RE: [AVT] Re: RTP/RTCP Port Sharing -> SCTP

Henning,

The NGTRANS group is working on the issue of IPv6 behind NAT. I recently
submitted a draft (draft-huitema-shipworm-00.txt) that proposes a
solution for getting IPv6 addresses from behind a NAT. This is a rough
first draft, that will be discussed in the NGTRANS group, and that will
certainly have to be perfected. However, it provides a credible solution
for making IPv6 available everywhere.

-- Christian Huitema

> -----Original Message-----
> From: Henning G. Schulzrinne [mailto:hgs@cs.columbia.edu]
> Sent: Saturday, July 21, 2001 9:53 AM
> To: Michael Thomas
> Cc: Jonathan Rosenberg; Fairlie-Cuninghame, Robert; 'Leonid
> Rosenboim'; Ross Finlayson; avt@ietf.org
> Subject: Re: [AVT] Re: RTP/RTCP Port Sharing -> SCTP
> 
> Michael Thomas wrote:
> >
> > Jonathan Rosenberg writes:
> >  > Then you read draft-rosenberg-sip-entfw-02.txt, due out this
> week, which
> >  > explains how to handle this case.... :) The mechanism in there
> uses
> >  > bidirectional streams (which we call symmetric) whenever only one
> side its
> >  > natted, and otherwise uses a network intermediary outside of the
> firewall
> >  > when both are behind nats that don't support Christian's
> >  > http://search.ietf.org/internet-drafts/draft-huitema-natreq4udp-
> 00.txt. When
> >  > contacting this network intermediary, its still useful to use
> symmetric RTP.
> >
> >    Sigh. If the end result of most media sessions is a rendezvous
> >    to a intermediary, then our bragging rights over the IN will
> >    be nullified. I know that this is the implication of NAT's, but
> >    it still depresses me.
> 
> It would be nice if all the effort expended on fixing the NAT stuff
> would be matched by people deploying IPv6 applications (enabling IPv6
> on
> recent Solaris and Linux boxes, as well as routers, seems pretty
> trivial, from our experience) or dispelling the notion that you can't
> get addresses, which seems to often be perpetuated by people who have
> other agendas (such as making it difficult to use more than one
> computer
> on a home DSL/cable modem).
> 
> That said, I wonder if it wouldn't be easier to just have the client
> set
> up one secure tunnel to this outside entity with a real IP address,
> for
> all applications that are stymied by NATs, rather than inventing a new
> mechanism for each application. This does mean two relaying points,
> but
> avoids all the negotiation and myriad special cases. Can this be done
> with the typical VPN setups in some of the more recent OSs?
> 
> --
> Henning Schulzrinne   http://www.cs.columbia.edu/~hgs
> 
> _______________________________________________
> Audio/Video Transport Working Group
> avt@ietf.org
> http://www.ietf.org/mailman/listinfo/avt

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