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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.

(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 module for configuring and basic monitoring of the
TACACS+ protocol.  It is intended as a Standards Track document.  This is
clearly indicated in the document and fits with other such documents that
define similar configuration and monitoring modules (i.e., RFC7317, which this
module augments).

(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 document defines a YANG module that augments the System Nanagement data
model with nodes to configure client-sided TACACS+ (akin to the RADIUS config
already in the system module).  Additionally, the module provides some
read-only objects for monitoring the state of the TACACS+ client.

Working Group Summary:

The contention over TACACS+ in general carried over a bit in the initial
development of this document and its module.  To alleviate that, the scope was
reduced to avoid an overall AAA module and instead focus on configuring the
client-side of the TACACS+ protocol specifically.  Towards the end, there was
good feedback on YANG structure, terminology and providing an example to make
the module use clearer.

That said, the ietf-system currently only defines authentication and not
authorization and accounting.  So, while the TACACS+ module allows to specify a
TACACS+ server that can do both authorization and accounting, the configuration
nodes for that are not yet in the ietf-system module.  The intent, as I
understand, is to propose new work to handle those methods in a more general
approach outside the restricted scope of this TACACS+ document.

Document Quality:

The document has undergone various expert-level reviews besides the WG review. 
In particular YANG Doctors and SECDIR have reviewed and said it was ready.  The
comments that arose from those reviews have been addressed in revision -05 of
the document.  Huawei has also implemented this draft in their devices.

The shepherd noticed some other issues in -05 (stemming from the evolution of
the document), and a -06 was published to address them.


Who is the Document Shepherd? Who is the Responsible Area Director?

Joe Clarke is the Document Shepherd and Rob Wilton is the responsible Area

(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.

This document has been reviewed by the WG, the shepherd, Yang Doctors, and

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

The shepherd does not have any concerns.

(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.

Not at this point.

(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?

A call for IPR was done on July 7, 2019 and the authors acknowledged that no
known IPR exists.

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


(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 is believed to be strong on this with no vocal 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.)


(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.

There is one current downref in the document on the Informational
draft-ietf-opsawg-tacacs document.  The history of that document requires it to
be Informational as the intent was to define the TACACS+ protocol as it exists
today.  That said, the desire for this document was to be standards track to
coincide with similar documents that define configuration mechanisms for system

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

The YANG Doctor review found some nits which were discussed on list and
corrected in revision -05 of the document.

(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?

The draft-ietf-ospawg-tacacs document is currently in the final stages of
review, and all other references are already published.

(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

Yes.  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.


(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).

As with other YANG modules, IANA is asked to register the namespace for the
TACACS+ YANG module.

(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.

There are no new registries, just new entries to existing registries.

(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.

This document has undergone IDNITS checks as well as the automated YANG syntax
checks in DataTracker.  All pass.

(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

Yes.  It has been checked, and there are no issues.