David Conrad wrote:
And what are these benefits to the network user? Cheaper numbers
from a supply that's already astronomically large?
The RIRs, based on IETF guidelines of minimum prefix size and HD
ratio, are allocating /21s, /20s, /19s, and shorter to individual
ISPs. How many of these prefixes are there in IPv6 as compared to IPv4?
Assuming your question wasn't rhetorical...
The /N is numbered from the left.
IPv6 unicast space is 2000::/3, which is the same size as
192.0.0.0-223.255.255.255 in IPv4, i.e. the old class "C" range.
In both places, /21 has the same meaning.
There is lots of space to assign such prefixes.
That *isn't* the problem.
The problem is, how efficiently the space is allocated, in terms of
*number* of allocations, regardless of size, especially viewed over a
window of time rather than a single snap-shot.
If growth by ISPs results in new allocations, the number of routing
slots in the DFZ grows. DFZ slots are a critical resource.
DFZ slots are in extremely short supply, both because of the success of
IPv4, and because of poor allocation policies throughout the life of
IPv4. (Not all of those are the result of poor planning or
implementation, but enough of them are.)
If it weren't the case that DFZ slots were *already* in short supply,
there wouldn't be as much of a concern as is the current case.
And to answer OP's question:
The benefit to the network user is, a continued operation of the
Internet, as you know it.
Running out of DFZ slots will cause severe hardship for everyone, and
has the added risk of placing a financial squeeze on many ISPs at the
Tier1/Tier2 level.
A further market shake-out would likely benefit only the survivors of
the shake-out, and certainly not their customers, i.e. you and me.
Brian
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