Behavior Engineering for Hindrance Avoidance (behave)
-----------------------------------------------------

 Charter
 Last Modified: 2006-07-11

 Current Status: Active Working Group

 Chair(s):
     Dan Wing  <dwing@cisco.com>

 Transport Area Director(s):
     Magnus Westerlund  <magnus.westerlund@ericsson.com>
     Lars Eggert  <lars.eggert@netlab.nec.de>

 Transport Area Advisor:
     Magnus Westerlund  <magnus.westerlund@ericsson.com>

 Mailing Lists: 
     General Discussion:ietf-behave@list.sipfoundry.org
     To Subscribe:      ietf-behave-request@list.sipfoundry.org
         In Body:       with subscribe in body
     Archive:           http://list.sipfoundry.org/archive/ietf-behave

Description of Working Group:

Given the current near-universal deployment of NATs (Network Address
Translators) in the public Internet, the lack of standards for NAT 
behavior has given rise to a crisis. While it is widely acknowledged 
that NATs create problems for numerous Internet applications, our 
inability to describe precisely what a NAT is or how it behaves leaves 
us few solutions for compensating for the presence of NATs.

The behavior of NATs varies dramatically from one implementation to 
another. As a result it is very difficult for applications to predict 
or discover the behavior of these devices. Predicting and/or 
discovering the behavior of NATs is important for designing 
application protocols and NAT traversal techniques that work reliably 
in existing networks. This situation is especially problematic for end-
to-end interactive applications such as multiuser games and 
interactive multimedia.

NATs continue to proliferate and have seen an increasing rate of 
deployment. IPv6 deployments can eliminate this problem, but there is 
a significant interim period in which applications will need to work 
both in IPv4 NAT environments and with the IPv6 to IPv4 transition 
mechanisms.

This working group proposes to generate requirements documents and best
current practices to enable NATs to function in as deterministic a 
fashion as possible. It will consider what is broken by these devices 
and document approaches for characterizing and testing them. The NAT 
behavior practices will be application independent.

The group will also advise on how to develop applications that 
discover and reliably function in environments with NATs that follow 
the best current practices identified by this working group. This will 
include the development of protocol-independent toolkits usable by 
application protocols for NAT traversal. This will include a revision 
of RFC 3489 for NAT binding discovery and a relay protocol that 
focuses on security.

The work will be done with the goal of encouraging eventual migration 
to IPv6 and compliance with the UNSAF [RFC 3424] considerations. It 
will not encourage the proliferation of NATs.

The behavior that will be considered includes IP fragmentation and
parameters that impact ICMP, UDP, TCP, IGMP, MLD, and multicast. The
proposed WG will coordinate with v6ops, midcom and nsis. The work is 
largely limited to examining various approaches that are already in 
use today and providing suggestions about which ones are likely to 
work best in the internet architecture.

 Goals and Milestones:

   Done         Submit BCP that defines unicast UDP behavioral requirements for 
                NATs to IESG 

   Aug 2006       Submit revision of RFC 3489 to IESG 

   Sep 2006       Submit BCP that defines multicast UDP behavioral requirements 
                for NATs to IESG 

   Oct 2006       Submit relay protocol to IESG 

   Oct 2006       Submit IPv6 relay protocol to IESG 

   Dec 2006       Submit a BCP that discusses protocol design techniques for 
                using the existing set of NAT traversal approaches to IESG 

   Mar 2007       Submit a BCP that defines TCP behavioral requirements for NATs 
                to IESG 

   Mar 2007       Submit a BCP that defines ICMP behavioral requirements for NATs 
                to IESG 

   Apr 2007       Close WG or recharter 


 Internet-Drafts:

Posted Revised         I-D Title   <Filename>
------ ------- --------------------------------------------
Oct 2004 Jul 2006   <draft-ietf-behave-rfc3489bis-04.txt>
                Simple Traversal Underneath Network Address Translators (NAT) 
                (STUN) 

Jan 2005 Jun 2006   <draft-ietf-behave-nat-udp-07.txt>
                NAT Behavioral Requirements for Unicast UDP 

May 2005 Jun 2006   <draft-ietf-behave-multicast-02.txt>
                Multicast Requirements for a Network Address Port Translator 
                (NAPT) 

Feb 2006 Jun 2006   <draft-ietf-behave-tcp-01.txt>
                NAT Behavioral Requirements for TCP 

Mar 2006 Jun 2006   <draft-ietf-behave-turn-01.txt>
                Obtaining Relay Addresses from Simple Traversal of UDP Through 
                NAT (STUN) 

Mar 2006 Mar 2006   <draft-ietf-behave-turn-ipv6-00.txt>
                Traversal Using Relay NAT (TURN) Extension for IPv4/IPv6 
                transition 

May 2006 May 2006   <draft-ietf-behave-nat-icmp-00.txt>
                NAT Behavioral Requirements for ICMP protocol 

 Request For Comments:

  None to date.