On 9 July 2015 at 11:42, Matthew Huff <mhuff@ox.com> wrote:
What am I missing? Is it just the splitting on the sextet boundary that is an issue, or do people think people really need 64k subnets per household?
One thing you're missing is that some of these new-fangled uses for IP networking will want to do their own subnetting. It's not "here's a subnet for the car", it's "here's a /56 for the car to break into smaller pieces as required". A /56 isn't 256 subnets, it's 8 levels of subnetting (or 2 levels, if you're human and want to subnet at nibble boundaries). A /48 is 16 (or 4) levels. I have four vehicles, so I'd want to carve out a /52 for "the car network" to make the routing and security easier to manage, and leave room for expansion (or for my guests...) One more consideration for you: we're currently allocating all IPv6 addresses out of 2000::/3. That's 1/8th of the space available. If we discover we've messed up with this sparse address allocation idea, we have 7/8ths of the remaining space left to do something different. -- Harald