Hi all:

I have performed an Operations Directorate review of
    draft-ietf-straw-b2bua-stun-05

  "Session Initiation Protocol (SIP) Back-to-Back User Agents (B2BUAs)
   are often designed to be on the media path, rather than just
   intercepting signaling.  This means that B2BUAs often act on the
   media path leading to separate media legs that the B2BUA correlates
   and bridges together.  When acting on the media path, B2BUAs are
   likely to receive Session Traversal Utilities for NAT (STUN) packets
   as part of Interactive Connectivity Establishment (ICE) processing.

   This document defines behavior for a B2BUA performing ICE processing.
   The goal of this draft is to ensure that B2BUAs properly handle STUN
   messages received as part of the ICE procedures used for NAT and
   Firewall traversal of multimedia sessions."

- - - -

At first sight this draft this draft contains a lot of SIP-related
acronyms.  However, most of them are clearly explained, and the intent
of the draft is clear.  In particular, the draft spells out exactly
how Back-to-Back User Agents must behave in the situations outlined
in its abstract (above).  I can see that this hasn't been clear in
the past, so this draft will clearly be useful.

Overall, a good document, ready for publication.

One question:

s4.3, first para: /but does not otherwise require it can do/
   I don't think this is clear - do you mean "require it to do"
   or "require that it can do"?  Can you re-word this to make it
   clearer exactly what is intended?

A few typos:

s4.1, para 2: s/behaviour B2BUA's MUST follow/behaviour B2BUAs MUST follow/
              /(ice-frag and ice-pwd / has no closing parenthesis

s4.2, third bullet: s/B2BUAs candidates/B2BUA's candidates/

p8, 3rd-to-last bullet of s4.2:
        s/and have two ICE contexts/and has two ICE contexts/

Cheers, Nevil
Co-chair, EMAN WG
Ex Co-chair, IPFIX WG (now closed)

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 Nevil Brownlee                          Computer Science Department
 Phone: +64 9 373 7599 x88941             The University of Auckland
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