Mark Andrews writes:
Which was why IPv6 when to 128 bits rather than 64 bits.
That won't help. It will add perhaps 25% to the lifetime of the
address space, no more.
64 bits of address space would have been fine to give
everyone all the addresses they would need. 128 bits gives
them all the networks they will need.
No, it does not. It's only twice as much as 64 bits, and 64 bits is
only twice as much as 32. Addressing schemes consistently allocate
addresses in a terribly shortsighted way as bit spans, rather than
address ranges, so address ranges are consumed much more quickly than
they should be.
This seems to be one of the most consistent mistakes of computer
engineers ever since computers were invented. After all these
decades, they still have no clue.
Well for home users one really only needs to be able to
request /64's as needed. There is no need for home users
to have contiguious /64's. It means the ISP has some extra
routes in there IRP. If they really need contiguious /64's
then have them renumber to get the contigious block, even
then the block size doesn't need to be a power of 2.
A /62 and an adjacent /63 will work.
Allocating is powers of 2 is a trade off.
I suspect the same will apply to cell phones etc.
Renumbering is also much easier, though not perfect. Time
spent on improving renumbering support will also aid more
efficient utilisation. We have the concept of deprecated
addresses in IPv6 which is a powerful tool if used correctly.
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: Mark_Andrews(_at_)isc(_dot_)org
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