Shepherd writeup

As required by RFC 4858, this is the current template for the Document 
Shepherd Write-Up. Changes are expected over time. 

This version is dated 1 November 2019.

Data Fields for In-situ OAM

Note: This write-up may not be final: see Shepherd's comments at the end.
Date May 30, 2020

(1) What type of RFC is being requested (BCP, Proposed Standard, Internet Standard, Informational, Experimental, or Historic)? Why is this the proper type of RFC? Is this type of RFC indicated in the title page header? 

Standards Track, appropriate as a reference for additional RFCs that specify encapsulations in a variety of protocols, such as Segment Routing, Geneve, or IPv6.
Standards Track is indicated on the title page 
>>>>>>(but the Datatracker needs update).

(2) The IESG approval announcement includes a Document Announcement Write-Up. Please provide such a Document Announcement Write-Up. Recent examples can be found in the "Action" announcements for approved documents. The approval announcement contains the following sections: 

Technical Summary:

This memo describes a specific type of OAM capability intended to operate within a network domain, and complements traditional measurement tools for connectivity and route discovery (such as ping and traceroute). This form is called In-situ-OAM, and the techniques employed fall in the RFC 7799 category of Hybrid Type I (as a combination of Active measurement using synthetic traffic and pure Passive observations of user traffic, by adding measurement-specific information to user traffic).  Packets with In-situ OAM encapsulation record information as they traverse nodes within a specific network domain. This information includes timestamps, identification of interfaces, and other details that can assist with OAM activities which include new ones, such as proof of transit (exactly which nodes/interfaces were visited). The IOAM encapsulation will be added/removed at domain ingress/egress, may be added to all or a subset of packets, and updated at all or a subset of transit nodes. IOAM Namespaces provide another dimension of flexibility for actions. This memo will be used a as a reference for additional RFCs that specify encapsulations in a variety of protocols, such as Segment Routing, Geneve, or IPv6.

Working Group Summary:

Was there anything in WG process that is worth noting? For example, was there controversy about particular points or were there decisions where the consensus was particularly rough? 

This work topic & proposal was bounced-around a bit before finding an appropriate home in Transport Area and IPPM WG.

Many of the details of IOAM data fields and operations were discussed at length on e-mail and debated at side meetings. Further the development used GitHub's capabilities to track issues and the discussion to resolve each item.

Note that at the present time (May 29), 2 relevant PRs are open:

Document Quality:

Are there existing implementations of the protocol? Have a significant number of vendors indicated their plan to implement the specification? Are there any reviewers that merit special mention as having done a thorough review, e.g., one that resulted in important changes or a conclusion that the document had no substantive issues? If there was a MIB Doctor, YANG Doctor, Media Type or other expert review, what was its course (briefly)? In the case of a Media Type review, on what date was the request posted? 


Who is the Document Shepherd?          Al Morton
Who is the Responsible Area Director?  Martin Duke

(3) Briefly describe the review of this document that was performed by the Document Shepherd. If this version of the document is not ready for publication, please explain why the document is being forwarded to the IESG.

The Shepherd has reviewed the present draft, and several previous version dating back to the original proposals. Some of the reviews were prompted by interaction between IOAM capabilities and the IPPM WG Draft on Route Metrics. 

(4) Does the document Shepherd have any concerns about the depth or breadth of the reviews that have been performed? 

No concerns, the review in total has been extensive, with many detailed items precipitating active discussions. 

(5) Do portions of the document need review from a particular or from broader perspective, e.g., security, operational complexity, AAA, DNS, DHCP, XML, or internationalization? If so, describe the review that took place. 

The usual Directorate Reviews should be sufficient.
OPS should ensure that Shepherd's comments appended to this form have been resolved.

(6) Describe any specific concerns or issues that the Document Shepherd has with this document that the Responsible Area Director and/or the IESG should be aware of? For example, perhaps he or she is uncomfortable with certain parts of the document, or has concerns whether there really is a need for it. In any event, if the WG has discussed those issues and has indicated that it still wishes to advance the document, detail those concerns here. 

No concerns. There has been plenty of time for concerns to be expressed and for consensus to emerge (since July 2016).

(7) Has each author confirmed that any and all appropriate IPR disclosures required for full conformance with the provisions of BCP 78 and BCP 79 have already been filed. If not, explain why?

 F. Brockners
 S. Bhandari
 C. Pignataro
 H. Gredler
 J. Leddy
 S. Youell
 T. Mizrahi
 D. Mozes
 P. Lapukhov
 R. Chang
 D. Bernier
 J. Lemon

(8) Has an IPR disclosure been filed that references this document? If so, summarize any WG discussion and conclusion regarding the IPR disclosures.

There is one IPR Disclosure:

There appears to have been no discussion of this Disclosure when it appeared on the ippm-list (20 May 2019) to the present.

(9) How solid is the WG consensus behind this document? Does it represent the strong concurrence of a few individuals, with others being silent, or does the WG as a whole understand and agree with it? 

Consensus in the end appears strong, after considerable review and negotiation.

(10) Has anyone threatened an appeal or otherwise indicated extreme discontent? If so, please summarise the areas of conflict in separate email messages to the Responsible Area Director. (It should be in a separate email because this questionnaire is publicly available.) 

No Appeals threatened.

(11) Identify any ID nits the Document Shepherd has found in this document. (See and the Internet-Drafts Checklist). Boilerplate checks are not enough; this check needs to be thorough. 

No problems with nits, several comments on version 09 to check:

  == Unused Reference: 'I-D.lapukhov-dataplane-probe' is defined on line
     1815, but no explicit reference was found in the text

  -- Possible downref: Non-RFC (?) normative reference: ref. 'IEEE1588v2'

  -- Possible downref: Non-RFC (?) normative reference: ref. 'POSIX'

(12) Describe how the document meets any required formal review criteria, such as the MIB Doctor, YANG Doctor, media type, and URI type reviews. 


(13) Have all references within this document been identified as either normative or informative? 


(14) Are there normative references to documents that are not ready for advancement or are otherwise in an unclear state? If such normative references exist, what is the plan for their completion? 

All Normative References are complete/approved.

(15) Are there downward normative references references (see RFC 3967)? If so, list these downward references to support the Area Director in the Last Call procedure. 

Possibly - see item (11) above.

(16) Will publication of this document change the status of any existing RFCs? Are those RFCs listed on the title page header, listed in the abstract, and discussed in the introduction? If the RFCs are not listed in the Abstract and Introduction, explain why, and point to the part of the document where the relationship of this document to the other RFCs is discussed. If this information is not in the document, explain why the WG considers it unnecessary. 

No change of status for other docs.

(17) Describe the Document Shepherd's review of the IANA considerations section, especially with regard to its consistency with the body of the document. Confirm that all protocol extensions that the document makes are associated with the appropriate reservations in IANA registries. Confirm that any referenced IANA registries have been clearly identified. Confirm that newly created IANA registries include a detailed specification of the initial contents for the registry, that allocations procedures for future registrations are defined, and a reasonable name for the new registry has been suggested (see RFC 8126). 

This memo creates a new family of registries, and the initial contents have been carefully provided.

(18) List any new IANA registries that require Expert Review for future allocations. Provide any public guidance that the IESG would find useful in selecting the IANA Experts for these new registries. 

Most of the Registries are RFC Required, however the IOAM Namespace-ID Registry entries will be assigned after Expert Review.

(19) Describe reviews and automated checks performed by the Document Shepherd to validate sections of the document written in a formal language, such as XML code, BNF rules, MIB definitions, YANG modules, etc.

None, NA.

(20) If the document contains a YANG module, has the module been checked with any of the recommended validation tools ( for syntax and formatting validation? If there are any resulting errors or warnings, what is the justification for not fixing them at this time? Does the YANG module comply with the Network Management Datastore Architecture (NMDA) as specified in RFC8342?

None, NA.

Doc Shepherd's Comments:

1. closed PR
Two Comments indicate the value of a Manageability Considerations section while resolving issues in the discussion. However, the -09 version still does not have this section a year later... The important topic discussed was congestion management, but there are no instances of "congest" in the -09 text. 

Section 3, Scope, etc. contains topic:
Deployment domain (or scope) of in-situ OAM deployment:, in which many operational considerations are detailed that could be part of a Manageability Considerations: section.

4.4 Trace Option types
   ...The maximum
   number of hops and the minimum path MTU of the IOAM domain is assumed
   to be known.
What are the consequences when they are not known?
	Looks like the Flag Bit 0 O-bit handles this case for number of hops.
Or, is this knowledge highly likely, and expected to be violated only under the most unexpected conditions (restoration from multiple failures)?
See point below on "minimum path MTU".

      Given that the sender knows the minimum path MTU, the sender MAY
      set the initial value of RemainingLen according to the number of
      node data bytes allowed before exceeding the MTU.
"minimum path MTU" is the smallest Maximum Transmission Unit for all links in a path, or simply the Path MTU, PMTU, right?

4.5 Proof of Transit

Is there a Reference for "Shamir's Secret Sharing Schema (SSSS)" ?
Or, is it a secret?

7.  IANA Considerations
(apologies in advance for a long/recent/good experience with IANA, and the many other folks who try to help)
This section appears to define a set of related registries.
The Hierarchy could be named a bit more efficiently than:

7.1 In-Situ OAM Protocol Parameters Registry (IOAM) Protocol Parameters IANA registry

In-Situ OAM (IOAM) Protocol Parameters Group
    7.1  IOAM Protocol Parameters Registry
	7.2  IOAM Option-Type Registry
	7.3  IOAM Trace-Type Registry