Mobile Inter-networking with IPv6 : Concepts, Principles and Practices

2

IP Version 6

640K ought to be enough for anybody.    –Bill Gates, 1981

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2.1 MOTIVATION

As the Internet began to grow at a dramatic rate during the late 1980s and early 1990s, engineers realized that the current version of the IP protocol would not be adequate to meet the demands of the Internet’s growth. Of particular concern was the availability of adequate IP addresses for all kinds of devices accessing the Internet. With 32 bits, IPv4 can theoretically provide up to 4.2 billion addresses. However, even with uniform allocation, this is insufficient given the magnitude of growth seen in wireless and mobile communication. Allocation policies in practice make this worse; a few organizations have an overabundance of addresses, whereas many others have ended up with too few. These and other considerations led to a design that could support every imaginable device that would need an IP address in the foreseeable future. With this design, one estimate is that every atom of each person on earth could be assigned seven unique addresses!

IPv6 also provides additional features. Address auto-configuration allows hosts to autoconfigure their IP addresses without the need for a centralized server. The header, which contains the essential fields for the IP protocol to work, has been simplified for more efficient processing; even with 40 bytes, the IPv6 header is more amenable to header compression ...