Next message: Joe Greco: "Re: Assigning IPv6 /48's to CPE's?"
On Dec 31, 2007 3:26 PM, Church, Charles <> wrote:
> like a natural choice, leaving 80 bits for network addressing. This
> waste of space seems vaguely familiar to handing out Class A netblocks
> 20+ years ago. "We'll never run out"... Maybe it's just me though.
The comparison is mistaken. Not without a major fundamental change in
the way ip addresses are used (ridiculous waste of addresses by
end-sites causing them
to require numerous subnets and request additional /48s)
IPv6 provides ample room for growth at end sites, and giving out /32s
or so to ISPs
and telling them to hand out /48s and /56s seems reasonably conservative.
64-bits maximum length network address. It's not much a waste for
every end-user to get a /56
Think of it as IPv4, but instead of everyone having gotten a Class A,
every end site
got on average 0.00000006 of an IPv4 /32 (host address), no matter
how large their site.
1 IPv4 Class A is approximately 0.39% of available IPv4 space
1.67*10^7/(4.29*10^9)
1 IPv6 /48 is approximately 0.00000000000000000000827% of available
IPv6 space.
You need a calculator for that second one :)
But assignable space in V6 could be exhausted without end-site IPs running out.
The place where major problems could be run into is deciding how big a
block your ISPs and
LIRs get, or if the registries are entertaining the concept of PI
space for v6.. how large
those blocks are. Does a small ISP ever get such a small block that
they may run out of /48s
to assign?
Does a large ISP ever get such a large block, the RIRs may run out of
ISP blocks to assign?
Both situations would be extremely undesirable.
In the former case, they need multiple blocks, but RIR policy for v6
might not provide a way
for them to get that.... the utilization of additional allocations
also add undesirable complexity
to networks, which is very bad: design of IPv6 is supposed to avoid
such things.
In the latter case... IPv6 IP addresses have not been 'exhausted',
but now, there can now
be no new ISPs or PI allocations; everything having been assigned to
some major provider
who has not given out very many of their /48s yet,
or who is giving out /56s and hording the rest of the address space,
never to be assigned.....
--
-J
