Re: [auth48] AUTH48: RFC-to-be 9544 <draft-ietf-ippm-pam-09> for your review

[Joel Halpern <[e-mail]>]

I can live with all the changes as proposed.

If I am reading item 7 correctly, I think that is “referred to by”.  I can live with many forms, but I think “between the elements of the network that are referred to the SLO” will cause many people reading difficulty.
Yours,
Joel

From: Greg Mirsky <[e-mail]>
Sent: Friday, February 16, 2024 8:45 PM
To: [e-mail]
Cc: Joel Halpern <[e-mail]>; [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail]; [e-mail]
Subject: Re: AUTH48: RFC-to-be 9544 <draft-ietf-ippm-pam-09> for your review

Dear RFC Editor,
thank you for your thoughtful proposals helping in improving the document. Please find my responses and notes below tagged GIM>>.

Regards,
Greg

On Thu, Feb 15, 2024 at 5:39 PM <[e-mail]<mailto:[e-mail]>> wrote:
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 updated the abbreviated title (appears in the center of
the running header in the pdf output) to more closely align with the
document title. Please let us know any objections.

Original:
   Framework of PAM

Current:
   PAM for Services Governed by SLOs
GIM>> I agree with the update with a minor modification
PAMs for Service Governed by SLOs
I've looked at the title itself and wanted to ask you and the co-authors a question. The title introduces the SLO acronym, should the PAM acronym also be introduced in the title as

 Precision Availability Metrics (PAMs) for Services Governed by Service Level Objectives (SLOs)
-->


2) <!-- [rfced] How may we update the text after the comma to improve clarity?

Original:
   Hence it is not sufficient to measure service levels
   per se over time, but to assess the quality of the service being
   contextually provided (e.g., with the applicable SLO in mind).

Perhaps:
   Hence, it is not sufficient to measure service levels
   per se over time; the quality of the service being
   contextually provided (e.g., with the applicable SLO in mind) must be also assessed.
GIM>> I agree with the proposed update. It makes the text more readable.
-->


3) <!-- [rfced] May we update the text starting with ", and whether their
SLOs..." as follows for to create parallel structure?

Original:
   However, at this point, there are no standard metrics that can be
   used to account for the quality with which services are delivered
   relative to their SLOs, and whether their SLOs are being met at all
   times.

Perhaps:
   However, at this point, there are no standard metrics that can be
   used to account for the quality with which services are delivered
   relative to their SLOs or to determine whether their SLOs are being met at all
   times.
GIM>> I agree with the proposed update that improves the text. I wonder if s/or/nor/ is acceptable in this sentence?

-->


4) <!-- [rfced] We see the term "Flow Record" in RFC 7011 but not in RFC 7012
(though "flow" does appear). Please review the citations and let us know
if any updates are needed.

Original:
   Flow records [RFC7011] and
   [RFC7012] maintain statistics about flows, including flow volume and
   flow duration, but again, contain very little information about
   service levels, let alone whether the service levels delivered meet
   their respective targets, i.e., their associated SLOs.
GIM>> Thank you for your thoughtful question. I think that reference to RFC 7012 is justified as it refers, as you've noted, to 'Flow' and 'Flow information'.
-->


5) <!-- [rfced] FYI - We updated the title of Section 2 from "Conventions and
Terminology" to "Conventions" because "Terminology" is one of the
subsections. Please review and let us know any concerns.

Original:
   2.  Conventions and Terminology
     2.1. Terminology
     2.2. Acronyms

Current:
   2.  Conventions
     2.1. Terminology
     2.2. Acronyms
GIM>> I agree with the update
-->


6) <!-- [rfced] Is "configurable optimal level threshold" correct here? Should
this read "configurable optimal threshold" (i.e., no "level") or "configurable
optimal level (i.e., no "threshold")?

Original:
   *  VI is a time interval during which at least one of the performance
      parameters degraded below its configurable optimal level
      threshold.

Perhaps:
   *  VI is a time interval during which at least one of the performance
      parameters degraded below its configurable optimal
      threshold.
GIM>> Thank you for pointing out that "threshold" and "level" are synonyms. I slightly prefer the first option (above), but I can live with the other proposal (below)

Or:
   *  VI is a time interval during which at least one of the performance
      parameters degraded below its configurable optimal
      level.
-->


7) <!-- [rfced] Please confirm that "referred to for" is correct. Or should this
be updated to "referred to", "referred for", or something else?

Original:
   The monitoring of performance parameters to determine the quality of
   an interval is performed between the elements of the network that are
   referred to for the SLO corresponding to the performance parameter.
GIM>> I think that it should be "referred to".
-->


8) <!-- [rfced] How may we update "this allows distinguishing" here?

Original:
   For example, this allows distinguishing between cases in
   which violated intervals are caused by isolated violation occurrences
   (such as, a sporadic issue that may be caused by a temporary spike in
   a queue depth along the packet's path) or by broad violations across
   multiple packets (such as a problem with slow route convergence
   across the network or more foundational issues such as insufficient
   network resources).

Perhaps ("this allows a service provider to distinguish"):
   For example, this allows a service provider to distinguish between cases in
   which violated intervals are caused by isolated violation occurrences
   (such as a sporadic issue that may be caused by a temporary spike in
   a queue depth along the packet's path) or by broad violations across
   multiple packets (such as a problem with slow route convergence
   across the network or more foundational issues such as insufficient
   network resources).

Or ("this allows for distinguishing"):
   For example, this allows for distinguishing between cases in
   which violated intervals are caused by isolated violation occurrences
   (such as a sporadic issue that may be caused by a temporary spike in
   a queue depth along the packet's path) or by broad violations across
   multiple packets (such as a problem with slow route convergence
   across the network or more foundational issues such as insufficient
   network resources).
GIM>> I slightly prefer the latter option as the act of attributing degradation to a cause could be performed by a function, not an operator. But I can live with the former option.

-->


9) <!-- [rfced] This sentence appears in Section 3.2 and points to Section
3. Should "introduced in Section 3" either be removed or updated to "introduced
in this document"? Also, is this sentence introducing the bulleted list
that appear after the paragraph? If so, would adding "The following" be
helpful?

Original:
   A set of metrics can be created based on PAM introduced in Section 3.

Perhaps (omit section pointer):
   The following set of metrics can be created based on PAM.

Or (use "in this document" instead of section pointer):
   The following set of metrics can be created based on PAM as introduced
   in this document.
GIM>> I slightly prefer the latter option, but I can live with the first one.
-->


10) <!-- [rfced] We updated the first two bulleted lists in Section 3.2 (created
parallel structure and removed the parentheses around sentences). Please
review these changes in the diff file and let us know any concerns.
GIM>> I agree with the update that makes looks of lists in the document consistent.
-->


11) <!-- [rfced] May we change the first bulleted list in Sections 3.1 and all
the bulleted lists in Section 3.2 to definition lists? See
https://authors.ietf.org/en/rfcxml-vocabulary#dl.

One example:

Current:
   *  VI is a time interval during which at least one of the performance
      parameters degraded below its configurable optimal level
      threshold.

   *  SVI is a time interval during which at least one of the
      performance parameters degraded below its configurable critical
      threshold.

   *  Consequently, VFI is a time interval during which all performance
      parameters are at or better than their respective pre-defined
      optimal levels.

Perhaps:
   VI: A time interval during which at least one of the performance
      parameters degraded below its configurable optimal level
      threshold.

   SVI: A time interval during which at least one of the
      performance parameters degraded below its configurable critical
      threshold.

   VFI: A time interval during which all performance
      parameters are at or better than their respective pre-defined
      optimal levels.
GIM>> I slightly prefer the current format, but I can live with the update.
-->


12) <!-- [rfced] Should "the following section" here read "this section"? This
sentence appears in Section 3.3; the following section is Section 4,
which does not mention a state model.

Original:
   While the definition of a service state model is outside the scope of
   this document, the following section provides some considerations for
   how such a state model and accompanying configuration settings could
   be defined.

Perhaps:
   While the definition of a service state model is outside the scope of
   this document, this section provides some considerations for
   how such a state model and accompanying configuration settings could
   be defined.
GIM>> Thank you for your thoughtful consideration of the text. I agree with the proposed update.
-->


13) <!-- [rfced] Would it be helpful to update "YANG/NETCONF/RESTCONF framework"
as follows? Or do you prefer the current?

Original:
   *  A YANG data model will allow PAM to be incorporated into
      monitoring applications based on the YANG/NETCONF/RESTCONF
      framework.

Perhaps:
   *  A YANG data model will allow PAM to be incorporated into
      monitoring applications based on the YANG, NETCONF,
      and RESTCONF frameworks.
GIM>> I agree with the proposed update.

-->


14) <!-- [rfced] FYI - We rephrased this as follows to form a complete
sentence. The other items in the list are complete sentences. Please
review.

Original:
   *  The definition of the metrics that represent histograms for
      service level parameters with buckets corresponding to individual
      service level objectives,

Updated:
   *  Metrics can be defined to represent histograms for
      service-level parameters with buckets corresponding to individual
      SLOs..
GIM>> I agree with the proposed update.
-->


15) <!-- [rfced] Please review "that should be maintained". Should this read "and
should be maintained", or is the current okay? Also, please confirm that
"violated time units" is correct here. We do not see this mentioned
elsewhere in the document.

Original:
   The same service levels that
   constitute SLO violations for one flow that should be maintained as
   part of the "violated time units" and related metrics, may be
   compliant for another flow.

Perhaps:
   The same service levels that
   constitute SLO violations for one flow and should be maintained as
   part of the "violated time units" and related metrics may be
   compliant for another flow.
GIM>> I agree with the updated version.

-->


16) <!-- [rfced] FYI - We updated this fragment as follows to create a complete
sentence.

Original:
   By the same token, where the definition of what constitutes a
   "severe" or a "significant" violation depends on configuration
   settings or context.

Perhaps:
   By the same token, the definition of what constitutes a
   "severe" or a "significant" violation depends on configuration
   settings or context.
GIM>> I agree with the proposed update.

-->


17) <!-- [rfced] Abbreviations

a) We see both of the following as the expansion for PAM.

  Precision Availability Metric (1 instance)
  Precision Availability Metrics (8 instances)

We updated to use the latter form (i.e., the form with "Metrics"). Please let
us know any objections.
GIM>> Thank you for the question. I think that the use of singular, i.e., "Metric", in Acronyms is valid. Consequently, all acronyms in the document, in my opinion, should be changed to "PAMs".


b) We see two instances of "PAMs" in the document (see below). Since "Metrics"
in the expansion is already plural, is the "s" needed in "PAMs"? Please
review.

Original:
   To indicate a historic degree of precision availability, additional
   derived PAMs can be defined as follows:
   ...
   It might be useful for a service provider to determine the current
   condition of the service for which PAMs are maintained.
GIM>> If we agree that the acronym is expanded as "Precision Availability Metric", then "PAMs" is the right form.



c) OAM appears in the list of acronyms in Section 2.2 but is not mentioned
elsewhere in the document. May we delete this term from the list?
GIM>> Yes, please remove it.


d) FYI - We have added an expansion for the following abbreviation
per Section 3.6 of RFC 7322 ("RFC Style Guide"). Please review each
expansion in the document carefully to ensure correctness.

  IP Flow Information Export (IPFIX)
GIM>> It seems that IPFIX is used only one time in the document. Do you think that the expanded form without the acronym is sufficient? I'm okay with any form.
-->


18) <!-- [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.

Note that our script did not flag any words in particular, but this should
still be reviewed as a best practice.
GIM>> I agree, don't find anything that requires rewording.
-->


19) <!-- [rfced] We see a number of author-inserted comments in the .xml file for
this document. We are unsure if these have been resolved. Please review
and let us know if these can be deleted or if they need to be addressed.
GIM>> :-) My apologies for not cleaning our workspace properly. Thank you.
-->


Thank you.

RFC Editor/rv



On Feb 15, 2024, at 5:34 PM, [e-mail]<mailto:[e-mail]> wrote:

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--------------------------------------
RFC9544 (draft-ietf-ippm-pam-09)

Title            : Precision Availability Metrics for Services Governed by Service Level Objectives (SLOs)
Author(s)        : G. Mirsky, J. Halpern, X. Min, A. Clemm, J. Strassner, J. François
WG Chair(s)      : Marcus Ihlar, Tommy Pauly
Area Director(s) : Martin Duke, Zaheduzzaman Sarker