Provider Backbone Bridging Combined with Ethernet VPN (PBB-EVPN)
draft-ietf-l2vpn-pbb-evpn-10

[Ballot comment]
Question.

Section 8 discusses ARP snooping. Is there a need to discuss IGMP and MLD snooping as well (e.g., by referring to RFC 4541).

Note that MLD snooping might affect how packets are forwarded for neighbour discovery in IPv6.

[Ballot comment]
Would expanding "PBB-EVPN" in the title be helpful to anyone except me? :-)

In section 3, I read

  Single-Active Redundancy Mode: When only a single PE, among a group
  of PEs attached to an Ethernet segment, is allowed to forward traffic
  to/from that Ethernet Segment, then the Ethernet segment is defined
  to be operating in Single-Active redundancy mode.

  All-Active Redundancy Mode: When all PEs attached to an Ethernet
  segment are allowed to forward traffic to/from that Ethernet Segment,
  then the Ethernet segment is defined to be operating in All-Active
  redundancy mode.
 
and wondered if it would ever be the case that some, but not all, PEs were allowed to forward traffic.

I noticed a "the the".

[Ballot comment]
Thanks to Adrian for connecting in the SecDir review.  I responded to the thread he restarted as a result of it being included in Adrian's comments already.  This may be a repeat to that thread for some.

My take on the review is that Catherine was asking if the advantages added by this draft also result in some security improvements over the referenced security considerations section.  The referenced section mentions a problem with duplicate MAC addresses and this draft in section 10.1, 10.2, and 10.3 discuss the aggregation of MACs - does this also lead to a security advantage in that the prior concern is mitigated? 

Then does the advantage in 10.5 that provides more granular forwarding policy support also have a security advantage?

If so, it would be good to state this, if not, a simple sentence that says no additional security considerations are added in this draft would be helpful.

Here is a link to Catherine's review:
https://www.ietf.org/mail-archive/web/secdir/current/msg05400.html

[Ballot comment]
from Melinda Shore's ops-dir review:



I have reviewed this document as part of the Operational directorate's
ongoing effort to review all IETF documents being processed by the
IESG. These comments were written with the intent of improving the
operational aspects of the IETF drafts. Comments that are not addressed
in last call may be included in AD reviews during the IESG review.
Document editors and WG chairs should treat these comments just like
any other last call comments.

Summary: this document is ready

This draft describes a mechanism for reducing the number of BGP MAC
advertisement routes, provide MAC address mobility, and several other
MAC handling enhancements, using Ethernet Provider Backbone Bridging
combined with Ethernet VPN.  This work appears to provide significant
improvements to both network resource usage and in MAC address
manageability.

Overall the document is a bit thin on material on network management,
although the material describing the behavior of the mechanisms being
used in the context of different kinds of failures is quite good.

The document is very clearly written and the material describing
protocol operation/behavior is much appreciated.  The PBB-EVPN
mechanism appears to be an enormous win for very large data centers.

Passed the nits tool with only a warning about the publication year
not matching the current year.

This document was a pleasure to read.

Melinda

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Notification list changed to sajassi@cisco.com, lizho.jin@gmail.com, nabil.n.bitar@verizon.com, aisaac71@bloomberg.net, ssalam@cisco.com, draft-ietf-l2vpn-pbb-evpn.all@tools.ietf.org, wim.henderickx@alcatel-lucent.be, "Giles Heron" <giheron@cisco.com> from sajassi@cisco.com, lizho.jin@gmail.comlizhong, nabil.n.bitar@verizon.com, aisaac71@bloomberg.net, ssalam@cisco.com, draft-ietf-l2vpn-pbb-evpn.all@tools.ietf.org, wim.henderickx@alcatel-lucent.be, "Giles Heron" <giheron@cisco.com>

[Ballot comment]
Thanks for doing this without filling the document with 2119 key words.  I think it works well without them.

Two small comments:

1. Very minor: It probably would be best to change the document's title to "Provider Backbone Bridging Combined with Ethernet VPN (PBB-EVPN)".

2. I think the reference to [PBB] has to be normative; how is it not?

[Ballot comment]
There was a security directorate review from Catherine Meadows

> I don’t see any security concerns with this draft, but I do have some
> comments on the Security Considerations section.
> It is very short, and all it says that the security considerations in the
> EVPN draft apply directly to this draft. I assume that it is also the case
> that this draft introduces no new security considerations.  If so, you
> should say so, and you should also say why.  Also, I was wondering if
> the mechanisms introduced in this draft, by introducing a greater
> degree of organization in the delivery of MAC addresses, makes it
> easier to detect duplicated MACs, which were mentioned as a security
> risk in the Security Considerations of the EVPN draft.  If this is the case,
> it would be a good thing to mention here.
>
> I’d consider the draft somewhere between ready with nits and ready
> with issues.  I don’t see any real security issues here, just a Security
> Considerations section that needs to be expanded a little, but this
> seems to be a little more than what the secdir guidelines would call a
> nit.

This all seems a bit non-specific, but I have asked the authors to have a look and see whether they can generate a response and maybe suggest some text. At the same time, this document is not defining any new protocol per se, so I find it hard to suggest what extra could be written.

IESG/Authors/WG Chairs:

IANA has reviewed draft-ietf-l2vpn-pbb-evpn-09, which is currently in Last Call, and has the following comments:

We understand that, upon approval of this document, there are no IANA Actions that need completion.

While it is helpful for the IANA Considerations section of the document to remain in place upon publication, if the authors prefer to remove it, IANA doesn't object.

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

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (PBB-EVPN) to Proposed Standard

The IESG has received a request from an individual submitter to consider
the following document:
- 'PBB-EVPN'
  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 2015-01-26. 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 discusses how Ethernet Provider Backbone Bridging (PBB)
  can be combined with Ethernet VPN (EVPN) in order to reduce the
  number of BGP MAC advertisement routes by aggregating Customer/Client
  MAC (C-MAC) addresses via Provider Backbone MAC address (B-MAC),
  provide client MAC address mobility using C-MAC aggregation, confine
  the scope of C-MAC learning to only active flows, offer per site
  policies and avoid C-MAC address flushing on topology changes. The
  combined solution is referred to as PBB-EVPN.

Conventions

The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-l2vpn-pbb-evpn/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-l2vpn-pbb-evpn/ballot/


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

  http://datatracker.ietf.org/ipr/1908/

AD Review
=====
Sorry for sitting on this so long: a number of other things got in the
way.

I have done my usual AD review and don't have anything substantial. I'll
start the IETF last call (longer than 2 weeks because of the holiday
season) and you can fix any nits when convenient.

Thanks for the work,
Adrian

===

The RFC editor will require that the Contributors section is moved to
the end per the latest version of their style guide. I don't think you
need to do that now unless you have the document open for edits.

---

7.4.1 uses AC without expansion.

---

Section 9.3 was a good read :-)

---

Section 10 needs to point at Section 4 (not Section 3).
I don't really like the title of Section 10 - too much of a sales pitch.

Maybe...

10.  Assessing PBB-EVPN Against the Requirements

  In this section, we discuss how the PBB-EVPN solution addresses the
  requirements set forth in section 4 above.

Although I did wonder why the sub-sections in section 10 were not in
one-to-one correspondence with those in section 4.

---

The figures seem to be numbered 1, 2, 8, 7, 9 which may be seen as a
trifle idiosyncratic.

---

Ali and Lizhong had an email exchange with a nit to be fixed.

Draft Title: PBB-EVPN
Draft Name: draft-ietf-l2vpn-pbb-evpn-09

(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?

Standards Track.

This is the proper type of RFC as this is a key EVPN draft - providing enhanced
scaling by combining PBB and EVPN.  The type of RFC is indicated in the title page
header.

(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 discusses how Ethernet Provider Backbone Bridging (PBB)
  can be combined with Ethernet VPN (EVPN) in order to reduce the
  number of BGP MAC advertisement routes by aggregating Customer/Client
  MAC (C-MAC) addresses via Provider Backbone MAC address (B-MAC),
  provide client MAC address mobility using C-MAC aggregation, confine
  the scope of C-MAC learning to only active flows, offer per site
  policies and avoid C-MAC address flushing on topology changes. The
  combined solution is referred to as PBB-EVPN.

Working Group Summary:

  This document was an L2VPN Working Group document, and w reviewed
  in the working group through multiple iterations of the draft.

  The document passed WG last call in the L2VPN WG but is being advanced
  as AD Sponsored because that WG has closed.

Document Quality:

  The document is of roughly average length (22 pages).

  It is well structured, but needs to be read in the context of the base EVPN
  RFC (draft-ietf-l2vpn-evpn-11- should be an RFC soon), and requires
  knowledge of Ethernet bridging (including PBB). 

  The document has been through multiple revisions and is now sufficiently
  stable to progress to RFC, and more importantly to be used as a reference
  for creating interoperable implementations (in fact PBB EVPN has already
  been implemented by multiple vendors with more implementations in
  progress).

Personnel:

    Document Shepherd: Giles Heron (giheron@cisco.com)
    Area Director: Adrian Farrel (adrian@olddog.co.uk)

(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 thorough review of the text of version -07 of the draft,
  leading to the authors issuing version -08 with a large number of fixes.  The
  Document Shepherd then reviewed version -08 of the draft, following which the
  authors issued version -09 with more fixes.  The shepherd also did a scan through
  the mail archives and previous IETF meeting minutes to review debates on the draft.

(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.  From a security perspective the solution inherits the characteristics of the
  base EVPN draft (draft-ietf-l2vpn-evpn-11)

(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 against this draft.  However IPR was previously filed by
  Juniper, Cisco and Alcatel-Lucent (ID #1751, 1910, 2362 and 2363) against the base
  EVPN spec (draft-ietf-l2vpn-evpn-11).

(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 L2VPN WG consensus was previously noted as solid.  17 individuals
  supported the draft during WG LC, with nobody giving a differing opinion.
  There was much more discussion/debate around the base EVPN draft
  (draft-ietf-l2vpn-evpn-11)  than around this draft.

(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.

  No nits.

(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 required.

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

  Yes.  The Document Shepherd checked all this as part of the document review.

(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 - there is only one normative reference (to the base EVPN spec -
  draft-ietf-l2vpn-evpn-11, which is already with the IESG).

(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 - we would anticipate the base EVPN spec (draft-ietf-l2vpn-evpn-11) will be
  published before this doc (since it has been with the IESG for over 4 months).

(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 - no impact on status of existing RFCs.

(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).

  There are no IANA considerations beyond those noted in the base EVPN spec
  (draft-ietf-l2vpn-evpn-11).

(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 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 sections written in a formal language.

Notification list changed to sajassi@cisco.com, lizho.jin@gmail.comlizhong, nabil.n.bitar@verizon.com, aisaac71@bloomberg.net, ssalam@cisco.com, draft-ietf-l2vpn-pbb-evpn.all@tools.ietf.org, wim.henderickx@alcatel-lucent.be, "Giles Heron" <giheron@cisco.com> from sajassi@cisco.com, lizho.jin@gmail.comlizhong, nabil.n.bitar@verizon.com, aisaac71@bloomberg.net, ssalam@cisco.com, draft-ietf-l2vpn-pbb-evpn.all@tools.ietf.org, wim.henderickx@alcatel-lucent.be

Note added 'This document passed WG last call in the L2VPN working group and is being advanced as AD sponsored because that WG has now been closed.'