A YANG Module for Network Address Translation (NAT) and Network Prefix Translation (NPT)
draft-ietf-opsawg-nat-yang-17

[Ballot comment]
Thanks for the easy-to-read document!  I just have a few comments and potential nits
I noticed.

It was somewhat interesting to me that basically everything is config rw, including ports and
addresses that would normally be assigned internally by the NAT, but I don't see this as
problematic.

Section 2.1

                              Considerations about instructing explicit
  dynamic means (e.g., [RFC6887], [RFC6736], or [RFC8045]) are out of
  scope.  [...]

I'm having trouble parsing this; is it maybe "instructing by explicit
dynamic means" or "explicit dynamic mappings"?

Section 3

What's the relationship between hold-down-timeout and hold-down-max -- that
is, if the maximum number of ports in the pool gets hit, to the oldest
ports in the pool get ejected even if they haven't timed out, or what
happens?

I don't expect this to need to be in the document, but I'm curious what the
use case for the all-algs-enable leaf is.

I may be confused, but is the ordering relationship between low-threshold
and high-threshold correct?  From the description it would seem like we
need low < high, but I'm reading the text as requiring low >= high.
Also, the error-message for that "must" stanza talks about port numbers,
not percentage thresholds.

        container connection-limits {
          [...]
          list limit-per-protocol {
            [...]
            leaf limit {
              type uint32;
              description
                "Rate-limit the number of protocol-specific mappings
                and sessions per instance.";

This is a maximum, not a rate-limit, I think?

Section A.6

  EAMs may be enabled jointly with statefull NAT64.  This example shows
  a NAT64 function that supports static mappings:

nit: "stateful"

[Ballot comment]
Thanks for addressing my discuss well and quickly! Also thanks for the other changes to further consider other protocols such as DCCP and SCTP!

[Ballot discuss]
Thanks for a well-written document and also for considering other protocols like SCTP. I've put in a discuss because I would really like have a quick discussion here to double-check that we do the right thing, however, it might well be that we can resolve this discuss without any changes. My question is: given the model is designed to be generic enough to incorporate other transport protocols, I'm wondering if it would be possible to also define the timers you have there in a more generic way such that they can be re-used for other protocols (maybe just changing the name and adding some explanation text).

As a side node: I myself have been working on a model for a protocol-independent state machine a bit (see draft-trammell-plus-statefulness; now expired); maybe that's a helpful reference to have a quick look at…

[Ballot discuss]
Thanks for a well-written document and also for considering other protocols like SCTP. I've put in a discuss because I would really have a quick discussion here and  double-check that we do the right thing, however, it might well be that we can resolve this discuss without any changes. My question is: given the model is designed to be generic enough to incorporate other transport protocols, I'm wondering if it would be possible to also define the timers you have there in a more generic way such that they can be reused for other protocols (maybe just changing the name and adding some explanation text).

As a side node: I myself have been working on a model for a protocol-independent state machine a bit (see draft-trammell-plus-statefulness; now expired); maybe that's a helpful reference to have a quick look at…

[Ballot discuss]
Thanks for a well-written document and also for considering other protocols like SCTP. I've put in a discuss beacuse I would really have a quick discussion here and  double-check that we do the right thing, however, it might well be that we can resolve this discuss without any changes. My question is: given the model is designed to be generic enough to incoperate other transport protocols, I'm wondering if it would be possible to also define the timers you have there in a more generic way such that they can be reused for other protocols (maybe just changing the name and adding some explanation text).

As a side node: I myself have been working on a model for a protocol-independent state machine a bit (see draft-trammell-plus-statefulness; now expired); maybe that's a helpful reference...

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

The IANA Functions Operator has completed its review of draft-ietf-opsawg-nat-yang-14. If any part of this review is inaccurate, please let us know.

The IANA Services Operator has a question about one of the actions requested in the IANA Considerations section of this document.

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

As this document requests registrations in an 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-nat
File: [ TBD-at-Registration ]
Maintained by IANA?
Namespace: urn:ietf:params:xml:ns:yang:ietf-nat
Prefix: nat
Module:
Reference: [ RFC-to-be ]

IANA Question --> What should be the entry for the registry value "Maintained by IANA?" for this new YANG module?

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 2018-06-28):

From: The IESG
To: IETF-Announce
CC: ibagdona@gmail.com, jclarke@cisco.com, draft-ietf-opsawg-nat-yang@ietf.org, opsawg-chairs@ietf.org, Joe Clarke , opsawg@ietf.org
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (A YANG Module for Network Address Translation (NAT) and Network Prefix Translation (NPT)) to Proposed Standard


The IESG has received a request from the Operations and Management Area
Working Group WG (opsawg) to consider the following document: - 'A YANG
Module for Network Address Translation (NAT) and Network Prefix
  Translation (NPT)'
  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 2018-06-28. 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


  For the sake of network automation and the need for programming
  Network Address Translation (NAT) function in particular, a data
  model for configuring and managing the NAT is essential.  This
  document defines a YANG module for the NAT function.

  Network Address Translation from IPv4 to IPv4 (NAT44), Network
  Address and Protocol Translation from IPv6 Clients to IPv4 Servers
  (NAT64), Customer-side transLATor (CLAT), Stateless IP/ICMP
  Translation (SIIT), Explicit Address Mappings for Stateless IP/ICMP
  Translation (SIIT EAM), IPv6 Network Prefix Translation (NPTv6), and
  Destination NAT are covered in this document.

Editorial Note (To be removed by RFC Editor)

  Please update these statements with the RFC number to be assigned to
  this document:

      "This version of this YANG module is part of RFC XXXX;"

      "RFC XXXX: A YANG Module for Network Address Translation (NAT) and
      Network Prefix Translation (NPT)"

      "reference: RFC XXXX"

  Please update the "revision" date of the YANG module.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-opsawg-nat-yang/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-opsawg-nat-yang/ballot/


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


The document contains these normative downward references.
See RFC 3967 for additional information:
    rfc6296: IPv6-to-IPv6 Network Prefix Translation (Experimental - IETF stream)
    rfc6877: 464XLAT: Combination of Stateful and Stateless Translation (Informational - IETF stream)

(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?

This document defines a YANG model for use with Network Address Translation.  It is intended to be a Standard.  The document takes care to cover configuration and operational data monitoring for a variety of standards-based NAT flavors, and thus a standards track document is appropriate.  The standards track is noted in the header of the document.

(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

  For the sake of network automation and the need for programming
  Network Address Translation (NAT) function in particular, a data
  model for configuring and managing the NAT is essential.  This
  document defines a YANG module for the NAT function.

  NAT44, Network Address and Protocol Translation from IPv6 Clients to
  IPv4 Servers (NAT64), Customer-side transLATor (CLAT), Stateless IP/
  ICMP Translation (SIIT), Explicit Address Mappings for Stateless IP/
  ICMP Translation (SIIT EAM), IPv6 Network Prefix Translation (NPTv6),
  and Destination NAT are covered in this document.

Working Group Summary

This document proceded quickly through opsawg as the working group agreed that this work is relevant and the authors addressed feedback in short order.  This feedback included input from vendors as well as operators.

Of note, part of the GENART review for this document pointed out that NPT66, for which this document's YANG model also covers, is experimental and that perhaps that part should be broken out into its own module.  The ADs felt that this one piece did not warrant a separate module.  That decision was accepted by the reporter (Tim Chown), the chairs, and the authors.

Document Quality

This document is well-written and has gone through a number of working group and external reviews.  External reviews include GENART, YANG doctors, RTGDIR, and OPSDIR.  All feedback was incorporated.

The YANG module itself validates without any warnings.

Juniper, Cisco, and Huawei all have co-authors on this document (with Orange), and all three have plans to implement the YANG module.

Personnel

Document shepherd is Joe Clarke, and the responsible AD is Warren Kumari.

(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.

I have read this document and have provided feedback on previous revisions to the authors.  I feel this document is ready for publication.


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

No, I do not.


(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.

All directorates except security returned a review of this.  Some additional attention from Security would be good, but I do not have any overt concerns.

(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.

I have not additional 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.

Yes.  All authors replied that there is no known IPR.  These responses can be found in the archives of the opsawg list.

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

There was no IPR, and a disclosure was not filed.

(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 was strong with no vocalized dissension. 

(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.)

Not to my knowledge.

(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.

The document makes normative references to RFC 6877 (464XLAT) and RFC 6296 (NPTv6) as it provides support for configuring and monitoring these protocols.  Within this scope, it seems the normative references are correct.

Note: the IP address warnings in IDNITS are due to references to IP address ranges used by certain types of NAT.  These are not examples

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

This document was reviewed by YANG Doctors, and all of the feedback was incorporated into fixes.  These can be seen in https://tools.ietf.org/rfcdiff?url2=draft-ietf-opsawg-nat-yang-07.txt .

(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?

See above where normative references are used for informative and experimental documents due to the coverage of the protocols in those documents.  There is one informative reference to a draft in progress (draft-ietf-softwire-dslite-yang).

(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.

Yes.  See 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, it will not.


(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).

This document does not define any new IANA registries, but it does request the following URI:

URI: urn:ietf:params:xml:ns:yang:ietf-nat

And namespace:

namespace: urn:ietf:params:xml:ns:yang:ietf-nat

These are in support of the YANG module defined therein.

(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.

This document has passed the automated YANG check, which includes a number of validators.