[sclug] Who needs a /48?

[Ed Davies]

On Wed, Apr 10 2013 14:27:56 +0000, Ed Davies wrote:
>> By the time you've dropped a few bits off the front for different
>> addressing schemes that only leave a few hundred addresses for each
>> of the 10 billion or so people likely at peak peeps - a small enough
>> number that some sort of careful management would be required.

On 2013-04-14 11:39, Paul Lettington replied:
> I have to question the maths here. How many bits are you dropping off
> the front, and what for?

You're right - I did drop off a few too many bits.

It's been a while since I've looked at IPv6 closely: I have, I think
(most of my books have been in storage for a while) the first edition
of this book

http://www.amazon.com/IPv6-The-Internet-Protocol-Edition/dp/0138505055

published in 1995. I got bored waiting for IPv6 shortly afterwards.

As I recall the top three bits were allocated to different schemes
though I know the details have changed since then but I think it's still
three bits. My slip was to think 3 bits, 8 combinations then drop off
a whole byte.

However?

> It's worth noting that IPv6 allocations are currently only happening
> from 2000::/3 which is 1/8th of the possible address space. If the world
> chews through that significantly faster than expected, the plan is to
> re-think the address allocation policy before moving on to the next
> 1/8th.

So I was right to drop some bits. What I fail to understand, though, is
why the current scheme is even considering the possibility of a re-think
when smaller, but still vast, allocations would make the need for one all
but impossible

Ed.