As a side note, in 2014 just 4% of internet traffic hitting Google used an IPv6 address. The other 96% were still using old IPv4 addresses, so I am not too worried whether an OBI can do IPv6 yet.
As the number of available IP addresses dwindled and the "there will soon be no more IP addresses" scare went out, some companies gave up chunks of their IP addresses. While this may not seem like a lot of addresses, you need to understand how IP addresses were first allocated.
The first octet (the first digit A of A.B.C.D) was originally assigned to large companies. No one at the time thought much about this except that large companies had a need.
So GE got 3.x.x.x and BBN got 8.x.x.x and IBM got 9.x.x.x and HP got 15.x.x.x, DEC got 16.x.x.x and Apple got 17.x.x.x, etc.
This first number ranged from 0 to 255 and had assignments to one or multiple uses.
http://en.wikipedia.org/wiki/List_of_assigned_/8_IPv4_address_blocksSo up until a decade or two ago, if you saw an IP address of 15.1.2.3 or 15.17.122.7, if it started with 15, it was HP, 19 and it was Ford Motor Company. It didn't take long to allocate all those 156 blocks of numbers. Then as the Internet caught on, some of those blocks were further divided.
That meant at the outset, HP had 16,777,216 addresses, IBM had 16,777,216 addresses, BBN had 16,777,216 addresses and so on, whether they actually needed them or not.
Over time some of these companies rearranged what IP addresses they were using and gave up blocks of addresses. Not all of their PC's, computers, routers, workstations or mainframes needed to be accessed directly from outside their firewall.
As new technology took off, devices started using more and more IP addresses, Cellphones, computers and the like all wanted one. The powers that be decreed that if they came up with a new numbering scheme, each person on earth could have *a TON* (a technical term) od addresses assigned to them.
One writer did some calculations to prove that some of the initial numbers of IPv6 addresses would not be implemented. Still the numbers are staggering.
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http://rednectar.net/2012/05/24/just-how-many-ipv6-addresses-are-there-really/There are only 4.2×10^37 42 undecillion IPv6 addresses currently defined and usable.
With a bit of creative programming, it would only take 69000 years to scan all the IPv6 addresses on a 48 bit IPv6 subnet if you were scanning at a million addresses per second.
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As CNN reported in 2012:
The Internet's address book grew from "just" 4.3 billion unique addresses to 340 undecillion (that's 340 trillion trillion trillion). That's a growth factor of 79 octillion (billion billion billion).
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I wonder how many years it will take before we start running out of those addresses?
