Hi Greg,

Just a ping on this. Thank you.

Best regards,

David Dong
IANA Services Sr. Specialist

On Thu Sep 11 07:04:53 2025, [email protected] wrote:
> Dear Greg,
> 
> 
> 
> On behalf of the authors. We received feedback from Deb, Gunter, Med
> and Greg and decided to publish revision -21.
> 
> 
> 
> https://author-tools.ietf.org/diff?doc_1=draft-ietf-opsawg-ipfix-on-
> path-telemetry-21
> 
> 
> 
> From what we understand from this conversation is that there is one
> open item regarding the naming of the performance metrics.
> 
> 
> 
> We are also expecting feedback from Éric, Tim, Gorry and Mike and
> based on their and the discussion with you we will merge the input in
> -22.
> 
> 
> 
> Best wishes
> 
> Thomas
> 
> From: Graf Thomas, SCS-INI-NET-VNC-E2E
> Sent: Monday, September 8, 2025 8:43 AM
> To: Greg Mirsky <[email protected]>
> Cc: [email protected]; Michael.Scharf@hs-
> esslingen.de; [email protected]; [email protected]
> Subject: RE: [OPSAWG]Re: [IANA #1422930] expert review for draft-ietf-
> opsawg-ipfix-on-path-telemetry (performance-metrics)
> 
> Dear Greg,
> 
> Thanks a lot. See my reply inline.
> 
> Best wishes
> Thomas
> 
> From: Greg Mirsky
> <[email protected]<mailto:[email protected]>>
> Sent: Monday, September 8, 2025 2:53 AM
> To: Graf Thomas, SCS-INI-NET-VNC-E2E
> <[email protected]<mailto:[email protected]>>
> Cc: [email protected]<mailto:drafts-expert-review-
> [email protected]>; Michael.Scharf@hs-
> esslingen.de<mailto:[email protected]>;
> [email protected]<mailto:[email protected]>;
> [email protected]<mailto:[email protected]>
> Subject: Re: [OPSAWG]Re: [IANA #1422930] expert review for draft-ietf-
> opsawg-ipfix-on-path-telemetry (performance-metrics)
> 
> Be aware: This is an external email.
> 
> Dear Thomas,
> thank you for adding more structure to the discussion. Please find my
> follow-up notes below tagged GIM2>>.
> 
> Regards,
> Greg
> 
> On Sat, Sep 6, 2025 at 11:48 PM
> <[email protected]<mailto:[email protected]>> wrote:
> Dear Greg,
> 
> GIM>> I probably was not clear in my notes. My question is Why Hybrid
> GIM>> Type 1 and Passive are concatenated in IE's name, e.g.,
> GIM>> OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Sum?
> 
> TG> The reason why passive is chosen is because of the document scope:
> TG> Export of Delay Performance Metrics in IPFIX. The IPFIX process
> TG> passively observes IP flows. Section 4.3.2, Packet Stream
> TG> Generation, starts with "The time when the packet is being received
> TG> at the OAM header encapsulating node" therefore.
> 
> GM> thought that Passive refers to the measurement method, not the
> GM> method of collecting metrics
> 
> Thans a lot. I think we misunderstand each other. We need to
> distinguish between the performance metrics definition which includes
> 'method AND metrics' and the IPFIX where 'metrics' are defined.
> 
> Section 4.1.1.2 of draft-ietf-opsawg-ipfix-on-path-telemetry-21
> defines the name of the performance metrics. The document follows the
> guideline from https://datatracker.ietf.org/doc/html/rfc8911#section-
> 7.1.2 which includes RFC 7799 terminology and how it applies in
> performance metrics naming.
> https://datatracker.ietf.org/doc/html/rfc8912 is the first document
> describing performance metrics following those guidelines. Section 4
> of draft-ietf-opsawg-ipfix-on-path-telemetry-21 follows the criteria
> in https://datatracker.ietf.org/doc/html/rfc8911#section-5 where one
> objective is "accurate in terms of producing equivalent results".
> 
> https://www.rfc-editor.org/rfc/rfc7013.html#section-4.1 gives guidance
> on IPFIX entity naming. Even though
> https://datatracker.ietf.org/doc/html/rfc8911#section-1 intend is to
> facilitate a centralize performance metrics which can be then
> referenced when being used in data models of telemetry protocols such
> as IPFIX or YANG, it does not give guidance on naming those data
> elements. This makes sense to me since IPFIX and YANG as example
> models and name data differently. Have different taxonomies.
> 
> Taking https://datatracker.ietf.org/doc/html/rfc8911#section-7.1.2 as
> naming guidance, do you agree that the following names match the
> guidance or do you propose a different more appropriate name?
> 
> 4.1.1.2.  Name
> OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Mean
> OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Min
> OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Max
> OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Sum
> GIM2>> I have two questions to use of HybridType1 and Passive in the
> GIM2>> naming performance metrics:
> 
> *   RFC 7799 defines Hybrid Type 1 measurement methods as follows:
>     Augmentation or modification of the stream of interest, or
>     employment of methods that modify the treatment of the stream
> Should note that "stream" here is interpreted as a flow of data, i.e.,
> customer's, packets. On the other hand, since the publication of RFC
> 9197 and RFC 9326, where only combination of IOAM shim with a data
> packet is considered, we have drafts that propose combining IOAM shim
> with, for example, STAMP packet. Such a measurement method, in my
> opinion, is an active method according to RFC 7799. Do you agree?
> 
> TG2> Correct. It is active because packets are originated and reflected
> TG2> at the OAM node with STAMP.
> 
> Hence my first question:
> Are these performance metrics produced using only RFC9197-based manner
> or also combining, for example, STAMP and IOAM?
> 
> TG2> No. Section 4.3.2 "Packet Stream Generation" should be clear with
> TG2> the sentence "The time when the packet is being received at the
> TG2> OAM header encapsulating node" that the OAM packet is not
> TG2> originated. It is passive therefore.
> 
> If the intention to include both approaches, characterization Hybrid
> Type 1 in the name contradicts my conclusion about the combination of
> STAMP and IOAM as an active measurement method.
> 
> TG2> It is not the authors intention.
> 
> My second question is about using Passive in the name. As understand
> naming
> recommendation<https://datatracker.ietf.org/doc/html/rfc8911#name-
> name>, HybridType1_Passive intended to reflect a method that is
> recommended as follows:
> Method:
> One of the methods defined in [RFC7799], such as and not limited to:
> As an alternative to HybridType1_Passive, I propose Hop_by_Hop
> 
> What are your thoughts?
> 
> TG2> Since neither RFC 7799 nor RFC 8911 contain the word "hop" nor
> TG2> "Hop_by_Hop" I object to introduce new terms which are not clearly
> TG2> defined prior. I would like to understand what the objective
> TG2> (judging from prior questions, probably your concern is that it is
> TG2> applicable beyond Hybrid Type 1 Passive, which is not the case) is
> TG2> and from there I can help to make a proposal.
> 
> Taking https://www.rfc-editor.org/rfc/rfc7013.html#section-4.1 as
> naming guidance, taking from that guidance "new Information Elements
> pertaining to a specific protocol should name the protocol in the
> first word in order to ease searching by name" into account,
> considering that the IPFIX metering process can't distinguish between
> wherever the metrics are generated actively or passively, take icmp
> packets captured by the IPFIX process as example, do you agree that
> the following names match the guidance or do you propose a different
> more appropriate name than pathDelay?
> 
> 6.2.  IPFIX Entities
> 
> *   pathDelayMeanDeltaMicroseconds
> pathDelayMinDeltaMicroseconds
> pathDelayMaxDeltaMicroseconds
> pathDelaySumDeltaMicroseconds
> 
> Best wishes
> Thomas
> 
> From: Greg Mirsky
> <[email protected]<mailto:[email protected]>>
> Sent: Saturday, September 6, 2025 8:33 PM
> To: Graf Thomas, SCS-INI-NET-VNC-E2E
> <[email protected]<mailto:[email protected]>>
> Cc: [email protected]<mailto:drafts-expert-review-
> [email protected]>; Michael.Scharf@hs-
> esslingen.de<mailto:[email protected]>;
> [email protected]<mailto:[email protected]>;
> [email protected]<mailto:[email protected]>
> Subject: Re: [OPSAWG]Re: [IANA #1422930] expert review for draft-ietf-
> opsawg-ipfix-on-path-telemetry (performance-metrics)
> 
> Be aware: This is an external email.
> 
> 
> Hi Thomas,
> 
> Thank you for the expedient response. I thought that Passive refers to
> the measurement method, not the method of collecting metrics. If
> Passive in the registry name refers to IPFIX as the performance metric
> collection method, should all metrics collected using IPFIX include
> the Passive reference? Is this naming convention used in the IANA
> Performance Metrics
> registry<https://www.iana.org/assignments/performance-
> metrics/performance-metrics.xhtml>? If performance metrics defined in
> the draft are collected using methods other than IPFIX, e.g., YANG
> notifications, should it be described in the registry as a different
> metric? And as we are discussing naming, according to RFC 7799, the
> Hybrid performance method is a combination of Passive and Active
> measurement methods. IOAM and Alternate Marking are examples of a
> Hybrid measurement method when applied to a data flow. However, when
> IOAM or Alternate Marking is used in combination with a specially
> constructed test packet, e.g., STAMP, it is still characterized as an
> Active measurement method. But that combination can produce
> performance metrics defined in the draft under discussion. That brings
> me to question the use of Hybrid Type 1 in the naming of new entries
> in the IANA Performance Metrics registry. Would both cases of using
> IOAM or Alternate Marking be generalized by replacing HybridType1 with
> another identification, e.g., HopByHop, to signify the collection of
> performance metrics from transit nodes?
> 
> What are your thoughts?
> 
> 
> 
> Regards,
> 
> Greg
> 
> On Sat, Sep 6, 2025 at 1:07 AM
> <[email protected]<mailto:[email protected]>> wrote:
> Dear Greg,
> 
> GIM>> I probably was not clear in my notes. My question is Why Hybrid
> GIM>> Type 1 and Passive are concatenated in IE's name, e.g.,
> GIM>> OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Sum?
> 
> Apologies for not having commented this point.
> OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Sum is the name
> in the performance registry. Not the IE name.
> 
> The name for the performance registry is defined in section 4.1.1.2
> where for IPFIX entities in 6.2
> 
> 4.1.1.2.  Name
> 
> OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Mean
> OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Min
> OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Max
> OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Sum
> 
> 6.2.  IPFIX Entities
> 
> pathDelayMeanDeltaMicroseconds
> pathDelayMinDeltaMicroseconds
> pathDelayMaxDeltaMicroseconds
> pathDelaySumDeltaMicroseconds
> 
> The reason why passive is chosen is because of the document scope:
> Export of Delay Performance Metrics in IPFIX. The IPFIX process
> passively observes IP flows. Section 4.3.2, Packet Stream Generation,
> starts with "The time when the packet is being received at the OAM
> header encapsulating node" therefore.
> 
> Does that clarify your question or do you propose different names?
> Paul as designated IPFIX expert is on C.
> 
> Best wishes
> Thomas
> 
> From: Greg Mirsky
> <[email protected]<mailto:[email protected]>>
> Sent: Saturday, September 6, 2025 2:16 AM
> To: Graf Thomas, SCS-INI-NET-VNC-E2E
> <[email protected]<mailto:[email protected]>>
> Cc: [email protected]<mailto:drafts-expert-review-
> [email protected]>; Michael.Scharf@hs-
> esslingen.de<mailto:[email protected]>;
> [email protected]<mailto:[email protected]>;
> [email protected]<mailto:[email protected]>
> Subject: Re: [OPSAWG]Re: [IANA #1422930] expert review for draft-ietf-
> opsawg-ipfix-on-path-telemetry (performance-metrics)
> 
> Be aware: This is an external email.
> 
> Hi, Thomas and the authors,
> thank you for your careful consideration of my comments. I appreciate
> updates that address them improving the document. Please find my
> follow-up notes below tagged GIM>>.
> 
> Regards,
> Greg
> 
> On Thu, Sep 4, 2025 at 10:16 PM
> <[email protected]<mailto:[email protected]>> wrote:
> 
> Dear David and Greg,
> 
> 
> 
> On behalf of the authors, thank you very much for your detailed review
> and comments.
> 
> 
> 
> We addressed your feedback together with Tim's, Mike's, Med's, Deb's,
> Éric's, Gunter's and Gorry's as following
> 
> https://author-tools.ietf.org/diff?doc_1=draft-ietf-opsawg-ipfix-on-
> path-telemetry-20&url_2=https://raw.githubusercontent.com/network-
> analytics/draft-ietf-opsawg-ipfix-on-path-
> telemetry/refs/heads/main/draft-ietf-opsawg-ipfix-on-path-telemetry-
> 21.txt
> 
> 
> 
> GM> Characterization if Passport and Postcard modes in the Introduction
> GM> is not consistent with RFC 9232 where the passport mode is referred
> GM> to IOAM as defined in RFC 9127, while postcard mode - to RFC 9326.
> GM> According to RFC 9232, the passport mode is when telemetry
> GM> information is collected along the path and transported in the
> GM> trigger packet, while postcard mode - such information is collected
> GM> and transported from each traversed node by some mechanism, e.g.,
> GM> over the management plane.
> 
> 
> 
> Your description on Passport and Postcard mode is correct. Regarding
> RFC 9232 reference. I believe you are refering to
> https://datatracker.ietf.org/doc/html/rfc9232#appendix-A.3.5. Our
> understanding is that IOAM is one of many implementations of passport
> resp. postcard mode. Your understanding is that IOAM the only
> implementation correct?
> GIM>> The updated terminology, i.e., "OAM header decapsulating node"
> GIM>> and "OAM header transit node", addresses my concern. You may
> GIM>> consider dropping "header" altogether.
> 
> 
> 
> GM> Combining "Hybrid Type I" with "Passive" in reference to
> GM> performance metrics is confusing and inaccurate. RFC 7799 defines
> GM> hybrid measurement methods as a combination of the elements of
> GM> passive and active measurement methods. Furthermore, RFC 7799
> GM> identifies two types of hybrid measurement methods - Type I (IOAM
> GM> and Alternate Marking are examples of it) and Type II. There's no
> GM> mention of Hybrid Type I Passive in RFC 7799.
> 
> 
> 
> This has been addressed by refering now to two terms "Passive" and
> "Hybrid Type I" to section 3.7 and 3.8 of RFC 7799 separately.
> GIM>> I probably was not clear in my notes. My question is Why Hybrid
> GIM>> Type 1 and Passive are concatenated in IE's name, e.g.,
> GIM>> OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Sum?
> 
> 
> 
> GM> Another concern with the naming new IPFIX IEs is reference to IP in
> GM> "HybridType1_Passive_IP". Is it to signify that the IEs are
> GM> applicable only to delay measurement of the IP flows? But can they
> GM> be used to export delay metrics of, for example, an MPLS flow?
> 
> 
> 
> The document scope is IP flow. Therefore IP is used in the naming.
> 
> 
> 
> GM> Some key elements used in the document, e.g., "OAM node" and
> GM> "Collector", are underdefined.
> 
> 
> 
> "Collector" has been used from RFC 7011 and is now defined as well.
> "OAM node" has been replaced with "OAM header encapsulating node",
> "OAM header transit node" and "OAM header decapsulating node" which
> are defined in the document.
> GIM>> Thank you.
> 
> 
> 
> GM> I consider the content of Section 3.2.2 Packet Stream Generation
> GM> essential and that the reader must understand any document
> GM> referenced in the section. Hence, I believe that references to [I-
> GM> D.zhou-ippm-enhanced-alternate-marking]  and [I-D.fz-spring-srv6-
> GM> alt-mark] must be normative, if the Alternate Marking method is in
> GM> the scope of the document.
> 
> 
> 
> I agree that the "Packet Stream Generation" section contains two
> normative sentences:
> 
> 
> 
> The time when the packet is being received at the OAM header
> 
> encapsulating node.  The timestamp format depends on On-Path
> 
> Telemetry implementation.
> 
> 
> 
> However the sentences describing possible implementations such as IOAM
> or Enhanced Alternate Marking are not normative since in the preceding
> section, "IP One-Way Delay Hybrid Type I Passive Performance Metrics",
> a generic metric definition is defined as per RFC 8911.
> 
> 
> 
> I hope this addresses your comments. Looking forward to your review.
> 
> 
> 
> Best wishes
> 
> Thomas
> 
> 
> From: Greg Mirsky
> <[email protected]<mailto:[email protected]>>
> Sent: Friday, August 1, 2025 10:52 PM
> To: [email protected]<mailto:drafts-expert-review-
> [email protected]>
> Cc: [email protected]<mailto:Michael.Scharf@hs-
> esslingen.de>; [email protected]<mailto:[email protected]>
> Subject: [OPSAWG]Re: [IANA #1422930] expert review for draft-ietf-
> opsawg-ipfix-on-path-telemetry (performance-metrics)
> 
> Hi David,
> thank you for your kind consideration. Iread the latest version of the
> draft and found that my concern about the naming new IEs ( see
> comments from 10,
> 2024<https://mailarchive.ietf.org/arch/msg/opsawg/kbNvNZgNfDThtg3ZZj9q0Jawx80/>)
> is not addressed, along with concerns with using undefined entities
> like "OAM node" and "Collector". Below, please find my comments to the
> draft-ietf-opsawg-ipfix-on-path-telemetry-20:
> 
> *   Characterization if Passport and Postcard modes in the
> Introduction is not consistent with RFC 9232 where the passport mode
> is referred to IOAM as defined in RFC 9127, while postcard mode - to
> RFC 9326. According to RFC 9232, the passport mode is when telemetry
> information is collected along the path and transported in the trigger
> packet, while postcard mode - such information is collected and
> transported from each traversed node by some mechanism, e.g., over the
> management plane.
> *   Combining "Hybrid Type I" with "Passive" in reference to
> performance metrics is confusing and inaccurate. RFC 7799 defines
> hybrid measurement methods as a combination of the elements of passive
> and active measurement methods. Furthermore, RFC 7799 identifies two
> types of hybrid measurement methods - Type I (IOAM and Alternate
> Marking are examples of it) and Type II. There's no mention of Hybrid
> Type I Passive in RFC 7799.
> *   Another concern with the naming new IPFIX IEs is reference to IP
> in "HybridType1_Passive_IP". Is it to signify that the IEs are
> applicable only to delay measurement of the IP flows? But can they be
> used to export delay metrics of, for example, an MPLS flow?
> *   Some key elements used in the document, e.g., "OAM node" and
> "Collector", are underdefined.
> *   I consider the content of Section 3.2.2 Packet Stream Generation
> essential and that the reader must understand any document referenced
> in the section. Hence, I believe that references to [I-D.zhou-ippm-
> enhanced-alternate-marking]  and [I-D.fz-spring-srv6-alt-mark] must be
> normative, if the Alternate Marking method is in the scope of the
> document.
> I hope that my comments are helpful.
> 
> Regards,
> Greg
> 
> On Tue, Jul 29, 2025 at 1:46 PM David Dong via RT <drafts-expert-
> [email protected]<mailto:[email protected]>>
> wrote:
> Hi Greg,
> 
> That will be fine, thank you!
> 
> Best regards,
> 
> David Dong
> IANA Services Sr. Specialist
> 
> On Tue Jul 29 20:44:30 2025,
> [email protected]<mailto:[email protected]> wrote:
> > Hi David,
> > my apologies for the belated response and missing the deadline. I can
> > review the current version by August 1st. Please let me know if that
> > is
> > acceptable to you.
> >
> > Regards,
> > Greg
> >
> > On Tue, Jul 29, 2025 at 12:39 PM David Dong via RT <
> > [email protected]<mailto:drafts-expert-review-
> > [email protected]>> wrote:
> >
> > > Hi Greg,
> > >
> > > Just a ping on this one if you're available to take another look at
> > > this
> > > document.
> > >
> > > Thank you!
> > >
> > > Best regards,
> > >
> > > David Dong
> > > IANA Services Sr. Specialist
> > >
> > > On Wed Jul 16 20:58:45 2025, Michael.Scharf@hs-
> > > esslingen.de<mailto:[email protected]> wrote:
> > > > Hi David,
> > > >
> > > > As Greg has already reviewed earlier versions of this document, I
> > > > believe that he is in a better position to review this document.
> > > >
> > > > If Greg is not available, I'd have a look myself.
> > > >
> > > > I have not followed this document in detail so far. As far as I
> > > > can
> > > > see, there has been a OPSAWG list discussion regarding IANA in
> > > > the
> > > > past. For what it is worth, I back some of the questions raised
> > > > by
> > > > Greg in his past e-mail
> > > > (
> > > https://mailarchive.ietf.org/arch/msg/opsawg/kbNvNZgNfDThtg3ZZj9q0Jawx80/
> > > ).
> > > > And at least in the list archive it is not clear how all of them
> > > > have
> > > > been resolved, as there is only one follow-up posting. For
> > > > instance,
> > > > RFC 7799 Section 3.8 doesn't really define a combination of
> > > > "Hybrid I"
> > > > and "Passive", as far as I read the text of RFC 7799. But Greg
> > > > has
> > > > probably more context regarding that discussion.
> > > >
> > > > Best regards
> > > >
> > > > Michael
> > > >
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: David Dong via RT <drafts-expert-review-
> > > > > [email protected]<mailto:[email protected]>>
> > > > > Sent: Tuesday, July 15, 2025 12:01 AM
> > > > > Cc: [email protected]<mailto:[email protected]>;
> > > > > Scharf, Michael <Michael.Scharf@hs-
> <mailto:Michael.Scharf@hs-%0b>> > > >
> esslingen.de<http://esslingen.de/>>;
> [email protected]<mailto:[email protected]>
> > > > > Subject: [IANA #1422930] expert review for draft-ietf-opsawg-
> > > > > ipfix-
> > > > > on-path-
> > > > > telemetry (performance-metrics)
> > > > >
> > > > > Dear Greg Mirsky, Michael Scharf (cc: opsawg wg),
> > > > >
> > > > > As the designated experts for the Performance Metrics Registry,
> > > > > can
> > > > > you
> > > > > review the proposed registrations in draft-ietf-opsawg-ipfix-
> > > > > on-path-
> > > > > telemetry-19 for us? Please see
> > > > >
> > > > > https://datatracker.ietf.org/doc/draft-ietf-opsawg-ipfix-on-
> > > > > path-
> > > > > telemetry/
> > > > >
> > > > > The due date is July 28th.
> > > > >
> > > > > If this is OK, when the IESG approves the document for
> > > > > publication,
> > > > > we'll make
> > > > > the registration at:
> > > > >
> > > > > https://www.iana.org/assignments/performance-metrics/
> > > > >
> > > > > Unless you ask us to wait for the other reviewer, we’ll act on
> > > > > the
> > > > > first response
> > > > > we receive.
> > > > >
> > > > > With thanks,
> > > > >
> > > > > David Dong
> > > > > IANA Services Sr. Specialist
> > >
> > >

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