[LINK] IPv4 host density measured by ping

[Robin Whittle]

I couldn't find any recent research on how many computers exist on the
Net, so I did my own:

  http://www.firstpr.com.au/ip/host-density-per-prefix/

I estimate about 107 million computers acknowledging pings.  Does anyone
have insight into computers which are genuinely on the Net but either do
not acknowledge pings, or have those acknowledgements filtered out by a
router?

I also surveyed this measure of "host density" for each of the /8
prefixes 1.0.0.0/8 to 223.0.0.0/8.  There are enormous variations.

I surveyed the average host density for BGP advertised prefixes of
lengths /8 to /24.  There was considerable variation 4:1, not counting
the atrociously under-used 19 /8 prefixes.  Then I measured a bunch of
prefixes individually so I could see the distribution of host densities,
for instance in a sample of /24 prefixes.  About 1/3 of /24s did not
return a single acknowledgement when I pinged every one of each prefix's
256 addresses.

Some IPv4 space can never be used.  Some is still in reserve, and is
being handed out to RIRs at about one /8 prefix per month.  That will
probably run out around 2011 or so.  Not all the space allocated to
users (ISPs and organisations with AS numbers) is currently advertised
on the global BGP routing system.  Of the space which is advertised,
many of the advertised subnets have few if any computers connected to them.

So there is a lot of scope for making better use of already allocated
space once the supply of unallocated addresses dries up.

  - Robin