Multipoint Label Distribution Protocol In-Band Signaling in a Virtual Routing and Forwarding (VRF) Table Context
draft-ietf-l3vpn-mldp-vrf-in-band-signaling-03

[Ballot comment]
Thanks for the discussion on the handling of scoped IPV6 scoped multicast addresses.

Moved to a COMMENT for historical reasons...

I have a general concern, but I am not sure if it is the fault of this document, RFC 6513, or RFC 6826 so let's discuss it here for the time being...

How are non-global-scoped IPv6 multicast addresses handled?  There is no discussion in this document about verifying that the creation of an MDT is not violating a scope boundary.  RFC 4007 (section 10) is very clear on the rules that must be followed when creating forwarding state.  If these rules are not followed, scoped packets can leak out of their allowed zone creating a vulnerability.  Notionally, I would have expected to see something in Section 2 saying that scopes need to be checked as a part of the signaling procedure.

There does not appear to be any discussion of scoped addresses in 6513, 6512, or 6826.  Where in the MPLS VPN specs is support for scoped multicast addresses defined?

[Ballot discuss]
I have a general concern, but I am not sure if it is the fault of this document, RFC 6513, or RFC 6826 so let's discuss it here for the time being...

How are non-global-scoped IPv6 multicast addresses handled?  There is no discussion in this document about verifying that the creation of an MDT is not violating a scope boundary.  RFC 4007 (section 10) is very clear on the rules that must be followed when creating forwarding state.  If these rules are not followed, scoped packets can leak out of their allowed zone creating a vulnerability.  Notionally, I would have expected to see something in Section 2 saying that scopes need to be checked as a part of the signaling procedure.

There does not appear to be any discussion of scoped addresses in 6513, 6512, or 6826.  Where in the MPLS VPN specs is support for scoped multicast addresses defined?

[Ballot comment]

It seems kind of incredible that the security
considerations here are so simple, when we're glueing
together two different ways to do multicast.  Surely at
least the security considerations relevant to PIM ought be
noted?

Would it (un)fair of me to guess that perhaps nobody has
really looked for potential new vulnerabilities here?

As it happens, I don't have the time before the telechat,
nor probably the MC clue, to help with that so this is not
a DISCUSS, but you could set my mind at rest if you told
me that yes, a bunch of folks with that clue and some
security clue have really spent time looking at this.

[Ballot comment]
The last paragraph of Section 1 begins:

  In order to use the mLDP in-band signaling procedures...

...but "the mLDP in-band signaling" is a new term. It turns out that it
meas exactly what the previous paragraph ended up saying, viz.

  encoded into the mLDP FEC element.

So I suggest that you update the end of the previous paragraph to read

  encoded into the mLDP FEC element in what this document terms "mLDP
  in-band signaling."

IESG/Authors/WG Chairs:

IANA has reviewed draft-ietf-l3vpn-mldp-vrf-in-band-signaling-03.  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:

IANA understands that, upon approval of this document, there is a single action which must be completed.

In the the Label Distribution Protocol (LDP) Parameters registry "LDP MP Opaque Value Element basic type," located at

http://www.iana.org/assignments/ldp-namespaces/

four new LDP MP Opaque Value Elements are to be registered as follows:

Value [ TBD-at-registration ]
Name: Transit VPNv4 Source TLV type
Reference: [ RFC-to-be ]

Value [ TBD-at-registration ]
Name: Transit VPNv6 Source TLV type
Reference: [ RFC-to-be ]

Value [ TBD-at-registration ]
Name: Transit VPNv4 Bidir TLV type
Reference: [ RFC-to-be ]

Value [ TBD-at-registration ]
Name: Transit VPNv6 Bidir TLV type
Reference: [ RFC-to-be ]

IANA notes that the authors have requested a value of:

250 for the Transit VPNv4 Source TLV type, and
251 for the Transit VPNv6 Source TLV type

IANA will make every effort to accommodate those requests.

IANA understands that this is the only action 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 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:  (Multipoint Label Distribution Protocol In-Band Signaling in a VRF Context) to Proposed Standard


The IESG has received a request from the Layer 3 Virtual Private Networks
WG (l3vpn) to consider the following document:
- 'Multipoint Label Distribution Protocol In-Band Signaling in a VRF
  Context'
  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 2014-02-12. 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


  An IP Multicast Distribution Tree (MDT) may traverse both label
  switching (i.e. - Multi-Protocol Label Switching, or MPLS) and non-
  label switching regions of a network.  Typically the MDT begins and
  ends in non-MPLS regions, but travels through an MPLS region.  In
  such cases, it can be useful to begin building the MDT as a pure IP
  MDT, then convert it to an MPLS Multipoint Label Switched Path (MP-
  LSP) when it enters an MPLS-enabled region, and then convert it back
  to a pure IP MDT when it enters a non-MPLS-enabled region.  Other
  documents specify the procedures for building such a hybrid MDT,
  using Protocol Independent Multicast (PIM) in the non-MPLS region of
  the network, and using Multipoint Extensions to Label Distribution
  Protocol (mLDP) in the MPLS region.  This document extends those
  procedures to handle the case where the link connecting the two
  regions is a "Virtual Routing and Forwarding Table" (VRF) link, as
  defined in the "BGP IP/MPLS VPN" specifications.  However, this
  document is primarily aimed at particular use cases where VRFs are
  used to support multicast applications other than Multicast VPN.




The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-l3vpn-mldp-vrf-in-band-signaling/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-l3vpn-mldp-vrf-in-band-signaling/ballot/


The following IPR Declarations may be related to this I-D:

  http://datatracker.ietf.org/ipr/2216/

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?

  The requested status is Proposed Standard. The Document is a protocol
  specification which requires the assignment of code points by the IANA, from a
  "Standards Action" registry. This justifies the type of RFC being requested.

(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

  An IP Multicast Distribution Tree (MDT) may traverse both label
  switching (i.e. - Multi-Protocol Label Switching, or MPLS) and non-
  label switching regions of a network.  Typically the MDT begins and
  ends in non-MPLS regions, but travels through an MPLS region.  In
  such cases, it can be useful to begin building the MDT as a pure IP
  MDT, then convert it to an MPLS Multipoint Label Switched Path (MP-
  LSP) when it enters an MPLS-enabled region, and then convert it back
  to a pure IP MDT when it enters a non-MPLS-enabled region.  Other
  documents specify the procedures for building such a hybrid MDT,
  using Protocol Independent Multicast (PIM) in the non-MPLS region of
  the network, and using Multipoint Extensions to Label Distribution
  Protocol (mLDP) in the MPLS region.  This document extends those
  procedures to handle the case where the link connecting the two
  regions is a "Virtual Routing and Forwarding Table" (VRF) link, as
  defined in the "BGP IP/MPLS VPN" specifications.  However, this
  document is primarily aimed at particular use cases where VRFs are
  used to support multicast applications other than Multicast VPN.

Working Group Summary

  The WG supports this Document and its progress.

Document Quality

  Two implementations of this protocol specification are known.
  The Document has been reviewed by experts and these experts are acknowledged
  in the appropriate section of the Document.

Personnel

  Martin Vigoureux (L3VPN co-chair) is the Document Shepherd
  Stewart Bryant is the Responsible Area Director

(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 Document Shepherd has reviewed the recent revisions of this document and
  the last version as well. The 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 concern. The Document has been thoroughly reviewed as part of a Routing
  Directorate review.

(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 specific additional 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.

  There is no specific issue or concern with this Document.

(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 have confirmed that they are not aware of any undisclosed IPR
  that applies to this Document.

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

  Yes, an IPR disclosure exists: https://datatracker.ietf.org/ipr/2216/
  The formal disclosure came a little bit late in the process (at the time of WG Last
  Call). However, the lead author had notified the Working Group (at the time of
  adoption by the Working Group) that an existing IPR disclosure (on another draft)
  was also applicable to this Document. This information has been reminded to the
  group within the WG Last Call e-mail. Satisfactory explanations were also given
  regarding why the appropriate disclosure took time. The Working Group was given
  the opportunity to speak with regards to the "late" disclosure. No concern has
  been raised.

(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?

  The consensus is solid. 

(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 such extreme position/situation exists for that Document.

(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.

  The result of the thorough nits check is clean.

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

  No formal review criteria needed.

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

  Yes. The references are appropriately categorized.

(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?

  No. All Normative references are in RFC status.

(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 downward reference.

(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.

  This Document does not change the status of existing RFCs. However as per the
  Document, it "extends the procedures from RFC6826 to handle the case where the
  link connecting the two regions is a "Virtual Routing and Forwarding Table" (VRF)
  link, as defined in the "BGP IP/MPLS VPN" specifications [RFC6513].", but no
  changes are brought to RFC6826.

(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 requests the IANA to assign 4 new code-points from an existing
  registry (LDP MP Opaque Value Element basic type), defined by RFC 6388 and for
  which the registration procedure is by Standards Action.
  Out of these 4 new code points the Documents kindly asks the IANA to assign two
  specific values (250 for the Transit VPNv4 Source TLV and 251 for the Transit
  VPNv6 Source TLV). These values are strongly suggested as they are already part
  of an existing implementation. An early allocation procedure should have been
  followed in such a situation. It has not been the case. The WG co-Chairs have
  decided that initiating the procedure when the document is ready for publication
  would not bring a lot of benefits, thus the maintained direct request in the
  Document.

(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.

  no new registry is required and thus no expert review needed.

(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.

  no such section in the Document.