On Thu, Mar 30, 2006 at 07:08:51PM +0200, Anthony G. Atkielski wrote:
Steve Silverman writes:
The problem with allocating numbers sequentially is the impact on
routers and routing protocols.
The problem with not doing so is that a 128-bit address doesn't
provide anything even remotely close to 2^128 addresses.
But this has been known all along. It's a feature, not a bug.
If we "throw away" the last 64 bits we are left with 2**64 addresses,
which is obviously what was intended from the beginning.
Allocating to ISPs on /48 or so boundaries then maps roughly to
ipv4 /16s which are often handed out now. If a /8 in v4 space gets parceled
out by the registries in a matter of months, a /40 in v6 should last the same.
Following that logic, a /32 in v6 space should last as long as /0 in v4
space.
The current v4 /0 has lasted for some time now, it's difficult to
envision a time where we would be burning through space so fast that /32s
in v6 space wouldn't last months, if not years.
But for argument's sake, let's say a /32 lasts one day at some point in
the dim future. This gives us 2 ** 32 days before we run out. not too bad for
those of us not realistically having much of a chance to live beyond 2 ** 15 or
so.
If we "throw away" additional bits for other engineering purposes
the number of days would be 2 ** (32 - wasted bits). If we waste a full
half of those bits bits we're down to 2 ** 16 days (about 180 years).
Again, that assumes we'd burn what is equivalent to a v4 /0
every single day for 180 years. Maybe it will become a problem when everyone
has addressable nanocytes in their bloodstream. But I have a hard time seeing
how it could be described as shortsighted.
In that case, assign addresses to points in space, instead of devices.
An office occupying a given plot of land will have an IP address space
that is solely a function of the space it occupies. Routing would be
the essence of simplicity and blazingly fast.
Routing doesn't (and will never) work that way. Much like with
airlines, the cost of a path is more complex than mere distance.
IMO one problem of the Internet is that it isn't hierarchical enough.
Consider the phone system: country codes, area codes ... This makes
the job of building a switch much easier. I think we should have
divided the world into 250 countries. Each country into 250
"provinces". Yes, it would waste address space but it would make
routing much easier and more deterministic.
With a variable address length that can extend infinitely at either
end, the address space would never be exhausted. That's how
telephones work.
That would be an alternative, certainly. I'm not sure how excited
to get about a 1 byte payload needing 1000 bytes of header, but I'm sure
it's possible.
Is it worth throwing away the current post-v4 solution? Certainly
something to consider over the next 180 years.
Austin
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