Ingress Replication Tunnels in Multicast VPN
draft-ietf-bess-ir-05

[Ballot comment]
I think the document is hard to read, for a number of reasons (the complexity of the underlying tech, plenty of options in it, incremental patch style to specification, and so on). I don't think any of the underlying reasons left much choice for the WG to produce something more easily analysable and understandable. However, while it has been difficult for me and Gen-ART reviewers to review it, I've been convinced that there's been enough other people who have reviewed it. I *am* however nervous that we're missing some cases or corner cases, but the world is certainly a better place with this document published than not.

Thanks for your hard work on this.

[Ballot comment]
Considering the discussion among the IESG, I wanted to give a strong
endorsement for this document. Yes, the document is "complex" to
read as it updates RFC6513/6514, and both of these documents required
the reader to have normatively understood many other RFCs. Yes, the
subject is complex for a non-subject expert reader. This document
provides the "additional details" to implement complex capabilities
(e.g. multi-vendor interoperability make before break procedures) these
vendors (and the WG as noted by the Acknowledgements and list
discussion) have found lacked in clarity in the original RFCs. I thank
the authors and WG for taking the time to write this RFC as this
additional work on implementation aspects after an RFC is
rubber-stamped is critical.

On many of the questions raised, a good discussion can be found
on the list, especially Thomas's and Eric's thread:
https://mailarchive.ietf.org/arch/msg/bess/AydZrp0Lf9fUohKrgVHG9kzbycY

[Ballot comment]
Considering the discussion among the IESG, I wanted to give a strong endorsement for this document.
Yes, the document is "complex" to read as it updates RFC6513/6514, and both of these documents required
the reader to have normatively understood many other RFCs. Yes, the subject is complex for a non-subject
expert reader. This document provides the "additional details" to implement complex capabilities
(e.g. multi-vendor interoperability make before break procedures) these vendors (and the
WG as noted by the Acknowledgements and list discussion) have found lacked in clarity in the original
RFCs. I thank the authors and WG for taking the time to write this RFC as this additional work on
implementation aspects after an RFC is rubber-stamped is critical.

On many of the questions raised, a good discussion can be found on the list, especially Thomas's
and Eric's thread:
https://mailarchive.ietf.org/arch/msg/bess/AydZrp0Lf9fUohKrgVHG9kzbycY

[Ballot comment]
I have some concerns about this document that I don't believe can be easily fixed.

This  document is extremely hard to read and understand, and therefore comprehend if there are any implications to the information provided. I'm really not sure that this can be addressed here without a significant rewrite.  (that might be because the topic itself is deep)

A second is related to how the document positions itself. Its status is for Standards Track, yet in the introduction it says:

In this document, we provide a clearer and more explicit conceptual
  model for IR P-tunnels, clarifying the relationship between an IR
  P-tunnel and the unicast tunnels that are used for data transmission
  along the IR P-tunnel.

and

This document does not provide any new protocol elements, or any
  fundamentally new procedures; its purpose is to make explicit just
  how a router is to use the protocol elements and procedures of
  [RFC6513] and [RFC6514] to identify an IR P-tunnel, to join an IR
  P-tunnel, and to prune itself from an IR P-tunnel.

Which to me screamed out informational,  while then updating 6513 and 6514. However there are parts of the document that imply a semantic change in the use of fields or labels. Eg sect 10, use of timers when switching Upstream Multicast Hop.. so strongly suggesting a standards position.

It feels like this document started out to do one thing, eg clarify the model of IR P-Tunnels and then acquired an extended set of tasks in dealing with MPLS label allocation policies.

As I can't see a way to make a clear assessment of this document, I am taking an ABSTAIN position, and I will not block publication.

[Ballot discuss]
I would like to Discuss with the other ADs tomorrow on how they perceived the content in the draft, and how well they've been able to review it and convince themselves of its correctness. I had trouble and my Gen-ART reviewer had trouble....

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

IANA has reviewed draft-ietf-bess-ir-03.txt, which is currently in Last Call, and has the following comments:

We understand that this document doesn't require any IANA actions.

While it's often helpful for a document's IANA Considerations section to remain in place upon publication even if there are no actions, if the authors strongly prefer to remove it, IANA does not object.

If this assessment is not accurate, please respond as soon as possible.

Thank you,

Sabrina Tanamal
IANA Specialist
ICANN

The following Last Call announcement was sent out:

From: The IESG
To: "IETF-Announce"
CC: aretana@cisco.com, thomas.morin@orange.com, bess-chairs@ietf.org, draft-ietf-bess-ir@ietf.org, bess@ietf.org
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Ingress Replication Tunnels in Multicast VPN) to Proposed Standard


The IESG has received a request from the BGP Enabled ServiceS WG (bess)
to consider the following document:
- 'Ingress Replication Tunnels in Multicast VPN'
  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 2016-08-10. 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


  RFCs 6513, 6514, and other RFCs describe procedures by which a
  Service Provider may offer Multicast VPN service to its customers.
  These procedures create point-to-multipoint (P2MP) or multipoint-to-
  multipoint trees across the Service Provider's backbone.  One type of
  P2MP tree that may be used is known as an "Ingress Replication (IR)
  tunnel".  In an IR tunnel, a parent node need not be "directly
  connected" to its child nodes.  When a parent node has to send a
  multicast data packet to its child nodes, it does not use layer 2
  multicast, IP multicast, or MPLS multicast to do so.  Rather, it
  makes n individual copies, and then unicasts each copy, through an IP
  or MPLS unicast tunnel, to exactly one child node.  While the prior
  MVPN specifications allow the use of IR tunnels, those specifications
  are not always very clear or explicit about how the MVPN protocol
  elements and procedures are applied to IR tunnels.  This document
  updates RFCs 6513 and 6514 by adding additional details that are
  specific to the use of IR tunnels.




The file can be obtained via
https://datatracker.ietf.org/doc/draft-ietf-bess-ir/

IESG discussion can be tracked via
https://datatracker.ietf.org/doc/draft-ietf-bess-ir/ballot/


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

=== AD Review of draft-ietf-bess-ir-03 ===

I just finished reading this document.  Besides a couple of minor comments (see below), it concerns me that it is not straight forward to tell how/where this document updates to 6513/6514.  Is the intent for the content of this document to replace all the IR-specific text in 6513/6514, or are there parts of 6513/6514 that are unaffected and the text in the document represents just clarifications/additions (the Abstract does say that it "updates RFCs 6513 and 6514 by adding additional details that are specific to the use of IR tunnels.").  However, without specific references to where the clarifications/additions apply, I'm just left chasing text back and forth in an exercise that could easily be solved by the authors.

For example, Section 6. (A Note on IR P-tunnels and 'Discarding Packets from the Wrong PE') talks about the need to determine a packet's ingress PE (in order to apply the procedures of Section 9.1.1 of RFC6513), and it concludes by saying that if the ingress PE can't be determined then the procedures in 9.1.2 or 9.1.3 of RFC6513 are required.  That is pretty much the same thing as this text in Section 6.4.5. (Ingress Replication) of RFC6513: "Deployment of ingress replication with such P-tunnel technology MUST NOT be done unless it is known that the deployment relies entirely on the procedures of Sections 9.1.2 or 9.1.3 for duplicate prevention." (where "such" refers to not being able to identify the ingress PE).  The fact that there is no contradiction (at least here) is a good thing.  In my opinion, a pointer to Section 6.4.5 in RFC6513 would help the reader in understanding the context of the details in this document…and save their time having to find the relevant sections in other documents.


Thanks!

Alvaro.


Minor Comments:
p1. Replace the MVPN-XNET with RFC7900.
p2. s/leaf info required/leaf information required (per rfc6514).
p3.  It would be very nice if the Introduction contained references to a section after each "in this document…".

(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?

Standard Track

(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

  RFCs 6513, 6514, and other RFCs describe procedures by which a
  Service Provider may offer Multicast VPN service to its customers.
  These procedures create point-to-multipoint (P2MP) or multipoint-to-
  multipoint trees across the Service Provider's backbone.  One type of
  P2MP tree that may be used is known as an "Ingress Replication (IR)
  tunnel".  MVPN specifications allow the use of IR tunnels, those specifications
  are not always very clear or explicit about how the MVPN protocol
  elements and procedures are applied to IR tunnels.  This document
  updates RFCs 6513 and 6514 by adding additional details that are
  specific to the use of IR tunnels.

Working Group Summary
 
  There was consensus in the WG that a clarification document was
  needed to completement RFC6513/RFC6514.

Document Quality

  The document is of very good technical and editorial quality, and
  matches its goal of bringing clarifications to existing specs.

Personnel

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

The sheperd is Thomas Morin, and
the responsible AD is Alvaro Retana.

(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 did a review of the document both during WGLC
(leading to a few changes), and a final review.

(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.

(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 particular concern.

(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.

(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? 

Good consensus among the contributors on multicast VPN.

(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.

No.

(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.

Only one nit to address: RFC2119 needs to be added.

(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?

No.

(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).

No IANA action required, this is consistant with the document content.

(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.

N/A

(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