g * f = 25ms * 0.38 * 2 = 19 ms

   Tupdate=16 ms

Perhaps:
   target = RTT_typ * g * f = 25 ms * 0.38 * 2 = 19 ms

   Tupdate = 16 ms
-->	      


20) <!--[rfced] To yield superscript, <sup> has been added.
Please let us know if you prefer otherwise, as we note
that you may want the lines to match the usage of "^" within 
artwork elements (in Figure 2, for example). This affects the 
HTML and PDF files. Also, please consider whether <sub> should be
used anywhere for subscript.

Example from Figure 2:
alpha = 0.1 * Tupdate / RTT_max^2
vs.
When using <sup>, it appears with a superscript "2" 
in the following paragraph in the HTML and PDF files.

One way to proceed would be to use <sup> only when the
base is a numeral (e.g., 2^32 and 2^2).
-->


21) <!--[rfced] Should "five" be updated to "three" in the following
lead-in text since there are only three main functions listed?

Original:
   The pseudocode manipulates three main structures of variables: the
   packet (pkt), the L4S queue (lq) and the Classic queue (cq) and
   consists of the following five functions:

   *  The initialization function cred_params_init(...) (Figure 2) that
      sets parameter defaults (the API for setting non-default values is
      omitted for brevity);

   *  The dequeue function cred_dequeue(lq, cq, pkt) (Figure 4);

   *  The scheduling function scheduler(), which selects between the
      head packets of the two queues.

   It also uses the following functions that are either shown elsewhere,
   or not shown in full here:

   *  The enqueue function, which is identical to that used for DualPI2,
      dualpi2_enqueue(lq, cq, pkt) in Figure 3;

   *  mark(pkt) and drop(pkt) for ECN-marking and dropping a packet;

   *  cq.byt() or lq.byt() returns the current length (aka. backlog) of
      the relevant queue in bytes;

   *  cq.time() or lq.time() returns the current queuing delay of the
      relevant queue in units of time (see Note a in Appendix A.1).
-->


22) <!--[rfced] FYI, for the XML that creates the links to Notes 1-3 
and Notes a-c (in the HTML and PDF files), rather than rely on the 
dynamic counter value, we decided to hard-code it so that 
"Note x" (rather than only the single character) is the linked text.
If you prefer otherwise, please let us know. For example:

Original XML:
Note <xref format="counter" target="dualq_note_dequeue"/>

Current XML:
<xref format="none" target="dualq_note_dequeue">Note 1</xref>
-->


23) <!--[rfced] Is "equation (1)" in Section 2.1, or should be readers be
directed to "(1)" within Appendix C.2? Please let us know if A or
B is correct.

Original:
   The coupling factor, k, determines the balance between L4S and
   Classic flow rates (see Section 2.5.2.1 and equation (1)).

Perhaps:
A) The coupling factor, k, determines the balance between L4S and
   Classic flow rates (see Section 2.5.2.1 and equation (1) below).

or 

B) The coupling factor, k, determines the balance between L4S and
   Classic flow rates (see Section 2.5.2.1 and equation (1) in
   Section 2.1).
-->


24) <!-- [rfced] Throughout the text, the following terminology appears to be used 
inconsistently. Please review these occurrences and let us know if/how they
may be made consistent.  

DualQ AQM vs. DualQ Coupled AQM
   [Note: Are these terms the same? If so, may we update 
    these 2 instances to include "Coupled":

   - the goal of a DualQ AQM is to behave no worse than a single-queue AQM.
   - Both FQ and DualQ AQMs can be enablers...
-->


25) <!-- [rfced] Please review the "Inclusive Language" portion of the online 
Style Guide <https://www.rfc-editor.org/styleguide/part2/#inclusive_language>
and let us know if any changes are needed.

For example, please consider whether "native" should be updated.

In addition, please consider whether "traditionally" should be updated for clarity.  
While the NIST website 
<https://www.nist.gov/nist-research-library/nist-technical-series-publications-author-instructions#table1> 
indicates that this term is potentially biased, it is also ambiguous.  
As noted there, "traditional" is a subjective term.
-->


Thank you.

RFC Editor/kc/ar



On Nov 23, 2022, at 10:17 PM, [e-mail] wrote:

*****IMPORTANT*****

Updated 2022/11/23

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--------------------------------------
RFC9332 (draft-ietf-tsvwg-aqm-dualq-coupled-25)

Title            : Dual Queue Coupled Active Queue Management (AQM) for Low Latency, Low Loss, and Scalable Throughput (L4S)
Author(s)        : K. De Schepper, B. Briscoe, Ed., G. White
WG Chair(s)      : Gorry Fairhurst, David L. Black, Marten Seemann

Area Director(s) : Martin Duke, Zaheduzzaman Sarker