IPv4 has only about 4.3 billion addresses available—in theory, and we know that we don’t even get to use all of those. There really are only about 250 million addresses that can be assigned to devices.

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Why using Ipv6?
IPv4 has only about 4.3 billion addresses
available—in theory, and we know that
we don’t even get to use all of those.
There really are only about 250 million
addresses that can be assigned to devices.
There are a lot of reports that give us all
kinds of numbers, but all you really need
to think about to convince yourself that
I’m not just being an alarmist is the fact
that there are about 6.5 billion people in
the world today, and it’s estimated that
just over 10 percent of that population is
connected to the Internet, which means will run out of them, and it’s going to happen within a
few years.
That statistic is basically screaming at us the ugly truth that based on IPv4’s capacity, every
person can’t even have a computer—let alone all the other devices we use with them. I have
more than one computer, and it’s pretty likely you do too. And I’m not even including in the
mix phones, laptops, game consoles, fax machines, routers, switches, and a mother lode of
other devices we use every day! So I think I’ve made it pretty clear that we’ve got to do
something before we run out of addresses and lose the ability to connect with each other as we
know it. And that “something” just happens to be implementing IPv6.
The problem of IPv4 address exhaustion was recognized in the early 1990s, when various
experts made projections showing that if the increasing rate of the allotment of IPv4 addresses
continued, the entire address space could be depleted in just a few short years. A newversion
of IPknown in the development stage as IP Next Generation or IPng, and which is now
IPv6was the proposed solution. But it was
recognized that developing the new standards would take time, and that a short-term solution
to IPv4 address depletion also was needed.
That short-term solution was Network Address Translation (NAT), which allows multiple
hosts to share one or a few public IP addresses. Behind the NAT device, private IP addresses
are used.
NAT has been so successful in slowing IPv4 address depletion, and has become such a
standard part of most networks, that to this day many still question the need for a new version
of IP. But the widespread use of NAT has changed the open, transparent, peer-to-peer Internet
into something much more like a huge collection of client-server networks. Users are seen as
being connected around the "edge" of the Internet, and services flow out to them.
Although most of the IPv6 standards were completed years ago, it is only recently that serious
interest in migrating from IPv4 to IPv6 has been shown. There are two fundamental drivers
behind the growing recognition of the need for IPv6.
The first is widespread vision of new applications using core concepts such as mobile IP,
service quality guarantees, end-to-end security, grid computing, and peer-to-peer networking.
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2. NAT stifles innovation in these areas, and the only way to get NAT out of the way is to make
public IP addresses abundant and readily available.
The second fundamental driver for IPv6 is the rapid modernization of heavily populated
countries such as India and China. A compelling statistic is that the number of remaining
unallocated IPv4 addresses is almost the same as the population of China: about 1.3 billion.
With its aggressive expansion of its Internet infrastructure, China alone in the near future will
represent an unsupportable pressure on an already strained IPv4 address pool. In India, with a
population size close to China's, 4- and 5-layer NAT hierarchies exist just to support the
present demands for IP addresses.
IPv6 replaces the 32-bit IPv4 address with a 128-bit address, making 340 trillion trillion
trillion IP addresses available. That number will meet the demands for public IP addresses,
and answer the needs of the two fundamental drivers discussed here, well into the foreseeable
future.
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