Last Call Review of draft-petithuguenin-behave-turn-uris-05
review-petithuguenin-behave-turn-uris-05-secdir-lc-tsou-2013-08-22-00

Dear all,

I have reviewed this document as part of the security directorate's ongoing
effort to review all IETF documents being processed by the IESG.

These comments were written primarily for the benefit of the security area
directors.  Document editors and WG chairs should treat these comments just
like any other last call comments.



Summary: This document is almost ready for publication aiming for Standards
Track.



This document defines two URI schemes to provision the TURN Resolution
Mechanism.



This document defines TURN Server URI syntax. It considers UDP/TCP/TLS
scenarios, facilitating applications like WEBRTC to use TURN Server to
accomplish NAT Traversal.



Major issues: None



Minor issues:



1. The authors define the syntax for the turn/turns URI in ad hoc fashion,
copying definitions from RFC 3986 rather than using RFC 3986 directly. The
justification is that there is no need for hierarchy in the turn/turns URI.



In fact, hierarchy is introduced only within the path component described by
RFC 3986. The turn/turns URI as defined in this document is achieved by use of
the RFC 3986 form:



scheme ":" hier-part [ "?" query ] [ "#" fragment ]



with the following specific rules:



  hier-part consists of the authority part and an empty path



  userinfo and the succeeding '@' MUST be omitted from authority



  the fragment portion is not present.



It is strongly recommended that this formulation be used, to bring the document
into line with RFC 3986. Note that this implies adding double slash '//' after
the scheme.



2. The Security Considerations section correctly makes reference to RFC 5928,
but perhaps does not make it clear that RFC 5928 Section 5 is essential
reading. Could I suggest:



"Security considerations for the resolution mechanism are discussed in Section
5 of [RFC5928]. Note that that section contains normative text defining
authentication procedures to be followed by turn clients when TLS is used."





Thank you,

Tina