Datagram Transport Layer Security (DTLS) as Transport for Session Traversal Utilities for NAT (STUN)
draft-ietf-tram-stun-dtls-05

[Ballot comment]
- section 3, last para: the magic cookie is mentioned
here without introduction. Maybe add a ref to section
6 of 5389 if that's the right place?

- 4.1.1: "The  value MUST be used when using the
rules in Section 7.2.2 of [RFC5389] to verify the server
identity.  A STUN URI containing an IP address MUST be
rejected, unless the domain is provided by the same
mechanism that provided the STUN URI, and that this
domain name can be passed to the verification code." I
didn't get that sorry, can you explain what it means?
The "domain is provided by" bit confused me.  (Same for
end of 4.6.1)

- 4.2, 1st para: "not possible" hmm. Well, if the same
SDP stuff is sent to many places then it is, or if the
attacker can otherwise see the SDP stuff. Isn't that
common or won't it be common with WebRTC?

- 4.2, 2nd para: I'm not getting if you're encouraging
folks to use [I-D.thomson-rtcweb-ice-dtls] or not. Might
help to be clear about that. (I've not followed the
discussion on that draft though.)

- Section 5: Thanks!

[Ballot comment]
And one comment, along the lines of Kathleen's comment:

  transport.  But TLS-over-TCP is not an optimal transport when STUN is
  used for its originally intended purpose, which is to support
  multimedia sessions.  This sub-optimality primarily stems from the
  added latency incurred by the TCP-based head-of-line (HOL) blocking
  problem coupled with additional TLS buffering (for integrity checks).
  This is a well documented and understood transport limitation for
  secure real-time communications.

This HOL text reads weird. HOL is one issue, but the other issue is also retransmissions that are not need for real-time traffic but caused by TCP. Wouldn't it be sufficient to say, independent of TLS, that TCP is well-known not to be the first choice for transport real-time multimedia sessions?

[Ballot discuss]
I do not have any objection to the publication of the draft and this DISCUSS is just a blocker for IANA's ticket #767952 in order to clean up the port registry for STUN and TURN.

I will get back with some text proposal for the IANA considerations section.

[Ballot comment]
First of all, let me applause. I don't recall the last time a WG was ahead of schedule.
Jul 2014 Send draft adding DTLS as a transport for STUN/TURN to IESG for publication as Proposed Standard
draft-ietf-tram-stun-dtls


Confused by the abstract/footer. The former is "DTLS for STUN", while the latter is "TURN over DTLS".
Both should be aligned.
Wouldn't the abstract/footer be more accurate with "DTLS for STUN and TURN" or maybe "DTLS for ICE"?

[Ballot comment]
Thank you for addressing the SecDir review comments.  I'll look for the update as many good points were made and discussed with the editors.  This is a placeholder to watch for the corrections identified in the review.  The discussion looks good so far, thanks.

Could a reference be added for the two items in this description of the Introduction?
  This sub-optimality primarily stems from the
  added latency incurred by the TCP-based head-of-line (HOL) blocking
  problem coupled with additional TLS buffering (for integrity checks).

IESG/Authors/WG Chairs:

IANA has reviewed draft-ietf-tram-stun-dtls-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 has questions about one of the actions requested in the IANA Considerations section of this draft document.

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

First, in the S-NAPTR Application Protocol Tags subregistry of the Straightforward-NAPTR (S-NAPTR) Parameters registry located at:

http://www.iana.org/assignments/s-naptr-parameters/

a new S-NAPTR application protocol tag will be registered as follows:

Tag: turn.dtls
Reference: [ RFC-to-be ]

Second, in the Service Names and Transport Protocol Port Numbers/Service Name and Transport Protocol Port Number registry located at:

http://www.iana.org/assignments/service-names-port-numbers/

two existing service names/port numbers are to be uppdated.

NOTE/Question: IANA notes that stuns has a registered port for TCP (5349) and turns has a registered port for TCP (also 5349) and these share the port number with stun-behaviors.  This document is to update the Description
of the two UDP transports from "Reserved for a future enhancement of STUN" and "Reserved for a future enhancement of TURN" to "STUN over DTLS"
and "TURN over DTLS", respectively.  The service name/port number registry is managed by IESG designated Expert Review team.  We will send this request
to the team leader for review and advices. 

In that event the entries would be changed to the following:

Service Name: stuns
Port Number: 5349
Transport Protocol: UDP
Description: STUN over DTLS
Reference: [ RFC-to-be ]

Service Name: turns
Port Number: 5349
Transport Protocol: UDP
Description: TURN over DTLS
Reference: [ RFC-to-be ]

QUESTIONs for authors:  This document is to update RFCs, 5389 and 5928
(if approved).  Are the authors intended to remove the original/listed
RFC5389 for stuns?  How does this document remove/update RFC5766 for
turns?  Has the modification of the turns registration confirmed by
authors of RFC5766?

NOTE: RFC6335 said:

  For assignments done through
      RFCs published via the "IETF Document Stream" [RFC4844], the
      Contact will be the IETF Chair .

Please update the text "Contact:  Marc Petit-Huguenin" in the IC section.

IANA understands that these two 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.

The following Last Call announcement was sent out:

From: The IESG
To: IETF-Announce
CC:
Reply-To: ietf@ietf.org
Sender:
Subject: Last Call:  (Datagram Transport Layer Security (DTLS) as Transport for Session Traversal Utilities for NAT (STUN)) to Proposed Standard


The IESG has received a request from the TURN Revised and Modernized WG
(tram) to consider the following document:
- 'Datagram Transport Layer Security (DTLS) as Transport for Session
  Traversal Utilities for NAT (STUN)'
  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 2014-06-25. 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 specifies the usage of Datagram Transport Layer
  Security (DTLS) as a transport protocol for Session Traversal
  Utilities for NAT (STUN).  It provides guidances on when and how to
  use DTLS with the currently standardized STUN Usages.  It also
  specifies modifications to the STUN URIs and TURN URIs and to the
  TURN resolution mechanism to facilitate the resolution of STUN URIs
  and TURN URIs into the IP address and port of STUN and TURN servers
  supporting DTLS as a transport protocol.




The file can be obtained via
http://datatracker.ietf.org/doc/draft-ietf-tram-stun-dtls/

IESG discussion can be tracked via
http://datatracker.ietf.org/doc/draft-ietf-tram-stun-dtls/ballot/


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

> 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)?

Proposed Standard

> Why is this the proper type of RFC?

Because it defines a new transport protocol for STUN.

> Is this type of RFC indicated in the title page header?

Yes.

> (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
>
>  Relevant content can frequently be found in the abstract
>  and/or introduction of the document. If not, this may be
>  an indication that there are deficiencies in the abstract
>  or introduction.
>
> Working Group Summary
>
>  Was there anything in WG process that is worth noting? For
>  example, was there controversy about particular points or
>  were there decisions where the consensus was particularly
>  rough?
>
> Document Quality
>
>  Are there existing implementations of the protocol? Have a
>  significant number of vendors indicated their plan to
>  implement the specification? Are there any reviewers that
>  merit special mention as having done a thorough review,
>  e.g., one that resulted in important changes or a
>  conclusion that the document had no substantive issues? If
>  there was a MIB Doctor, Media Type or other expert review,
>  what was its course (briefly)? In the case of a Media Type
>  review, on what date was the request posted?
>
> Personnel
>
>  Who is the Document Shepherd? Who is the Responsible Area
>  Director?

Technical Summary

  This document specifies the usage of Datagram Transport Layer Security (DTLS)
  as a transport protocol for Session Traversal Utilities for NAT (STUN).  It
  also specifies modifications to the STUN URIs and TURN URIs and to the TURN
  resolution mechanism to facilitate the resolution of STUN URIs and TURN URIs
  into the IP address and port of STUN and TURN servers supporting DTLS as a
  transport protocol.

Working Group Summary

  This is the first document produced by the TRAM working group. No controversy
  was experienced. Many different people have provided feedback and guidance.
  Some of the harder questions:

  - What cipher suite to specify as mandatory?
  - How to ensure that a hostname is available for certificate validation?

Document Quality

  Two existing implementations are listed in section 5. RTCWEB implementers have
  demonstrated interest.

  This draft has continuously been reviewed by many different people throughout
  its history.  While the TRAM WG is composed primarily of NAT traversal
  experts, TLS experts have been solicited and have provided very helpful
  feedback, particularly at the IETF 89 meeting.

Personnel

  Document Shepherd: Simon Perreault
  Responsible Area Director: Spencer Dawkins

> (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.

Full review + nit checker.

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

No 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.

TLS experts have been solicited and have provided very helpful feedback,
particularly at the IETF 89 meeting.

> (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 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 disclosure has been filed.

> (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? 

Consensus represents the whole WG.

> (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 threats have been made.

> (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 have been found.

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

No such reviews were done.

> (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?

All normative references are to RFCs.

> (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.

There are no downward normative references.

> (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.

Revision -03 (the current revision as of this write-up writing) added this header:

Updates: 5389, 5928 (if approved)

A sentence needs to be added at the end of the abstract:

Abstract

  This document specifies the usage of Datagram Transport Layer
  Security (DTLS) as a transport protocol for Session Traversal
  Utilities for NAT (STUN).  It provides guidances on when and how to
  use DTLS with the currently standardized STUN Usages.  It also
  specifies modifications to the STUN URIs and TURN URIs and to the
  TURN resolution mechanism to facilitate the resolution of STUN URIs
  and TURN URIs into the IP address and port of STUN and TURN servers
  supporting DTLS as a transport protocol. ***It updates RFCs 5389 and 5928.***

> (17) Describe the Document Shepherd's review of the IANA considerations
> section, especially with regard to its consistency with the body of the
> document.

Careful review.

> Confirm that all protocol extensions that the document makes
> are associated with the appropriate reservations in IANA registries.

I confirm.

> Confirm that any referenced IANA registries have been clearly
> identified.

I confirm.

> 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 newly created IANA registries.

> (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 IANA registries are requested.

> (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.

None.