Addressing plan exercise for our IPv6 course

Fri Jul 23 15:53:33 UTC 2010

> It is not about how many devices, it is about how many subnets, because you
> may want to keep them isolated, for many reasons.
> 
> It is not just about devices consuming lots of bandwidth, it is also about
> many small sensors, actuators and so.

I have no problems with giving the customer several subnets. /56 is
just fine for that. I haven't seen any kind of realistic scenarios
which require /48 for residential users *and* will actually use lots
and lots of subnets - without requiring a similar amount of manual
configuration on the part of the customer.

So we end up with /56 for residential users.

> And I'm not saying to forget about what we have learn with DHCP, in
> fact DHCPv6 has many new and good features, but for many reasons,
> autonconfiguration is good enough, and much more simple.

For our scenarios DHCPv6 is needed, autoconfiguration is *not* good
enough. It seems quite likely that in many cases the CPE will use the
/56 it gets from us (via DHCPv6 PD) as basis for autoconfiguration on
the LAN side - and that's just fine and dandy.

[I see no point in repeating the arguments for why autoconfiguration
is not good enough - this has been beaten to death, repeatedly, on
lots of IPv6 lists.]

Steinar Haug, Nethelp consulting, sthaug at nethelp.no