Please post to this blog any materials, resources, or comments you would like to discuss for organizations

transitioning to IPv6.

Excerpt from Chapter 8:

IP VERSION 6 (IPv6)

Outgrowing IPv4

Although IPv4 continues to dominate the Internet’s traffic, it has passed its prime.  Most seriously, the 32-bit IPv4 address space has proven to be too small. In

theory, the 32-bit IPv4 address space permits over four billion IP addresses. Unfortunately, these addresses were given out inefficiently. First, the United States,

which originated the architecture, assigned about a third of all IPv4 addresses to itself. Second, and more seriously, IP addresses were only given out in chunks of

approximately 256 addresses, 65,536, or 16.8 million addresses.

If a firm needed 300 IP addresses, it was bumped up to the next step, 65,536 addresses. In such firms, nearly all of the IP addresses went unused.  Although the

Internet Assigned Number Authority (IANA) fairly quickly switched to the classless inter-domain routing (CIDR) system, which gave number assignments in smaller

increments, assignments were almost always generous to allow room for growth. Overall, only about 14 percent of all IPv4 numbers are actively used.

This limited supply of IPv4 addresses, the rapid Internet growth of economies in Asia, and the explosive growth of mobile devices needing their own IP addresses

werea recipe for disaster. In 2011, the disaster occurred. The IANA gave out the last of its IP addresses to regional registrars. The registrars soon ran out of this

last allocation, apart from a few addresses kept in reserve for special purposes.

IPv6

The Internet Engineering Task Force had long foreseen this crisis. In its 1994 meeting, it decided to create a new IP version. The IETF gave this new version the

designation IP Version 6 (IPv6) when the first RFCs (Requests for Comments) were released in 1995. Over the next few years, the IPv6 standards family continued

to grow and mature. It was soon ready to be used, and many networking and computer vendors began to build IPv6 into their products.

The most fundamental change in IPv6 is the move from 32-bit addresses to 128-bit addresses. This does not produce merely four times as many addresses. Each

additional bit doubles the number of addresses. So while there are just under 4.3 billion (4.3 × 10^9) IPv4 addresses, there are 3.4 × 10^38IPv6 addresses—34

undecillion. To see what this means, there are about seven billion people in the world today. For each person, there are 5 × 10^28IPv6 addresses.

Organizations soon found that using these new equipment capabilities, however, was a great deal more work than simply turning them on. For many years, few

organizations saw the need to make the expensive upgrade to IPv6 because they had enough addresses. In addition, Network Address Translation (NAT) greatly

extended the use of existing IP addresses in the firm, at the cost of some complexity, but at the gain of some security. IPv6 would have the mandatory inclusion of

IPsec security functionality, but IPsec was quickly modified to work with IPv4 as well. Seeing no hard business case for upgrading, few companies did. Now,

however, nearly all companies are beginning to at least plan for the implementation of IPv6, and many have already done so. As we will see in Chapter 9, companies

have found that IPv6 implementation is a long and complex process. They need employees who understand this new protocol and other “v6” protocols such as

ICMPv6 and DHCPv6.