Subject: [tsv-area] BOF request under consideration: SAFE

From: Magnus Westerlund <[email-masked]>
Date: Mon, 08 Oct 2007 17:09:00 +0200

Hi,

We ADs have received a request for a BOF in Vancouver: SAFE -
Self-Address Fixing Evolution. See description below. I would appreciate
any feedback on this. For public discussion please use the SAFE mailing
list.

Post: [email-masked]
Subscribe: https://www1.ietf.org/mailman/listinfo/safe

Draft:
http://www.ietf.org/internet-drafts/draft-wing-behave-nat-control-stun-usage-03.txt

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

Chairs:
  TBD

ICE and its companion protocol STUN have been successfully deployed on
the Internet for NAT traversal.  ICE and STUN have several characteristics
which contribute to their success:

  1. incremental deployment.  ICE and STUN are functional without any
     modifications to existing NATs.
  2. nested NATs.  ICE and STUN work when there are multiple NATs
     between a host and the Internet.
  3. topology unaware.  ICE and STUN are not configured with
     information about NATs, firewalls, or their locations -- only
     with the IP address of a server on the Internet.
  4. simple security model.  If a host behind a NAT is allowed to send
     a packet across the NAT, it is allowed to receive a response.
  5. works on routed networks, which allows operation in both
     enterprise networks and home networks.

Other NAT traversal protocols do not share these characteristics,
which hinders their widespread deployment.  Specifically,

  * incremental deployment is not possible with MIDCOM, NSIS-NSLP,
    UPnP, or Bonjour.  With all of these protocols, both the NAT
    and the endpoint have to support the same protocol.
  * nested NATs are not possible with UPnP or Bonjour.
  * topology awareness is required of MIDCOM.
  * security must be established between the controlling entity
    and the NAT for MIDCOM and NSIS-NSLP.
  * Both UPnP and Bonjour use broadcast packets which don't work
    well on routed networks.

However, a drawback of ICE/STUN is its chatty keepalive traffic,
which is a result of STUN not knowing the binding lifetime of its
on-path NATs.  This chattiness causes a burden on servers and
consumes network bandwidth, which is especially critical on wireless
networks.  It is desirable to reduce this chattiness while still
retaining the important characteristics of STUN and ICE.

This BoF is intended to discuss one proposed technique,
draft-wing-behave-nat-control-stun-usage, which nearly eliminates
STUN's keepalive chatter and still preserves the desirable
characteristics of STUN/ICE.

The purpose of this BoF is to create a working group for this effort.

Agenda:
  Introduction, Agenda ....................................  5
  Summary of existing NAT traversal techniques ............ 40
   (UPnP, NAT-PMP/Bonjour, MIDCOM techniques, NSIS-NSLP, ICE)
  draft-wing-behave-nat-control-stun-usage ................ 40
  Q&A ..................................................... 25
                                                    ----------
                                                    total: 110

Cheers

Magnus Westerlund

IETF Transport Area Director & TSVWG Chair
----------------------------------------------------------------------
Multimedia Technologies, Ericsson Research EAB/TVM/M
----------------------------------------------------------------------
Ericsson AB                | Phone +46 8 4048287
Torshamsgatan 23           | Fax   +46 8 7575550
S-164 80 Stockholm, Sweden | mailto: [email-masked]
----------------------------------------------------------------------

---

From: [email-masked]
Date: Mon, 8 Oct 2007 12:52:16 -0400

Magnus,

IKE and IKEv2 NAT Traversal for IPsec (also widely deployed, e.g.,
I believe my VPN client is using it to send this message ;-) ...)
are not on the list of related technologies.  This might be an
omission, but I suspect that the (assumed) problem definition
for SAFE may exclude IPsec (e.g., IKE and IKEv2 have a different
security model for which a server like the STUN server may be
problematic).  This should be clarified.

Thanks,
--David
----------------------------------------------------
David L. Black, Senior Technologist
EMC Corporation, 176 South St., Hopkinton, MA  01748
+1 (508) 293-7953             FAX: +1 (508) 293-7786
[email-masked]        Mobile: +1 (978) 394-7754
----------------------------------------------------

> -----Original Message-----
> From: Magnus Westerlund [mailto:[email-masked]] 
> Sent: Monday, October 08, 2007 11:09 AM
> To: TSV Area; Behave WG; mmusic (E-mail)
> Subject: [tsv-area] BOF request under consideration: SAFE
> 
> Hi,
> 
http://www.ietf.org/internet-drafts/draft-wing-behave-nat-control-stun-u
sage-03.txt

---

From: "Dan Wing" <[email-masked]>
Date: Tue, 9 Oct 2007 12:43:04 -0700

Hi, David.  

I am aware of IPsec-over-UDP (RFC3947, RFC3948), but I'm not sure 
how it applies in a comparison of MIDCOM, UPnP, NSIS-NSLP, 
NAT-PMP, and STUN/ICE.

-d

> From: [email-masked] [mailto:[email-masked]] 
> Sent: Monday, October 08, 2007 9:52 AM
> To: [email-masked]; [email-masked]; [email-masked]
> Cc: [email-masked]
> Subject: RE: [tsv-area] BOF request under consideration: SAFE
> 
> Magnus,
>

---

From: [email-masked]
Date: Tue, 9 Oct 2007 18:10:54 -0400

Dan,

Section 2.23 of RFC 4306 is also part of this technology.

I'm also not sure how any of this applies to the BoF.  The
BoF proposal should probably contain a few sentences to
say that IPsec NAT Traversal is a different problem,
including a brief explanation of why it's different, and
state that therefore it's outside the scope of the BoF.

Thanks,
--David

> From: Dan Wing [mailto:[email-masked]] 
> Sent: Tuesday, October 09, 2007 3:43 PM
> To: Black, David
> Cc: [email-masked]; [email-masked]; [email-masked]

---

From: "Dan Wing" <[email-masked]>
Date: Tue, 9 Oct 2007 17:04:14 -0700

Thanks for the pointer.  I read RFC4306 section 2.23, and IKE
(and IPsec) could benefit from reduced keepalive traffic if it
knew how often to send the keeaplive.  It could learn or adjust
the keepalive interval using UPnP, STUN Control, NAT-PMP, etc.

So, the IPsec/IKE UDP-based NAT traversal technique is another 
thing that could benefit from knowing the NAT binding lifetime 
-- much like SIP-Outbound benefits from knowing the NAT binding 
lifetime and is able to reduce keepalive traffic.

So, I think I'll mention this reduction of IPsec keepalive 
traffic is another benefit that STUN Control could bring.  In
that light, I added the following to the soon-to-be-published
draft-wing-behave-nat-control-stun-usage-04.txt:

   2.4.  Reduce IPsec keepalive messages

   STUN Control is also able to reduce keepalive traffic for non-STUN
   protocols.  In Section 4 of [RFC3948], it is suggested that IPsec
   keepalive packets be sent every 20 seconds if an on-path NAT is
   detected.  If a host and its NAT were to implement STUN Control, the
   host can query and control the NAT's binding lifetime, and thus
   reduce the NAT keepalive traffic.  This reduction in keepalive
   traffic would slightly reduce the load on its IPsec concentrator.

-d

> Sent: Tuesday, October 09, 2007 3:11 PM
> To: [email-masked]

---

From: <[email-masked]>
Date: Thu, 11 Oct 2007 13:22:27 +0300

Hi,

STUN control would be able to reduce keepalive traffic for all UDP-based
applications or UDP encapsultated protocols. In addition to IPSec/IKE,
there are also other protocols such as DSMIPv6 and Teredo, that use UDP
encapsulation to work through NATs. So, one clear use case for STUN
control is to optimize how any of those protocols work through NATs.

IPSec VPNs are of special interest as they are already widely used. For
instance you can try to run a VPN connection on any handheld device in
any wide-area radio network (CDMA EV-DO, WCDMA, EDGE, WiMAX) and see how
long the battery on the device will last. Most of the battery is
consumed by NAT keepalives sent every 20 to 120 seconds while there is
no real traffic to send. Optimizing this should be of interest to: 
a) users (get their work done before the battery dies) 
b) enterprises (allow their employees get their work done while on the
road) 
c) handheld device vendors (make VPN usable in the devices) 
d) wireless operators (make VPN usable in their network) 
e) NAT vendors (sell boxes that meet the reqs of the above groups)

In the long run any IPv6 over IPv4 solutions might also become necessary
for mobile hosts and they will face the same UDP NAT problem. 

Markus

>From: ext Dan Wing [mailto:[email-masked]] 
>Sent: 10 October, 2007 03:04
>To: [email-masked]
>Cc: [email-masked]; [email-masked]
>Subject: [SAFE] RE: [tsv-area] BOF request under consideration: SAFE
>
>knew how often to send the keeaplive.  It could learn or 
>adjust the keepalive interval using UPnP, STUN Control, NAT-PMP, etc.
>
>-- much like SIP-Outbound benefits from knowing the NAT 
>binding lifetime and is able to reduce keepalive traffic.
>
>> I'm also not sure how any of this applies to the BoF.  The BoF 
>> proposal should probably contain a few sentences to say that 
>IPsec NAT 
>> Traversal is a different problem, including a brief 
>explanation of why 
>> it's different, and state that therefore it's outside the 
>scope of the 
>> BoF.
>> 
>> Thanks,
>> --David
>NAT-PMP, 
>> > and STUN/ICE.
>> > > omission, but I suspect that the (assumed) problem 
>definition for 
>> > > SAFE may exclude IPsec (e.g., IKE and IKEv2 have a different 
>> > > David L. Black, Senior Technologist EMC Corporation, 176 South 
>> > > St., Hopkinton, MA  01748
>_______________________________________________
>SAFE mailing list
>[email-masked]
>https://www1.ietf.org/mailman/listinfo/safe
>