A YANG Data Model for the Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD)
draft-ietf-pim-igmp-mld-yang-15

[Ballot comment]
I do have a general concern with the document in relation to its handling of multiple protocol versions. There are features in the yang models that should be conditional but they do not seem to be. Here are some examples.

* The source specific features are to be used with IGMPv3 and MLDv2 and will not work with the earlier versions
* The router alert check is not optional for MLD or IGMPv3, but is required to be disabled for compatibility with earlier versions of IGMP. I would also make this feature conditional on the IGMP version. If not you need to rethink the defaults for this.

I would like to understand the authors' views on how they plan to address the potential consistency issues due to these features being unbound in the model. I would be fine if it is either addressed with yang constructs or with some explanatory text to this point.

[Ballot comment]
Other than my Discuss point (which seems to be resolvable with no
change), basically all I have is editorial nits -- thanks for
the well-written document!

Section 2.1

                                  Even though there is no protocol
  specific notifications are defined in this model, the subscription

nit: s/there is// -- the "are defined in this model" takes care of
the grammatical necessities here.
  and push mechanism defined in [I-D.ietf-netconf-subscribed-
  notifications] and [I-D.ietf-netconf-yang-push] can be used by the
  user to subscribe notifications on the data nodes in this model.

nit: "subscribe to notifications"

  The model contains all basic configuration parameters to operate the
  protocols listed above. Depending on the implementation choices,

nit: "all the basic"

Section 4

    grouping interface-common-config-attributes {
      [...]
      leaf query-interval {
        [...]
        description
          "The Query Interval is the interval between General Queries
            sent by the Querier.In RFC3376, Querier's Query
            Interval(QQI) is represented from the Querier's Query
            Interval Code in query message as follows:

nit: one or two (not zero) spaces after the end of the sentence.
nit: "In RFC3376, the Querier's Query Interval (QQI)"

      leaf exclude-lite {
        if-feature intf-exclude-lite;

side-note: I misparsed this (I think) the first few times I read it,
since "exclude lite" can be taken as an imperative command to not use
the lite version.  But it seems this is really just an ordinary
feature-enablment tag about whether to use the EXCLUDE filtering that
is available in the lite version of the protocol.  I don't know whether
reordering to "lite-exclude" would be a net win or net loss due to
causing some other confusion, though.

    grouping interface-state-attributes-igmp {
      [...]
      list group {
        [...]
        list source {
          [...]
          list host {
    [...]
            leaf host-address {
              type inet:ipv4-address;
              description
                "The IPv6 address of the host.";

nit: "ipv6-address"

    grouping interface-state-group-attributes-igmp-mld {

nit: I thought most of the other shared groupings just didn't use a
suffix, as opposed to using the "-igmp-mld" combined suffix.
(Similarly for interface-state-source-attributes-igmp-mld and
interface-state-host-attributes-igmp-mld, which does cause me to wonder
if I'm not perceiving "most" correctly.)

Section 5

  igmp-mld:global

    This subtree specifies the configuration for the IGMP attributes
    at the global level on an IGMP instance.  Modifying the
    configuration can cause IGMP membership deleted or reconstructed
    on all the interfaces of an IGMP instance.

nit: "to be deleted or reconstructed"  (Similarly for the following
paragraphs.)

The description of the considerations for unauthorized read access are
fairly generic and do not specify specific potential harms, but I will
not insist on any changes here.

[Ballot comment]
(1) I support Ben Kaduk’s DISCUSS about privacy considerations.

(2) Thanks for Section 1.3.  This upfront cross-reference was very helpful!

(3) Section 2.2.
  On the other hand, operational state parameters are not so widely
  designated as features, as there are many cases where the defaulting
  of an operational state parameter would not cause any harm to the
  system, and it is much more likely that an implementation without
  native support for a piece of operational state would be able to
  derive a suitable value for a state variable that is not natively
  supported.

I struggled to understand this very dense single sentence paragraph.
-- What does it mean for “operational state parameters are not so widely designated as features”?
-- What is a “defaulting of an operational state parameter”?

(4) Section 3.  Does the sentence “This model augments the core routing data model specification in [RFC8349]” suggest that this draft should update [RFC8349]?

(5) Reference Nits
** Section 1.  I would have expected a reference to NMDA (i.e., [RFC8342]).  This is done later in the draft but not the first time it is mentioned (here).

** idnits returned the following valid reference issues:

  == Missing Reference: 'I-D.ietf-netconf-yang-push' is mentioned on line
    178, but not defined

  == Missing Reference: 'RFC 8446' is mentioned on line 1910, but not defined

  == Missing Reference: 'RFC8341' is mentioned on line 1912, but not defined

  == Unused Reference: 'RFC5246' is defined on line 2085, but no explicit
    reference was found in the text

  == Unused Reference: 'RFC6536' is defined on line 2099, but no explicit
    reference was found in the text

  == Unused Reference: 'RFC5790' is defined on line 2145, but no explicit
    reference was found in the text

  ** Downref: Normative reference to an Informational RFC: RFC 3569

  ** Obsolete normative reference: RFC 5246 (Obsoleted by RFC 8446)

  ** Obsolete normative reference: RFC 6536 (Obsoleted by RFC 8341)

(6) Editorial Nits

** Section 2.1.  The sentence “Even though there is no protocol specific notifications are defined in this model, the subscription and push mechanism defined in [I-D.ietf-netconf-subscribed-  notifications] and [I-D.ietf-netconf-yang-push]” doesn’t parse.  Likely remove the “are”.

** Section 2.1.  Per the sentence “Depending on the implementation choices, some systems may not allow some of the advanced parameters  configurable”, what is a “advanced parameters configurable”?  I think there is a typo there.

**  Section 2.3.  Per “The current document defines …”, shouldn’t this just be “The document defines …” since when published as an RFC there would be no notion of versioning as suggested by “current”?

** Section 2.3.  s/supports and only supports/only supports/

** Section 4.  Typo.  s/refered/referred/

** Section 4. Missing space.  /Querier.In RFC3376,/Querier. In RFC3376,/

[Ballot comment]
One very minor question about data tree representation:

Should this figure have vertical bars from rw ssm-map down to the plus for rw ssm-map-source-addr?
                +--rw ssm-map*
                |      [ssm-map-source-addr ssm-map-group-policy]
                |      {intf-ssm-map}?
                |  +--rw ssm-map-source-addr    ssm-map-ipv4-addr-type
                |  +--rw ssm-map-group-policy    string
                +--rw static-group* [group-addr source-addr]
                |      {intf-static-group}?
                |  +--rw group-addr
                |  |      rt-types:ipv4-multicast-group-address
                |  +--rw source-addr
                |          rt-types:ipv4-multicast-source-address

Thus making the unattached brances being attached?

[Ballot discuss]
I agree with Mirja that reiterating the privacy considerations of
explicit tracking of group membership (with pointer to the relevant
IGMP/MLD protocol documents) would be worthwhile.
Normally I would leave this as a Comment on the assumption that the
privacy considerations are already documented in the protocol
specification that documents explicit tracking, but I could not find
such a document (with privacy considerations listed) in a quick search;
I found RFC 6636 and draft-ietf-pim-explicit-tracking but probably
missed a few others.

Let's talk about what the current state actually is, and where it's best
to document the privacy considerations (which is not necessarily this
document, a priori).

[Ballot comment]
Other than my Discuss point, basically all I have is editorial nits -- thanks for
the well-written document!

Section 2.1

                                  Even though there is no protocol
  specific notifications are defined in this model, the subscription

nit: s/there is// -- the "are defined in this model" takes care of
the grammatical necessities here.
  and push mechanism defined in [I-D.ietf-netconf-subscribed-
  notifications] and [I-D.ietf-netconf-yang-push] can be used by the
  user to subscribe notifications on the data nodes in this model.

nit: "subscribe to notifications"

  The model contains all basic configuration parameters to operate the
  protocols listed above. Depending on the implementation choices,

nit: "all the basic"

Section 4

    grouping interface-common-config-attributes {
      [...]
      leaf query-interval {
        [...]
        description
          "The Query Interval is the interval between General Queries
            sent by the Querier.In RFC3376, Querier's Query
            Interval(QQI) is represented from the Querier's Query
            Interval Code in query message as follows:

nit: one or two (not zero) spaces after the end of the sentence.
nit: "In RFC3376, the Querier's Query Interval (QQI)"

      leaf exclude-lite {
        if-feature intf-exclude-lite;

side-note: I misparsed this (I think) the first few times I read it,
since "exclude lite" can be taken as an imperative command to not use
the lite version.  But it seems this is really just an ordinary
feature-enablment tag about whether to use the EXCLUDE filtering that
is available in the lite version of the protocol.  I don't know whether
reordering to "lite-exclude" would be a net win or net loss due to
causing some other confusion, though.

    grouping interface-state-attributes-igmp {
      [...]
      list group {
        [...]
        list source {
          [...]
          list host {
    [...]
            leaf host-address {
              type inet:ipv4-address;
              description
                "The IPv6 address of the host.";

nit: "ipv6-address"

    grouping interface-state-group-attributes-igmp-mld {

nit: I thought most of the other shared groupings just didn't use a
suffix, as opposed to using the "-igmp-mld" combined suffix.
(Similarly for interface-state-source-attributes-igmp-mld and
interface-state-host-attributes-igmp-mld, which does cause me to wonder
if I'm not perceiving "most" correctly.)

Section 5

  igmp-mld:global

    This subtree specifies the configuration for the IGMP attributes
    at the global level on an IGMP instance.  Modifying the
    configuration can cause IGMP membership deleted or reconstructed
    on all the interfaces of an IGMP instance.

nit: "to be deleted or reconstructed"  (Similarly for the following
paragraphs.)

The description of the considerations for unauthorized read access are
fairly generic and do not specify specific potential harms, but I will
not insist on any changes here.

[Ballot comment]
Two quick questions:

1) Not sure about the current practice about YANG models but shouldn’t this document eventually update RFC8349?

2) Also maybe it would make sense to discuss the sensitivity of explicit-tracking separately in the security consideration section?

[Ballot comment]
Two quick questions:

1) Not sure about the current practice about YANG models but shouldn’t this document eventually update RFC8349?

2) Also maybe it would make sense to discuss the sensitivity of explicit-tracking separately in thee security consideration section?

[Ballot comment]
Thanks for the work everyone has put into this document.

I only have a couple of comments (but one important one about the 2 branches) and a couple of nits.

== COMMENTS ==

-- Section 2.1.1 and section 2.1.2 --

Those sections are about configuration parameters not covered at global or interface level. But, what about operational states, can the reader assume that they are all covered by this document ? It is really unclear.

-- Section 2.3 --

As I am not a multicast expert, I did not put a DISCUSS on this one. But, are MLD and IGMP so different? Why having TWO different branches for each address family... For SNMP, RFC 4292/4293 was made protocol version independent which is a big plus IMHO for operations. In any case, there should be more explanations why there are two branches than the one paragraph/two sentences in section 2.3.
Moreover, it seems that the two schema branches are quite similar so having one protocol version independent branch appears to be doable.


== NITS ==

-- Section 1 --

Add a reference to NMDA (expanding the acronym is not really sufficient, state RFC 8342) ?

Expand CLI even if well-known.

(Via drafts-lastcall@iana.org): IESG/Authors/WG Chairs:

The IANA Functions Operator has completed its review of draft-ietf-pim-igmp-mld-yang-10. If any part of this review is inaccurate, please let us know.

The IANA Services Operator understands that, upon approval of this document, there are two actions which we must complete.

First, in the ns registry on the IETF XML Registry page located at:

https://www.iana.org/assignments/xml-registry/

a single, new namespace will be registered as follows:

ID: yang:ietf-igmp-mld
URI: urn:ietf:params:xml:ns:yang:ietf-igmp-mld
Filename: [ TBD-at-Registration ]
Reference: [ RFC-to-be ]

As this document requests registrations in a Specification Required (see RFC 8126) registry, we will initiate the required Expert Review via a separate request. Expert review will need to be completed before your document can be approved for publication as an RFC.

Second, in the YANG Module Names registry on the YANG Parameters registry page located at:

https://www.iana.org/assignments/yang-parameters/

a single, new YANG module will be registered as follows:

Name: ietf-igmp-mld
File: [ TBD-at-Registration ]
Maintained by IANA: N
Namespace: urn:ietf:params:xml:ns:yang:ietf-igmp-mld
Prefix: igmp-mld
Module:
Reference: [ RFC-to-be ]

While the YANG module name will be registered after the IESG approves the document, the YANG module file will be posted after the RFC Editor notifies us that the document has been published.

The IANA Services Operator understands that these are the only actions required to be completed upon approval of this document.

Note:  The actions requested in this document will not be completed until the document has been approved for publication as an RFC. This message is meant only to confirm the list of actions that will be performed.

Thank you,

Sabrina Tanamal
Senior IANA Services Specialist

The following Last Call announcement was sent out (ends 2019-02-08):

From: The IESG
To: IETF-Announce
CC: draft-ietf-pim-igmp-mld-yang@ietf.org, stig@venaas.com, pim-chairs@ietf.org, aretana.ietf@gmail.com, Stig Venaas , pim@ietf.org
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (A YANG data model for Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD)) to Proposed Standard


The IESG has received a request from the Protocols for IP Multicast WG (pim)
to consider the following document: - 'A YANG data model for Internet Group
Management Protocol (IGMP) and
  Multicast Listener Discovery (MLD)'
  as Proposed Standard

The IESG plans to make a decision in the next few weeks, and solicits final
comments on this action. Please send substantive comments to the
ietf@ietf.org mailing lists by 2019-02-08. Exceptionally, comments may be
sent to iesg@ietf.org instead. In either case, please retain the beginning of
the Subject line to allow automated sorting.

Abstract


  This document defines a YANG data model that can be used to
  configure and manage Internet Group Management Protocol (IGMP) and
  Multicast Listener Discovery (MLD) devices.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-pim-igmp-mld-yang/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-pim-igmp-mld-yang/ballot/


No IPR declarations have been submitted directly on this I-D.

The draft has been updated to solve the DownRef issues...but there is an outstanding issue from the YANG Drs.  The conversation is ongoing, so I'm waiting for that to settle before starting the IETF LC.

=== AD Review of draft-ietf-pim-igmp-mld-yang-06 ===
https://mailarchive.ietf.org/arch/msg/pim/30skJ_rUg5sYec2OHi4pWJhA2cc/?qid=d4710ae3d9f7780541784eb5bf84bad0

Dear authors:

I just finished reviewing this document.

I have some comments (below) that I need addressed before we can start the
IETF Last Call, and another YANG Dr review.

Thanks!

Alvaro.


M1. It looks like the document doesn't follow all the recommendations from
rfc6087bis, specifically related to the Security Considerations [1] and the
Tree Diagram, where we need something similar to [2].


M2. References:

M2.1. Please take a look at the Nits [3], as there are several out of date
and unused references.

M2.2. In general, we don't need to reference both the current a bis
versions; rfc8022/rfc8022bis, for example.

M2.3. There's no reference to or mention of
draft-ietf-netmod-revised-datastores, which may be a better reference than
I-D.dsdt-nmda-guidelines.

M2.4. Some of the references (rfc7223bis, for example) are not formatted
correctly.

M2.5. The references to IGMP/MLD should be Normative: "The model covers
IGMPv1 [RFC1112], IGMPv2 [RFC2236], IGMPv3 [RFC3376] and MLDv1 [RFC2710],
MLDv2 [RFC3810]."...and rfc5790.


[1] https://tools.ietf.org/html/draft-ietf-netmod-rfc6087bis-16#section-3.7.1
[2] https://tools.ietf.org/html/draft-ietf-netmod-rfc7223bis-02#section-1.3
[3] https://tools.ietf.org/idnits?url=https://tools.ietf.org/id/draft-ietf-pim-igmp-mld-yang-06.txt

(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?

Proposed Standard. YANG model for a standards track protocol. The type is indicated.

(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

The document defines a YANG data model that can be used to configure and manage Internet Group Management Protocol (IGMP) and Multicast Listener Discovery (MLD) devices.

Working Group Summary

The draft has authors from five different vendors and has been extensively discussed by a multicast YANG design team formed by the working group. More than five implementations were considered to come up with a common model. There were only two responses to the working last call, both supporting the document, but given that five different vendors have been involved and the document has been thoroughly reviewed by the design team, we believe this is sufficient.

Document Quality

There are no known implementations, but vendors have implemented pim YANG models that have some overlap with this model. Five vendors have been working on this model, but we do not know what their implementation plans might be. In addition to thorough review within the design team, the shepherd and at least one other working group participant has reviewed the document. It has also been reviewed by a YANG doctor. Since the YANG doctor review, the document has been changed to support NMDA. A new review should be done to ensure there are no issues.

Personnel

Document Shepherd Stig Venaas
Responsible AD Alvaro Retana

(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 reviewed the document twice, once after adoption, and again as part of working group last call. No major issues found. The issues were addressed.

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

No.

(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.

YANG doctor review was done previously, but should be done again of the latest revision.

(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.

(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.

All authors have stated that they are not aware of any IPR.

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

No

(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? 

It is strong concurrence by the authors and a few other individuals. A handful of people supported going to working group last call, but only two people apart from the five authors have actively supported the document. The rest of the group is silent, but it is difficult to get the majority of the group to review YANG models.

(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

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

There are only minor issues. Mostly about unused or missing references, these are trivial to fix. One concern is a normative downward references.

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

The YANG modules validate. A YANG doctor has reviewed a previous version. We would like a new review.

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

Yes

(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?

There are normative references to the following drafts. Also two of them are informational.

draft-dsdt-nmda-guidelines
draft-bjorklund-netmod-rfc7223bis
draft-bjorklund-netmod-rfc7277bis
draft-ietf-netmod-rfc6087bis
draft-acee-netmod-rfc8022bis

(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.

There are downward normative references to
draft-dsdt-nmda-guidelines
draft-ietf-netmod-rfc6087bis

(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

(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 5226).

The document needs a new URI in the IETF XML registry and an update in the YANG Module Names registry. No new registries.

(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.

None.

(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, etc.

The YANG modules validate.