[ipv6-wg at ripe.net] What is a site?

Hi,

On Mon, May 09, 2005 at 01:16:48PM +0200, Iljitsch van Beijnum wrote:
> >This is not the scenario where /128 would be used for.
> 
> Right, I got the /64 and /128 problems mixed up.
> 
> The above shows that a /64 is problematic.  :-)

Only if you assume numbered PPP links.  Which is no way mandatory 
(nor useful towards single-LAN customers).

> But how would a /128 work?
> 
> >+---------------+     +---------------------+
> >|ISP dial-up box+-ppp-+customer dial-up HOST+
> >+---------------+     +---------------------+
> 
> Stateless autoconfiguration only works on /64s because it needs a 64  
> bit interface identifier. 

So?  Please re-read what I wrote.  IPv6CP negotiates a host-ID - if the
"ISP dial-up box" makes sure that all customer host IDs connecting
to it are unique, you have unique interface identifiers.

Then send the same (!) /64 RA on all links.  Each host will assign itself
a unique IP address, and send packets for all other addresses in the
/64 towards the ISP (remember: this is a point-to-point link, there is
no other way to send it to).

The ISP router needs a bit more brains, but not very much so.

(This is conceptually not overly different from the way IPv4 DHCP works
on DSL lines in some bridged-mode deployments today - all DSL lines share 
a "virtual" bridged /24 or similar, so you don't need a /30 per DSL customer)

Gert Doering
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