North American Network Operators Group
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Re: IANA reserved Address Space

  • From: Gerald
  • Date: Sat May 31 00:56:16 2003 
On Fri, 30 May 2003, Joel Jaeggli wrote:

> As a related question I guess I'd ask what sort of simulation requires
> more than 16.7 million discreet ipv4 adresses (1/256 of the whole) in
> order too simulate a reasonable subset of the whole ipv4 internet.

I don't have an answer for that one. :-) I came across the numbering for
this in another lookup I was doing and it seemed relevant:

10.0.0.0/8     16,777,214 unique hosts maximum
192.168.0.0/16 65,534 unique hosts maximum
172.16.0.0/12  1,048,574 unique hosts maximum
 Total: 17,891,322 unique addresses (before further subnetting)

What "real world" scenario would use more than almost 17.9 million hosts?

That doesn't count NAT'ing within private addressing if the project is
large enough and primarily using outbound traffic.

RFC1884 sets aside fec0::/10 for IPV6 Private addressing. That's enough to
fit all of IPV4 addressing inside of the private addressing alone. (Anyone
have a total number of unique hosts on that one?)

Gerald