Subject: RE: draft-ipngwg-default-addr-select-00.txt

From: Richard Draves <[email-masked]>
Date: Mon, 25 Oct 1999 23:51:57 -0700

> 	Now one can easily say that the tunnel interface should 
> have been
> assigned the globally routable address in the first place.  
> Because of the
> way our implementation currently handles tunneling that 
> wasn't an option.
> It may be that the answer is to simply make tunnel interfaces 
> "first-class"
> interfaces and this scenario will go away.  I suspect that 
> with 6[to|over]4
> that is going to be essential anyway.

So you can't assign global addresses to your tunnel interfaces?
Ignoring the "fix your implementation" response...

One thought is that an interface that can't be assigned addresses shouldn't
qualify as an interface. So from this perspective, your node would just have
the ethernet interface plus a routing table entry referring to an
implementation structure that has some passing similarity to an interface.
Then the global address would be available as a source address when sending
to the 6bone.

Another thought: how will your node receive packets from the 6bone that are
sent to the global address? They will be arriving via the tunnel. So it
would seem that your implementation uses a "weak host" model? In Oslo and
Tokyo the working group was considering a "semi-strong" model for IPv6 that
I think would rule out your implementation (at least if the tunnel is
considered to be an interface).

A final thought, appropriate only for routers: you could consider the
ethernet interface to be originating/receiving packets using the global
address, and it's internally forwarding the packets over to the tunnel
interface. If this is a desired viewpoint, I'd want to change the draft to
be more explicit about effectively enlarging the candidate set of source
addresses on routers.

Rich
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