Subject: [Softwires] ALG section in draft-ietf-softwire-dual-stack-lite-06

From: "Dan Wing" <[email-masked]>
Date: Wed, 23 Feb 2011 08:19:14 -0800

http://tools.ietf.org/html/draft-ietf-softwire-dual-stack-lite-06 says:

   8.3. Application Level Gateways (ALG)

   The AFTR should only perform a minimum number of ALG for the classic
   applications such as FTP, RTSP/RTP, IPsec and PPTP VPN pass-through
   and enable the users to use their own ALG on statically or
   dynamically reserved ports instead.

Comments:

* To my knowledge, this would be the first time IETF suggests using an ALG
in a NAT44 in a standards-track document.

* Both IPsec and PPTP are protocols, not applications.  IPsec is 50
(assuming you mean IPsec ESP, which I'm sure is what was intended) and PPTP
uses protocol 47 (GRE).  Thus, these do not belong in the Application Level
Gateway section.  Rather, IPsec and PPTP should be moved to the previous
section (NAT Conformance) which already mentions other protocols like TCP
and ICMP.

* There aren't specifications describing an ALG for FTP, RTSP, RTP, IPsec,
or PPTP VPN.

* What is "RTSP/RTP"?  Is this trying to say "RTSP, when it is using RTP",
or is it trying to say "RTSP and other uses of RTP".  Text needs to be
clarified.

* IPsec Passthru is pretty common on residential NATs.  However, in a CGN,
IPsec Passthru is difficult when multiple users connect to the same VPN
concentrator.  When that concentrator re-keys a session, the incoming IPsec
SPI changes and there is no simple way to determine which user should
receive that packet.  There are several workarounds to this problem,
including just ignoring it.

-d

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From: Mark Townsley <[email-masked]>
Date: Wed, 23 Feb 2011 17:29:40 +0100

I'd like to see all softwire documents be as silent as possible on specifics of NAT. The essential delta in ds-lite vs. a NAT44 CGN is that the tunnel is embedded within the NAT binding.  I think the softwire documents should explain this, then point to behave for anything else that has to do with operating a CGN. We are the tunneling folks here, the translation folks are down the corridor.

- Mark

On Feb 23, 2011, at 5:19 PM, Dan Wing wrote:

> _______________________________________________
> Softwires mailing list
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From: "Lee, Yiu" <[email-masked]>
Date: Wed, 23 Feb 2011 18:47:36 +0000

Make sense. The authors will discuss this and send the response back to
the working group. 

On 2/23/11 11:29 AM, "Mark Townsley" <[email-masked]> wrote:

>
>I'd like to see all softwire documents be as silent as possible on
>specifics of NAT. The essential delta in ds-lite vs. a NAT44 CGN is that
>the tunnel is embedded within the NAT binding.  I think the softwire
>documents should explain this, then point to behave for anything else
>that has to do with operating a CGN. We are the tunneling folks here, the
>translation folks are down the corridor.
>
>- Mark
>
>

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From: "Lee, Yiu" <[email-masked]>
Date: Fri, 25 Feb 2011 03:51:45 +0000

This is a follow-up to the WG. We agreed with Dan and Mark, we will update
the draft to reflect this change in next revision.

Thanks,
Yiu

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From: Daniel Roesen <[email-masked]>
Date: Fri, 25 Feb 2011 09:52:20 +0100

> the draft to reflect this change in next revision.

Is there any timeline for a new revision, or actually the document
becoming an RFC?

Best regards,
Daniel

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CLUE-RIPE -- Jabber: [email-masked] -- dr@IRCnet -- PGP: 0xA85C8AA0

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From: "Lee, Yiu" <[email-masked]>
Date: Sat, 26 Feb 2011 16:15:58 +0000

Hi Daniel,

We were waiting for the dhcp option to be finalized. Since it has been
resolved, our plan to release a revision next week. The draft is still
under IESG review. Thanks for the patience.

/Yiu