Addressing plan exercise for our IPv6 course

Sat Jul 24 05:50:46 UTC 2010

On Fri, 23 Jul 2010 13:26:43 -0700
Matthew Kaufman <matthew at matthew.at> wrote:

> sthaug at nethelp.no wrote:
> >> 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.
> /56? How about /62? That certainly covers "several"... and if you're 
> really worried they might have too many subnets for that to work, how 
> about /60?
> >  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.
> >   
> Only because people think that the boundaries need to happen at 
> easy-to-type points given the textual representation. /56 is still 
> overkill for a house. And there's several billion houses in the world to 
> hook up.
> 

So you're also strongly against 48 bit Ethernet MAC addresses? Dropping
the two bits for group and local addresses, that's 70 368 744 177 664
nodes per LAN. How ridiculous! What were those idiots+ thinking!

"48-bit Absolute Internet and Ethernet Host Numbers", by Yogan K. Dalal,
Robert S. Printis, *July 1981*

http://ethernethistory.typepad.com/papers/HostNumbers.pdf

+ not actually idiots