Inter-Area Point-to-Multipoint (P2MP) Segmented Label Switched Paths (LSPs)
draft-ietf-mpls-seamless-mcast-17

[Ballot comment]

Apologies, I didn't really have time to read and
understand this, but I got triggered by the mention of
"thousands of PEs" in the intro and wonder if we think the
existing security mechanisms referred to in the security
considerations would scale appropriately for such cases.
Am I worrying over nothing or is there maybe a bit more
work (or text) needed to secure such a setup?

[Ballot comment]
For the Global Administrator field, it would be really nice to specify that the IP address needs to be routeable and within what scope (area, AS, inter-AS).  I think the answer is just AS.  This comes up because a recommendation is to use a router's loopback address - and frequently those are deliberately not routeable outside the AS.

[Ballot discuss]
This time I'm going to be the one to file a DISCUSS over reference categorization. 

Why are these references Informative?  It seems like they're pretty much all critical for implementing the requirements stated in this document.

[Ballot comment]
Some minor editorial quibbles:

OLD: "unique [RFC2826] root zone[ROOTZONE]."

NEW: "unique root zone [RFC2826][ROOTZONE]."

RFC 4035 uses "authoritative name server", not "service".

IESG/Authors/WG Chairs:

IANA has reviewed draft-ietf-mpls-seamless-mcast-15.  Authors should review the comments and/or questions below.  Please report any inaccuracies and respond to any questions as soon as possible.

We received the following comments/questions from the IANA's reviewer:

IANA understands that, upon approval of this document, there are three actions which IANA must complete.

First, in the Transitive IPv4-Address-Specific Extended Community Sub-Types subregistry of the the Border Gateway Protocol (BGP) Extended Communities registry, IANA has assigned the value 0x12 in the Transitive IPv4-Address-Specific Extended Community Sub-Types registry for Inter-area P2MP Segmented Next-Hop. IANA will change the reference from the Internet Draft to [ RFC-to-be ].

Second, in the Transitive IPv6-Address-Specific Extended Community Types subregistry of the Border Gateway Protocol (BGP) Extended Communities registry located at:

http://www.iana.org/assignments/bgp-extended-communities/

IANA has assigned the value 0x0012 for Inter-area P2MP Segmented Next-Hop. IANA will change the reference from the Internet Draft to [ RFC-to-be ].

Third, in the P-Multicast Service Interface Tunnel (PMSI Tunnel) Tunnel Types subregistry of the Border Gateway Protocol (BGP) Parameters registry located at:

http://www.iana.org/assignments/bgp-parameters/

a new tunnel type will be registered as follows:

Value: [ TBD-at-registration ]
Meaning: Transport Tunnel
Reference: [ RFC-to-be ]

The value 0x08 is requested.

IANA understands that these three actions are the only ones 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. 

Please note that IANA cannot reserve specific values. However, early allocation is available for some types of registrations. For more information, please see RFC 7120.

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Inter-Area P2MP Segmented LSPs) to Proposed Standard


The IESG has received a request from the Multiprotocol Label Switching WG
(mpls) to consider the following document:
- 'Inter-Area P2MP Segmented 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 2015-02-02. 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 describes procedures for building inter-area point-to-
  multipoint (P2MP) segmented service LSPs by partitioning such LSPs
  into intra-area segments and using BGP as the inter-area routing and
  label distribution protocol. Within each IGP area the intra-area
  segments are either carried over intra-area P2MP LSPs, using P2MP LSP
  hierarchy, or instantiated using ingress replication.  The intra-area
  P2MP LSPs may be signaled using P2MP RSVP-TE or P2MP mLDP. If ingress
  replication is used within an IGP area, then (multipoint-to-point)
  LDP LSPs or (point-to-point) RSVP-TE LSPs may be used in the IGP
  area. The applications/services that use such inter-area service LSPs
  may be BGP Multicast VPN, VPLS multicast, or global table multicast
  over MPLS.

The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-mpls-seamless-mcast/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-mpls-seamless-mcast/ballot/


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

  http://datatracker.ietf.org/ipr/2047/

AD review
=====

Hello authors,

I have conducted my usual AD review of this document to attempt to
catch issues that would otherwise show in IETF last call or IESG
evaluation.

There are number of small nits listed below. None of these needs
delay the document and you should feel free to debate the points with
me rather than blindly accepting my view.

I will start the IETF last call and enter these as last call comments.
You can then address them together with any other review comments you
receive during last call.

Thanks for the work.

Adrian

===

idnits reveals that the copyright year needs to be 2015. Please update
that if you revise the document.

idnits also points out that you probably don't need the boilerplate for
pre-RFC5378 work. unless you are sure you need it, please take it out.

---

I think that the RFC Editor will need your help expanding some of the
abbreviations that are not listed as "well known" in the list at
http://www.rfc-editor.org/rfc-style-guide/abbrev.expansion.txt
You might kick this off by doing a scrub yourselves.

---

Section 3 line 1
s/suppose/assumed/

---

5.1.2 and 5.2.2 titles

s/re-advertise/re-advertised/                                     

---

5.1.3 has

  To avoid requiring ABRs to participate in the propagation of C-
  multicast routes, this document requires ABRs NOT to modify BGP Next
  Hop when re-advertising Inter-AS I-PMSI A-D routes.

"NOT" is not a 2119 term in its own right.
Suggest you rephrase as

  To avoid requiring ABRs to participate in the propagation of C-
  multicast routes, this document specifies that ABRs MUST NOT 
  modify BGP Next Hop when re-advertising Inter-AS I-PMSI A-D routes.

---

In 6.1.2

  If the application is global table multicast, then the unicast routes
  to multicast sources/RPs SHOULD carry the "VRF Route Import" Extended
  Community [RFC6514] where the IP address in the Global Administrator
  field is set to the IP address of the PE or ASBR advertising the
  unicast route.

I wondered about this "SHOULD". Trying to decide why we might decide to
vary that and what the consequences would be.

Similarly one para later...

  Further, if the application is global table multicast, then the BGP
  unicast routes that advertise the routes to the IP addresses of
  PEs/ASBRs/ABRs SHOULD carry the Inter-area P2MP Segmented Next-Hop
  Extended Community.

---

7.2.2.1

  This section applies only if it is desirable to send a particular (S,
  G) or (*, G) global table multicast flow only to those egress PEs
  that have receivers for that multicast flow.

Is this s/desirable/desired/ ?
If not then some guidance as to how to judge when it is desirable.
If so, then perhaps you could be a little less passive-voice: who
desires it?

---

7.2.2.2

  It may be desirable for an ingress PE to carry multiple multicast
  flows associated with the global table multicast over the same inter-
  area P2MP service LSP.

Can you give guidance as to why it might be desirable?
Or possible (as above) s/desirable for/desired that/ also adding some
explanation about who has the desire (and possible why).

---

7.2.3

  To allow the egress PE
  to determine the sender upstream node, the intra-area P2MP LSP must
  be signaled with no PHP, when the mapping between the inter-area P2MP
  service LSP for global table multicast service and the intra-area
  P2MP LSP is many-to-one.

The lower case "must" jumped out. Probably upper case?

---

Section 14

Is the term "transport LSP" introduced by this document?
If so, a little more definition would be nice (just a few words to make
it clear that you are defining the term).
If not, can you supply a reference.

---

After 38 pages of spec you have just five lines of security
considerations. You don't even mention BGP security directly.

I confess that I don't see anything obvious that is missing, but are
there no specific risks associated with this approach? No amplification
through mcast?

The MPLS working group requests that

                    Inter-Area P2MP Segmented LSPs

                draft-ietf-mpls-seamless-mcast-14.txt

is published as an RFC on the Standards Track.

(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?

  We want to start this document up on the Standards Track as a Proposes
  Standard.
  The document header says Standards Track.

  Proposed Standard is the right type of RFC, since the document specifies
  protocol, procedures and information elements.

(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 describes procedures for building inter-area P2MP
  segmented service LSPs by partitioning such LSPs
  into intra-area segments and using BGP as the inter-area routing and
  label distribution protocol.

  Within each IGP area the intra-area segments are either carried over
  intra-area P2MP LSPs, using P2MP LSP hierarchy, or instantiated using
  ingress replication. 

  The intra-area P2MP LSPs may be signaled using P2MP RSVP-TE (RFC 4875)
  or mLDP (RFC 63 88). If ingress replication is used within an IGP area, then
  LDP or RSVP-TE LSPs may be used.

  BGP VPN Multicast, VPLS multicast, or global table multicast over MPLS are
  applications/services that may use such inter-LSPs.

Working Group Summary

  The WG process has been straightforward, there is a general agreement in the
  working group that support for multicast service is needed and that there are
  synergies if we can use the the same method for multiple cases
 
  There have been no controversies around this draft and the support for this
  document is good.

Document Quality

  We are currently aware of one implementation.
  An implementation poll has been sent to the working group and the Shepherd
  Write-up will be updated as soon as we have more information.

  There has been no other reviews than the MPLS-RT and WGLC, MIB Doctor,
  Media Type or other expert reviews are not necessary for this document.


Personnel

  Loa Andersson is the Document Shepherd.
  Adrian Farrel 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.

  This document has been part of the discussion around Seamless MPLS,
  the Shepherd has reviewed at least three times
  - when the (individual) document first appeared (this document were part of
    a larger discussion on "Seamless MPLS" and attracted quite an interest
    from the start
  - while preparing the preparing mpls-rt review and working group adoption
    poll
  - prior to and after working group last call.


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

  No such 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.

  No such reviews 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 such 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 has state on the MPLS wg mailing list that they are
  unaware of any other IPRs than what has been disclosed to the IETF.

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

  There is one IPR disclosed against this document, it was brought to the
  working group attention at working group last call. The IPR disclosure did
  not generate any discussion during the wglc, the shepherd has interpreted
  this as that the conditions related to the IPR is acceptable for the working
  group.

  Note: This ID were going through the wg adoption poll in April 2011, prior to
  when we routinely started to do IPR polls prior to the wg adoption poll.
  The IPR was disclosed in April 2013.

(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 working group support this document.

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

  No real nits, the date in the document is given as "June 30 2014" while the
  nits toll expects "June 30, 2014" this generates 3 miscellaneous warnings.

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

  No such formal reviews required.

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

  Yes, the references are correctly split into normative and informative.into
  references.

(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?

  All normative references are to existing RFCs, with one exception. One
  normative references is to draft-ietf-l3vpn-pmsi-registry, that draft is in
  AUTH48 and is like to become an RFC prior to the IESG review of this
  document.

(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 refernces.

(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.

  The status of no other document will be change when this document is
  publsihed.


(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 shepherd has reviewed the IANA section and code point allocations
  several times. The IANA section is clear and well written.

  However in the earlier version of the document the IANA section included
  addition of code points to a table specified in RFC 6514, but for which an
  IANA registry never was created.

  The Shepherd in the early reviews assumed that since the allocation were
  mentioned in the IANA section it was requesting an IANA action. Having
  understood the situation and after consulting with the responsible AD it was
  decided to hold this document and write the document that creates this
  registry. The new document (draft-ietf-l3vpn-pmsi-registry) is now in AUTH48
  and this document correctly request a code point to be allocated form the
  new registry. 

(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 such 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, etc.

  No such reviews needed.