IS-IS Flooding Scope Link State PDUs (LSPs)
RFC 7356

Received changes through RFC Editor sync (changed abstract to 'Intermediate System to Intermediate System (IS-IS) provides efficient and reliable flooding of information to its peers; however, the current flooding scopes are limited to either area scope or domain scope. There are existing use cases where support of other flooding scopes is desirable. This document defines new Protocol Data Units (PDUs) that provide support for new flooding scopes as well as additional space for advertising information targeted for the currently supported flooding scopes. This document also defines extended Type-Length-Values (TLVs) and sub-TLVs that are encoded using 16-bit fields for Type and Length.

The protocol extensions defined in this document are not backwards compatible with existing implementations and so must be deployed with care.')

[Ballot comment]
Quoting Melinda, part of her OPS-DIR review:
  This document introduces new IS-IS flooding scope PDUs, and defines
  new TLVs and sub-TLVs with 16-bit type and length fields.  I feel this
  document is ready for publication, with a note that RFC 4444 (the IS-IS
  MIB) should probably be updated at some point in the future.

I don't believe an extra note is needed in the draft, in light of http://www.ietf.org/iesg/statement/writable-mib-module.html
The only one I could think of is: "The old RFC4444 MIB module doesn't support this new functionality", which is so obvious than it doesn't add any value.

[Ballot comment]
Thanks for Discussing with me. I like your proposed text, which is

"When deploying support for a new flooding scope correct operation therefore
requires both FS PDUs and the new scope be supported by all routers in the flooding domain of the new scope."

[Ballot comment]
Note that my Discuss question is different from my usual "could you give an example of why use of that scope could usefully be enabled before all routers in the flooding domain for a given scope support that scope?" whining.

I'm curious about that, too, but don't think my usual question qualifies as a Discuss.

[Ballot discuss]
In this text:

5.  Deployment Considerations

  Introduction of new PDU types is incompatible with legacy
  implementations.  Legacy implementations do not support the FS
  specific Update process(es) and therefore flooding of the FS-LSPs
  throughout the defined scope is unreliable when not all routers in
  the defined scope support FS PDUs.  Further, legacy implementations
  will likely treat the reception of an FS PDUs as an error.  Even when
  all routers in a given scope support FS PDUs, if not all routers in
  the flooding domain for a given scope support that scope, then
  flooding of the FS-LSPs may be compromised.  Therefore all routers in
  the flooding domain for a given scope SHOULD support both FS PDUs and
                                        ^^^^^^
  the specified scope before use of that scope can be enabled.

Is it obvious to those more skilled in the art than most TSV ADs why SHOULD is appropriate here, instead of MUST? "flooding is unreliable" and "flooding may be compromised" sound pretty dire.

[Ballot comment]
Note that my Discuss question is different from my usual "could you give an example of why use of that scope can be enabled before all routers in the flooding domain for a given scope support that scope?" whining.

I'm curious about that, too, but don't think my usual question qualifies as a Discuss.

[Ballot comment]
Thanks for including the explicit and clear statement on backwards
compatibility.

---

A note for the responsible AD: This document creates a registry that
needs a designated expert. I suggest you add an item to the Management
Items part of the agenda to assign the experts.

IESG/Authors/WG Chairs:

IANA has reviewed draft-ietf-isis-fs-lsp-01.  Authors should review the comments and/or questions below.  Please report any inaccuracies and respond to any questions as soon as possible.

IANA's reviewer has the following comments/questions:

QUESTION: should the new registry be created at http://www.iana.org/assignments/isis-pdu, or at some other existing URL, or at a new URL? See http://www.iana.org/protocols for the current registries.

IANA understands that upon approval of this document, there are three actions that need to be completed.

First, in the IS-IS PDU Registry at

http://www.iana.org/assignments/isis-pdu/

three new PDUs are to be registered as follows:

Value: [ TBD-at-registration ]
Description: FS-LSP
Reference: [ RFC-to-be ]

Value: [ TBD-at-registration ]
Description: FS-CSNP
Reference: [ RFC-to-be ]

Value: [ TBD-at-registration ]
Description: FS-PSNP
Reference: [ RFC-to-be ]

IANA notes that the authors have suggested values of 10, 11 and 12 for these assignments.

Second, a new registry is to be created called the "LSP Flooding Scoped Identifier Registry." Values in this registry will range from 1 to 127 inclusive. Values 1 - 63 are reserved for PDUs which use standard TLVs and standard sub-TLVs. Values 64 - 127 are reserved for PDUs which use extended TLVs and extended sub-TLVs.

IANA Question (as above) -> Is this new registry intended to be part of an existing category and URL, or should IANA create a new, standalone page?

Maintenance of this registry will be done via Expert Review as defined in RFC 5226.

There are initial values in this new registry as follows:

Value Description FS LSP ID Format TLV Format Reference
----- -------------------------- ---------------- ---------- -------------
1 Level 1 Circuit Flooding Scope Extended Standard [ RFC-to-be ]
2 Level 2 Circuit Flooding Scope Extended Standard [ RFC-to-be ]
3 Level 1 Flooding Scope Extended Standard [ RFC-to-be ]
4 Level 2 Flooding Scope Extended Standard [ RFC-to-be ]
5 Domain-wide Flooding Scope Extended Standard [ RFC-to-be ]
6-63 Unassigned
64 Level 1 Circuit Flooding Scope Extended Extended [ RFC-to-be ]
65 Level 2 Circuit Flooding Scope Extended Extended [ RFC-to-be ]
66 Level 1 Flooding Scope Extended Extended [ RFC-to-be ]
67 Level 2 Flooding Scope Extended Extended [ RFC-to-be ]
68 Domain-wide Flooding Scope Extended Extended [ RFC-to-be ]
69-127 Unassigned

Third, in the IS-IS TLV Codepoints registry at

http://www.iana.org/assignments/isis-tlv-codepoints/

If the IESG-designated experts approve, IANA will register the following new TLV:

Type: [ TBD-at-registration ]
Description: Circuit Scoped Flooding Support
IIH: Y
LSP: N
SNP: N
Purge: N
Status/Reference: [ RFC-to-be ]

NOTE: IANA is asking the IESG-designated experts to review this request. As the IS-IS TLV Codepoints registry is maintained via Expert Review as defined in RFC 5226, IANA cannot make this assignment without expert approval.

IANA notes that the authors suggest the value of 243 for this codepoint.

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 only to confirm what actions will be performed.

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (IS-IS Flooding Scope LSPs) to Proposed Standard


The IESG has received a request from the IS-IS for IP Internets WG (isis)
to consider the following document:
- 'IS-IS Flooding Scope LSPs'
  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 2014-06-03. 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


  Intermediate System To Intermediate System (IS-IS) provides efficient
  and reliable flooding of information to its peers.  However the
  current flooding scopes are limited to either area wide scope or
  domain wide scope.  There are existing use cases where support of
  other flooding scopes are desirable.  This document defines new
  Protocol Data Units (PDUs) which provide support for new flooding
  scopes as well as additional space for advertising information
  targeted for the currently supported flooding scopes.  This document
  also defines extended TLVs and sub-TLVs which are encoded using 16
  bit fields for type and length.

  The protocol extensions defined in this document are not backwards
  compatible with existing implementations and so must be deployed with
  care.





The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-isis-fs-lsp/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-isis-fs-lsp/ballot/


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

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 24 February 2012.

(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.

(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

  Relevant content can frequently be found in the abstract
  and/or introduction of the document. If not, this may be
  an indication that there are deficiencies in the abstract
  or introduction.

        This document adds new flooding scopes to IS-IS using new PDUs (protocol
        data units). Additionally extra advertising space is added for existing
        and new flooding scopes as well as extending TLV type and length to
        allow 16 bit values. These extensions are not backward compatible.


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?

        There was no controversy in the WG over this draft.

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, 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?

        Currently one experimental version is known to exist, and one vendor
        known so far with plans to implement.

Personnel

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

        Shepherd: Christian Hopps.
        AD: Alia Atlas.

(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 reviewed this document and believe it 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

(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.

        No special review is needed.

(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 specific 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.

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

        No IPR has been 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? 

        Strong consensus among a few WG experts.

(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 http://www.ietf.org/tools/idnits/ and the Internet-Drafts
Checklist). Boilerplate checks are not enough; this check needs to be
thorough.

        None.

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

        N/A.

(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?

        None.

(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.

        No.

(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).

        IANA section has been reviewed and is sufficient. Entries to existing
        registries (PDU) and IS-IS code-points, as well as a new registry for
        flooding scopes, and finally extension of the type space in IS-IS
        code-points registry are clearly articulated.

(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.

        A new registry for definition of flooding scopes is being
        created. Existing IS-IS expert review is considered sufficient.

(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.

        N/A.