Subject: [SAFE] SAFE BoF in Vancouver

From: Colin Perkins <[email-masked]>
Date: Fri, 16 Nov 2007 13:59:53 +0000

The following BoF has been proposed for the Vancouver IETF. There is  
a mailing list <[email-masked]> for discussion.

Colin

SAFE - Self-Address Fixing Evolution BoF
----------------------------------------

Chairs:
   Colin Perkins  ([email-masked])
   Markus Isomaki ([email-masked])

Mailing list:
   https://www1.ietf.org/mailman/listinfo/safe

Various NAT hole-punching techniques such as IPsec NAT traversal,  
Teredo, and STUN/ICE send periodic UDP keep-alive messages to keep  
their NAT binding alive.

However, a drawback of these techniques is their chattiness which is  
a result of the host application not knowing the NAT's binding  
lifetime (IPsec NAT traversal, STUN/ICE) or because the application  
is unable to extend the lifetime of the NAT's binding (Teredo).  The  
endpoint has to send periodic packets which consume power on battery  
powered devices, consume network bandwidth, and place an unnecessary  
load on servers.

There are two approaches to resolve the problem of chattiness. The  
first is to interact directly with the NAT using a NAT control  
protocol. Several of these protocols exist which unfortunately have  
different drawbacks:

   * incremental deployment is not possible with MIDCOM, NSIS-NSLP,
     UPnP IGD, or NAT-PMP.  With all of these protocols, both the NAT
     and the endpoint have to support the same protocol
   * nested NATs are not possible with UPnP IGD or NAT-PMP
   * topology awareness is required of MIDCOM
   * security must be established between the controlling entity and
     the NAT for MIDCOM and NSIS-NSLP
   * UPnP IGD uses broadcasts packets and NAT-PMP expects the NAT to be
     the default gateway; neither work well on routed networks

The second approach is to empirically test the NAT's binding  
lifetime, as done by Teredo. This can optimise the keep-alive traffic  
based on the NAT's binding lifetime, but cannot extend the duration  
of the binding lifetime. Also, empirical testing does not always give  
reliable results due to varying behaviour of NAT and firewall  
implementations.

This BoF is intended to discuss a newly-proposed technique for using  
STUN to discover, query and control firewalls and NATs, that can  
eliminate UDP
keep-alive traffic. The BoF will review the problem space and  
existing work, and decide if there is a need for new work in the  
area, and if the IETF is an appropriate home for that work. The  
intent is not to form a new working group at this time, but to gauge  
interest in work in this area, and consider an appropriate future  
home for that work.

Agenda:
    Introduction ...................................... (Chairs, 10)
    Problem statement and scope ......................... (Wing, 15)
    Survey of existing work ........................... (Barnes, 30)
       draft-eggert-middlebox-control-survey-01.txt
    NAT/Firewall control with STUN ...................... (Wing, 15)
       draft-wing-behave-nat-control-stun-usage-05.txt
    Discussion ................................................ (20)
    Future directions ................................. (Chairs, 30)

--
version: 1.5, 16-Nov-2007

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