11
IPv6
Since the late 1990s, it has been patently clear that the constraints of IPv4 were too great to support the ballooning demand for Internetworked services. Initially, the main focus of the limitations was on the address space with predictions of the exhaustion of IPv4 addresses ranging from early the next century (2000) through to some time over the next couple of decades. One suggested solution was that the limited address space could be overcome by using network address translation (NAT) in conjunction with private addresses as defined in RFC 1918. While NAT does provide the means for many hosts to appear as a single host (or as a small number of hosts), it introduces its own set of new constraints. Some of these new constraints are potentially more difficult to overcome or impose greater difficulties than those being solved. In particular, certain protocols do not behave at all well in the presence of NAT. However, in some cases, extensions have been added to the various protocols to try to mitigate some of those negative effects.
With this in mind, the IETF started a working group to design the next generation of the Internet Protocol in the IPng WG, which has subsequently been renamed the IPv6 Working Group. The base definition of IPv6 is RFC 2460.
For the curious among you, version 5 of the IP protocol was allocated to the Stream Protocol some time before the development of IPv6. It is a somewhat experimental protocol designed to work in conjunction with IPv4 and is based significantly upon IPv4 including using the same framing and addressing. One of its major perceived benefits was that it is a connection-oriented protocol, potentially providing improvements in the ability to provide guaranteed levels of service.
11.1 EVOLUTION AND REVOLUTION
IPv6 is both an evolutionary and revolutionary development of IPv4. As you would expect, all the base functionality that made IPv4 so successful has been reproduced, although
Designing and Developing Scalable IP Networks G. Davies
2004 Guy Davies ISBN: 0-470-86739-6