IP4 Space

Owen DeLong owen at delong.com
Fri Mar 5 01:55:26 UTC 2010


Folks, I know that IPv4 is down to bread crumbs.

That's why I'm ready for IPv6 and hopefully the rest of you are or will be soon.

However, let's consider how much address space is saved by going from /30 to /31
on every point-to-point link in the internet...

Let's assume that there are ~1 million routers on the internet with an average of 8
point to point interfaces. (I think there are probably more like 1/4 million and the
average is probably more like 2, but, absent real numbers, I'll be uber-conservative).

8 million /30s is 32 million IPs, or, 2 /8s world-wide.
8 million /31s is 16 million IPs, or, 1 /8 world-wide.

We burn roughly 14 /8s per year in new allocations and assignments.

So, assuming:
	1.	There are actually 8 million point to point links in the internet
	2.	All of them are currently /30s
	3.	Absolutely optimum use of addresses for all those links
	4.	All of them are converted to /31s

(none of these assumptions is likely in fact)

The most we could achieve would be to extend IPv4 freepool lifespan
by roughly 26 days. Given the amount of effort sqeezing useful
addresses out of such a conversion would require, I proffer that
such effort is better spent moving towards IPv6 dual stack on your
networks.

Owen





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