-----Original Message-----
From: ietf-bounces(_at_)ietf(_dot_)org
[mailto:ietf-bounces(_at_)ietf(_dot_)org] On
Behalf Of Bernard Aboba
Sent: Friday, February 15, 2008 6:21 AM
To: ietf(_at_)ietf(_dot_)org
Subject: Re: I-D Action:
draft-rosenberg-internet-wait-hourglass-00.txt
Lars Eggert said:
"A big driver for SCTP was for use a signaling protocol.
Other SDOs are
using SCTP for signaling in their network architectures, and
are also
now introducing NAT functionality at controlled places in these
architectures. This is why I believe and have argued that an
IETF BCP
that documents how to correctly NAT SCTP is the right thing to
produce. (And, FWIW, DCCP. There's some interest in that as
well, but
not such an immediate one as for SCTP.) As a SIP-area person, this
mode of operation should be familiar to you.
Will this BCP make SCTP available behind a home NAT? Nope. But it
provides a specification that people can refer to who design network
architectures that are more tightly controlled than the end user
Internet, i.e., where people can define and then require
their NATs to
have this functionality."
I agree with Lars here -- having a specification is the first step.
There is a milestone in BEHAVE for a SCTP NAT, along the lines of
BEHAVE's milestones (some completed) for TCP, UDP, and ICMP. We also
have a milestone for a DCCP NAT.
However, I would suspect that clearly specifying how SCTP and DCCP
work with NAT would eventually make it possible to obtain a home NAT
supporting those protocols, particularly if implementations were made
available within the popular distributions (e.g. DD-WRT) on
which those home NATs are frequently based.
I am not aware of the status of SCTP NAT code, but I did learn
this week that there is a Linux implementation of DCCP NAT.
On another note, I think it makes a difference whether
UDP/TCP is combined
with IP at the waist, or whether UDP/TCP is considered a
lower layer on
which IP, etc. can run. That is, whether we have general NAT
traversal
mechanisms which support a wide array of applications, or
whether we end
up having to modify each individual protocol. The draft
seems to suggest
the latter approach. I disagree.
A simple UDP tunneling protocol sounds useful, too.
There are currently two drafts for running SCTP and DCCP over
UDP. I look forward to discussing the benefits of a
per-protocol UDP tunneling approach versus a generic, simple
UDP tunnel approach.
-d
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