Help with DHCPv6 client-identifiers

[sthaug at nethelp.no]

> > Let's turn it around - can you give examples of routers that can
> > *not* route on the full 128 bits?
> 
> It does not matter, because it is proscribed. Using more than
> /64 for routing is like assuming specific values for reserved
> fields.

And I claim that ship sailed long ago. However, I assume we won't
agree here. I'll continue to use more than /64 for routing where
I find it convenient, and I'll continue to insist that equipment
we buy can route on all 128 bits.

> It works until it breaks, and even worse, just like assuming
> specific values in reserved fields, if it becomes widely used
> enough in practice, that becomes a "de-facto" change to the
> standards and will restrict the future flexibility of protocol
> evolution.

And I claim that change has already happened.

> For example, so far most IPv6 stuff is marketed as high-end
> added-cost option, but I can easily imagine some time soon some
> engineer in Taiwan or Guangdong or Bangalore will be designing
> in a hurry to a low price target an IPv6 routing chipset with
> 64-bit only routing tables. It would be very disappointing if
> this were discouraged by the "de-facto" global usage of network
> prefixes longer than 64 bits.

If I were a router manufacturer I would encourage my competitors
to create routers that could only route on the first 64 bits.

Steinar Haug, Nethelp consulting, sthaug at nethelp.no