Mapping of Address and Port with Encapsulation (MAP-E)
draft-ietf-softwire-map-13

[Ballot comment]
I don't have any specific objection to this document. I agree with others that there are too many options and potential solutions being published. While there is a good chance that the market will decide and winnow this down to just a very few practical solutions, I believe the IETF (and specifically the Softwire working group) is letting down the industry. Vendors will be unclear which solutions to implement and operators are unlikely to give early direction. This will result in multiple implementations that either do not interoperate or that increase the net cost of equipment. And in the end, who pays?

I wish more effort had gone into reducing the options.

[Ballot comment]
[updated with one question at the end of the ballot]

I am balloting no objection on the grounds that this document has been reviewed by the WG and the IETF community at large and apparently "passed" the last calls in terms of having rough consensus.

However, the proposed solution looks personally to me like a big hack or in other words this document is creating a cross IP version protocol address translator (including using transport protocols).
Actually, the whole work of the softwire working group should be reconsidered from an architectural view. Is this really the long term solution to get the IP transition right or is this just creating the next headache in five years as something out of the networking layer and the transport layer is mixed together as an IPv6 address?

Adding another question:
RFC6346 A+P is used throughout the document and I believe an implementer has to read RFC6346 and understand the A+P sharing mechanism in order to get the implementation of this draft right. Or isn't any knowledge about RFC 6346 required?

[Ballot comment]
This is perhaps more a comment for the ADs, but it seems that the mechanism specified in this document provides a high degree of configurability in terms of the size of port sets without providing any guidance or explanation about the impact on application stability/breakage of choosing different set sizes. Is there a document somewhere in the softwire document suite that provides this background or advice to service providers about minimizing application impact when choosing port set sizes? RFC 6269 points out the problems, but doesn't provide any detail about how tuning the kinds of knobs available in this spec may affect applications one way or the other. If such a document does not exist, it seems like at least the deployment of the mechanism specified here, if not other variations that make use of restricted port sets, would benefit from it.

[Ballot comment]
I am balloting no objection on the grounds that this document has been reviewed by the WG and the IETF community at large and apparently "passed" the last calls in terms of having rough consensus.

However, the proposed solution looks personally to me like a big hack or in other words this document is creating a cross IP version protocol address translator (including using transport protocols).
Actually, the whole work of the softwire working group should be reconsidered from an architectural view. Is this really the long term solution to get the IP transition right or is this just creating the next headache in five years as something out of the networking layer and the transport layer is mixed together as an IPv6 address?

[Ballot comment]
I am balloting no objection on the grounds that this document has been reviewed by the WG and the IETF community at large and apparently "passed" the last calls in terms of having rough consensus.

However, the proposed solution looks personally to me like a big hack or in other words this document is creating a cross IP version protocol address translator (including using transport protocols).
Actually, the whole work of the softwire working group should be reconsidered from an architectural view. Iis this really the long term solution to get the IP transition right or is this just creating the next headache in five years as something out of the networking layer and the transport layer is mixed together as an IPv6 address?

[Ballot discuss]
The SecDir review raised a few points that should be discussed.  I didn't see a response to the message from Brian and will highlight his findings here as well as include a link to the thread for the editors to respond to this review:
http://www.ietf.org/mail-archive/web/secdir/current/msg05147.html

The Security Considerations section lists several attacks. The text seems reasonable. It would be helpful if there was a reference to "Address-Dependent Filtering", which might be RFC 4787.

The main risk to the mapping method seems to be a threat of overlapping address mappings, such that return packets are delivered to the wrong user. This would be a security consideration if users received other users traffic. The algorithm seems designed to avoid this, at least Appendix B indicates this as a requirement. If this is in fact believed to guarantee non-overlapping mappings then this should be stated in this section. The only statement I can find is in Section 5.1, where it is stated that "Different PSIDs guarantee non-overlapping port-sets." But if I'm not mistaken, the PSIDs are also computed so this might not actually be a guarantee. If there was a proof of correctness ensuring that a correct implementation will ensure non-overlapping mappings then this should be mentioned as well.

[Ballot comment]
I find it a dis-service to the community for the softwire WG to put forth multiple solutions that solve essentially the same problem (https://mailarchive.ietf.org/arch/msg/ietf/jcscmIHmAQSvXLAlLLvfhnC2P8A).  I believe the confusion caused by a myriad of solutions in this space, regardless of whether they are Standards Track or Experimental, will adversely impact vendors, operators, and end-users.  My only hope is that this confusion will speed up the transition to IPv6-only operations within the affected networks.

IESG/Authors/WG Chairs:

IANA has reviewed draft-ietf-softwire-map-10, 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
CC:
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Mapping of Address and Port with Encapsulation (MAP)) to Proposed Standard


The IESG has received a request from the Softwires WG (softwire) to
consider the following document:
- 'Mapping of Address and Port with Encapsulation (MAP)'
  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 2014-10-10. 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


  This document describes a mechanism for transporting IPv4 packets
  across an IPv6 network using IP encapsulation, and a generic
  mechanism for mapping between IPv6 addresses and IPv4 addresses and
  transport layer ports.




The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-softwire-map/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-softwire-map/ballot/


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

  http://datatracker.ietf.org/ipr/2049/

(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. This document documents a scheme used to provide
residual IPv4 service over IPv6 access networks. The document
describes an algorthmic mapping between IPv4 addresses (and
potentially ports) and IPv6 addresses, as well as a mechanism for
encapsulating IPv4 datagrams over IPv6.

(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 a mechanism for transporting IPv4 packets
across an IPv6 network using IP encapsulation, and a generic mechanism
for mapping between IPv6 addresses and IPv4 addresses and transport
layer ports.The mapping scheme described here supports encapsulation
of IPv4 packets in IPv6 in both mesh and hub and spoke topologies,
including address mappings with full independence between IPv6 and
IPv4 addresses.  This document describes delivery of IPv4 unicast
service across an IPv6 infrastructure.  A companion document describes
the DHCPv6 options necessary for provisioning of MAP.

Working Group Summary:

The working group had active discussion on the draft and the current
text of the draft is representative of the consensus of the working
group. This document and the lightweight 4over6 document are closely
related and it led to a lot of friction in the working group.

MAP is capable of either providing independence between IPv6 subnet
prefix and IPv4 address or, alternatively, reducing the amount of
centralized state using rules to express IPv4/IPv6 address mappings.
This introduces an algorithmic relationship between the IPv6 subnet
and IPv4 address.  This relationship also allows the option of direct,
meshed connectivity between users.

Lightweight 4over6, on the other hand, is a solution designed
specifically for complete independence between IPv6 subnet prefix and
IPv4 address with or without IPv4 address sharing.  This is
accomplished by maintaining state for each softwire (per-subscriber
state) in the central lwAFTR and a hub-and-spoke forwarding
architecture.


Document Quality:

The document has received adequate review. The Document Shepherd has
no concerns about the depth or breadth of these reviews. There are
several interoperable implementations of the scheme and they have been
demonstrated and tested during the IETF meetings.

Personnel:

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

Suresh Krishnan is the document shepherd. Ted Lemon is the responsible
AD.

(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 draft and finds that it is ready
to advance to the IESG. All issues that were raised in the working group
last calls have been addressed.

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

No. The document shepherd has 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.

(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 significant overlap between the stateless softwire
solutions. The WG has discussed this overlap and the current document
set (along with the document dracks) are the result of working group
consensus to do so.

(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.

Yes. https://datatracker.ietf.org/ipr/2049/. There were some
discussions in the WG about whether this ipr also affected other
drafts such as the 4rd solution but there was no concern about the ipr
on the MAP-E draft itself.

(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?

There is strong WG consensus behind 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.)

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 errors were found on the ID nits check. The document does use
non-5735 addresses (1.2.3.4) in addition to the 5735 addresses
(192.0.2.18) for an example. I believe it helps readability as it
translates easier into hex (0x01020304). If the IESG feels strongly
about this I will ask the authors to move into another documentation
block.

(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).

The document requires no IANA actions.

(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