On Apr 2, 2026, at 12:08 AM,<[email protected]>
<[email protected]> wrote:
Dear Alice,
Many thanks! Well done!
I reviewed the changes with my co-authors and they all look well. I only have
some minor input below. Everything else if perfectly fine as you proposed.
Best wishes
Thomas
1
---
Keywords: Flow Record, Performance Metric, On-Path, Hybrid Type I, OAM
2
---
OLD:
This correlation enables the detection of changes in
forwarding paths, such as updated intermediate hops or interfaces,
and the resulting impact on delay experienced by customer traffic.
NEW:
This correlation enables the detection of changes in
forwarding paths, such as updated intermediate hops or interfaces,
and of the resulting impact on delay experienced by customer traffic.
3
---
OLD:
This category includes multiple indexes of the registered performance
metrics: the element Identifier and Metric Name.
NEW:
This category includes multiple indexes of the registered performance
metrics: the Identifier and Metric Name.
RFC editor remark: Identifier refers
tohttps://datatracker.ietf.org/doc/html/rfc8911#section-11.1.1 and Metric Name
tohttps://datatracker.ietf.org/doc/html/rfc8911#section-11.1.2
11
---
OLD:
The mean (average) path delay can be calculated by dividing the
pathDelaySumDeltaMicroseconds(533) by the packetDeltaCount(2) at the
IPFIX data collection in order to offload the IPFIX Exporter from
calculating the mean for every Flow at export time.
NEW:
The mean (average) path delay can be calculated by dividing the
pathDelaySumDeltaMicroseconds(533) by the packetDeltaCount(2) at the
IPFIX data collection at the collection time instead of the IPFIX Exporter at
the export time.
RFC editor remark: The sentence can optionally be further simplified by removing "at the
collection" and "at the export time".
18
---
OLD: flow record
NEW: Flow Record
OLD: Singleton
NEW: singleton
-----Original Message-----
From:[email protected] <[email protected]>
Sent: Tuesday, March 31, 2026 7:49 AM
To: Graf Thomas,
SCS-INI-NET-VNC-E2E<[email protected]>;[email protected];[email protected]
Cc:[email protected];[email protected];[email protected];[email protected];[email protected];[email protected]
Subject: Re: AUTH48: RFC-to-be 9951
<draft-ietf-opsawg-ipfix-on-path-telemetry-23> for your review
Be aware: This is an external email.
Authors,
While reviewing this document during AUTH48, please resolve (as necessary) the
following questions, which are also in the source file.
1) <!-- [rfced] Please insert any keywords (beyond those that appear in the title)
for use onhttps://www.rfc-editor.org/search. -->
2) <!--[rfced] Please clarify this sentence. Is the intended meaning
(i) "This correlation enables the detection of changes and of the impact."
or
(ii) "This correlation enables the detection and the impact."?
Original:
This correlation enables the detection of changes in
forwarding paths, such as updated intermediate hops or interfaces,
and the resulting impact on delay experienced by customer traffic.
Perhaps (assuming (i), adding a second "of"):
This correlation enables the detection of changes in
forwarding paths, such as updated intermediate hops or interfaces,
and of the resulting impact on delay experienced by customer traffic.
Or (assuming (i), for more precision):
This correlation enables the detection of (a) changes in
forwarding paths, such as updated intermediate hops or interfaces,
and (b) the resulting impact on delay experienced by customer traffic.
-->
3) <!--[rfced] Should "element Identifier" be "Information Element identifier"?
The latter term is used in RFC 7011 (which you had mentioned in the intake
form).
Original:
This category includes multiple indexes of the registered performance
metrics: the element Identifier and Metric Name.
-->
4) <!--[rfced] FYI, we added "is" to make the 2nd sentence complete in each
definition below. Please let us know if a different meaning was intended.
For example:
Original:
The measurement of one-way delay based on a single Observation Point
[RFC7011] somewhere in the network.
Current:
The measurement of one-way delay is based on a single Observation Point
[RFC7011] somewhere in the network.
-->
5) <!-- [rfced] FYI, we corrected this section number as follows; please review.
Section 2 of [RFC2330] is the copyright statement; the terms mentioned are
defined in Section 11 of [RFC2330].
Original:
Note that terms such as "singleton" and "sample" are defined in
Section 2 of [RFC2330].
Perhaps:
Note that terms such as "singleton" and "sample" are defined in
Section 11 of [RFC2330].
-->
6) <!-- [rfced] RFC 6991 has been obsoleted by RFC 9911. We have replaced each
citation of RFC 6991 with RFC 9911, as the section numbers seem to contain the
data types being mentioned. Please review and let us know any further updates. For
example:
Original: or ipv6-address-no-zone value for IPv6; see Section 4 of [RFC6991]).
Current: or ipv6-address-no-zone value for IPv6; see Section 4 of [RFC9911]).
-->
7) <!--[rfced] We suggest changing "analysis choice" (4 instances) to "analytic choice" or
"analytical choice", because "analysis" is a noun.
We note the term "analysis choice" is only used RFC 8912. For example:
Original:
see Section 5 of [RFC6703] for background on this analysis choice.
Suggested:
see Section 5 of [RFC6703] for background on this analytic choice.
-->
8) <!--[rfced] FYI, Revision Date will be updated before publication.-->
9) <!--[rfced] Please clarify "as defined to the following [...] dimensions"; should it
be "as defined across the following [...] dimensions"?
Original:
The measured On-Path delay can be aggregated with Flow Aggregation as
defined in [RFC7015] to the following device and control-plane
dimensions [IANA-IPFIX] to determine:
Perhaps:
The measured On-Path delay can be aggregated with Flow Aggregation as
defined in [RFC7015] across the following device and control-plane
dimensions [IANA-IPFIX] to determine:
-->
10) <!-- [rfced] FYI, we simplified this sentence as follows; please review.
Original:
Let us consider the example depicted in Figure 1 from Section 1 as
topology example.
Current:
Let us consider Figure 1 as a topology example.
-->
11) <!--[rfced] How may this be rephrased to avoid the odd phrase "offload the IPFIX
Exporter from calculating the mean"?
Specifically, rather than "offload X from doing a task", we can offload the
task - or we can offload X by doing the task elsewhere.
Original:
The mean (average) path delay can be calculated by dividing the
pathDelaySumDeltaMicroseconds(533) by the packetDeltaCount(2) at the
IPFIX data collection in order to offload the IPFIX Exporter from
calculating the mean for every Flow at export time.
Perhaps ("offload" changed to "prevent"):
The mean (average) path delay can be calculated by dividing the
pathDelaySumDeltaMicroseconds(533) by the packetDeltaCount(2) at the
IPFIX data collection in order to prevent the IPFIX Exporter from
calculating the mean for every Flow at export time.
-->
12) <!--[rfced] We suggest changing "being accounted" to "being counted" here.
Please review the intended meaning.
Original:
Unsigned64 has been chosen as type for pathDelaySumDeltaMicroseconds
to support cases with large delay numbers and where many packets are
being accounted.
Perhaps:
Unsigned64 has been chosen as type for pathDelaySumDeltaMicroseconds
to support cases with large delay numbers and where many packets are
being counted.
-->
13) <!--[rfced] Should "node" be plural "nodes"? In other words, is this about
both an intermediate node and decapsulating node?
Also, is it accurate that "on-path delay" should be "On-Path delay" as it is
elsewhere in this document?
Original:
[...] and be read at the OAM header intermediate and decapsulating
node to calculate the on-path delay.
Perhaps:
[...] and be read at the OAM header intermediate and decapsulating
nodes to calculate the On-Path delay.
-->
14) <!--[rfced] Is the intended meaning that attacks by the receiver may be possible? If so, we
suggest changing "for" to "by" or rephrasing otherwise.
Original:
For example, exporting delay metrics may make attacks possible for
the receiver of this information; ...
Perhaps:
For example, exporting delay metrics may make attacks possible by
the receiver of this information; ...
-->
15) <!-- [rfced] [RFC7012] is not cited in the text. Please let us know where
it should be cited; otherwise it will be deleted from the references section.
[RFC7012] Claise, B., Ed. and B. Trammell, Ed., "Information Model for
IP Flow Information Export (IPFIX)", RFC 7012, DOI 10.17487/RFC7012,
September 2013,<https://www.rfc-editor.org/info/rfc7012>.
-->
16) <!-- [rfced] FYI, this sentence has been updated to remove the pointer to
Section 1. Rationale: Figure 1 is specific enough for the reader to find the
information. And it's in Section 3, not Section 1.
Original:
Taking Figure 1 from Section 1 as topology example.
Current:
Let's take Figure 1 as a topology example.
-->
17) <!--[rfced] For Table 4, is it correct that the column headers are intended
as the names of the IEs? If so, we recommend rotating the table (so the column
headers become the first column) as shown in the edited document. Please review
and let us know any updates, or if you want to revert to the previous format. (We
note that Table 2 also adds spaces into IE names, perhaps in order get line breaks
within the cell; please let us know if you'd like to make any updates to Table 2.)
Original (column headers):
path Delay Mean Delta Micro..
path Delay Min Delta Micro..
path Delay Max Delta Micro..
Perhaps intended as the IE names:
pathDelayMeanDeltaMicroseconds
pathDelayMinDeltaMicroseconds
pathDelayMaxDeltaMicroseconds
-->
18) <!--[rfced] Terminology: Please review usage of these terms and let us know
if any updates should be made for consistency.
Flow Record (8 instances) vs. flow record (1 instance)
Singleton (2 instances) vs. singleton (5 instances)
-->
19) <!-- [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. Updates of this nature typically
result in more precise language, which is helpful for readers.
Note that our script did not flag any words in particular, but this should
still be reviewed as a best practice.
-->
Thank you.
Alice Russo
RFC Production Center
On Mar 30, 2026,[email protected] wrote:
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--------------------------------------
RFC9951 (draft-ietf-opsawg-ipfix-on-path-telemetry-23)
Title : Export of Delay Performance Metrics in IP Flow Information
Export (IPFIX)
Author(s) : T. Graf, B. Claise, A. Huang-Feng
WG Chair(s) : Joe Clarke, Benoît Claise
Area Director(s) : Mohamed Boucadair, Mahesh Jethanandani
