Re: DSTM Considered Harmful [Re: (ngtrans) final ngtransagendaforIETF-53 in Minneapolis]

From: Myung-Ki Shin (mkshin_at_no.spam)
Date: Tue Mar 19 2002 - 18:18:10 PST


Christian Huitema wrote:

> The BIA would rewrite "connect AF_INET 1.2.3.4" to "connect AF_INET6
> x:x:x::1.2.3.4", where x:x:x::/n is either the IPv4 mapped address
> prefix (configuration less environment) or a prefix managed by a
> specific NAT-PT (explicit configuration). The packets would be routed to
> the NAT-PT, which would then do its stuff.
>
> > >We may try to provide access to legacy
> > >applications using a dual-stack mechanism,
> >
> > then you need an IPv4 address per host and manage IPv4 routing.
>
> ....
>
> By the way, the "port range" option is probably not compatible with any
> attempt to perform local communication. Think of two 4over6 nodes that
> would happen to get the same address and different ports, and then try
> to communicate. The results will be interesting. So, deciding whether
> "local communication between legacy IPv4 applications" belongs to the
> scenario or not is really an important issue.
>
> -- Christian Huitema

  First, I'd like to classify the problem space on transition.

   1- An IPv6 node in an IPv6 network (no IPv4 routing) wants to talk to
       an IPv4 node in legacy IPv4 Internet, (and vice versa).
   2- A legacy IPv4 application on IPv6 node (dual stack) wants to
       talk to other IPv6 destinations (and vice versa).

   Problem 1 is about connectivity (tunneling or translation), the
solutions
   would be NAT-PT, DSTM, etc.
   Problem 2 is about application transition - the solution would be
   BIA.

   Now, there will be a situation on combination of problem 1 & 2.
   (that is, when an IPv6 node wants to talk to another IPv6 destination
   (with IPv6 native or tranlslated/mapped address) and there is no
application
   to do so ....).
   So, we (network/node administrators) will need NAT-PT+BIA or DSTM+BIA,
etc.

   I think the "local communication between legacy IPv4 applications
   under DSTM-port option" problem is inherent from problem 2.
   So, we can avoid the possibility by using BIA.
   For local comunication, IPv6 will be used.
   If we achieve this, DNS query results might be very important.

   Myung-Ki.



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