Re: ND-proxy applicability and loop-prevention

[Pekka Savola <pekkas at netcore.fi>]

On Mon, 29 Mar 2004, Erik Nordmark wrote:
> > >  - it is too hard for them to explicitly delegate prefixes
> > 
> > Note that this is not a binary decision, i.e., the ISP might decide
> > that "OK, it's not too hard for us to delegate the prefixes, but if we
> > do that, we want some extra payment from the user for the trouble".  
> 
> So then you end up with a single IPv6 address, right?

Not necessarily.  If you don't run something like PPPv6 on the link to 
the customer, just advertising a /64 on the customer link seems to be 
the simplest thing the ISP can do.  (Even simpler than just a single 
IPv6 address.)

Without ND-proxy or bridging, that's one IPv6 address.

> > In that kind of environment, ensuring that the users have tools to
> > cope with a /64 prefix as well would seem to be really important.
> 
> But the /64 isn't delegated to the subscriber - it is merely assigned
> to the link between ISP and the subscriber.

Sure, but with ND-proxy this distinction is irrelevant, which was the 
the point to begin with.
 
> I think RFC 3177 is quite clear on its recommendation.
> Why can't we simplify the message and avoid developping additional protocols
> (which are as likely to slow down IPv6 deployment as speeding it up) by saying
> that ISPs which don't delegate at least a /64 (using a protocol/mechanism
> which delegates it to the *subscriber* and not just assigning it to the link
> from the ISP and the subscriber) doesn't follow the implications of the
> recommendation in 3177?

The problem is that with the same trouble it takes to fully delegate a
/64, the ISP could do a /48 as well.  That is a good thing also, of
course.  My worry is that the ISPs end up doing nothing unless they
have simple enough means available.

I mean, the message could also be "just give every customer a
delegated /48.  If that is not possible, advertising a /64 on the link
is better than nothing."

This takes no stance on the other "subnet extending" scenarios where
ND-proxy could be desirable, like a gadget on firewire connected to
your PC.

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings


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