IP Version 6
As was pointed out earlier, the explosive growth of the Internet has pushed it to the very limits of the original design. The number of IP addresses has grown almost exponentially in recent years, leading to the fear that there will soon not be enough addresses to connect all the devices and computers that people want to connect. This fear has been assuaged for large corporations, which have been placing their networks almost entirely behind firewalls and proxy servers and using their own internal networks, where each corporation is free to use its own class A network address. However, there will come a time in the near future when IP version 4 will impede the growth and management of the Internet, requiring a solution.
To find a solution to the limitations of the 32-bit address space and the limits to the routing protocols in the current structure of TCP/IP, the IETF and others began working on a new version of IP several years ago. Different working groups originally proposed different solutions, but over time these groups have arrived at a consensus on the next generation of IP, known as IPng or more correctly as IP version 6 (often shortened to IPv6). It was formally accepted by the IETF in December 1994, and the current specification is in RFC 2460. IPv6 defines a 128bit IP address space compatible with the current implementation of TCP/IP (version 4, or IPv4). The specifications call for packets to include additional information for improved routing and handling of mobile devices. IPv6 will not only enlarge the address space available, but will also improve network performance, ease configuration issues, and provide enhanced security.
REAL WORLD Unreal Numbers of Addresses
IPv6 addresses have four times the number of bits that IPv4 addresses do (128 vs. 32), but what does that actually mean? The 32-bit address structure can enumerate more than 4 billion hosts on as many as 16.7 million networks, but the number of potential IPv6 addresses totals 4 billion times 296 the size of the IPv4 address space. This works out to 340,282,366,920,938,463,463,374,607,431,768,211,456 possible addresses. Of course, given routing and hierarchical requirements, this theoretical address space is diminished greatly when making practical estimates. The mathematically minded should consult RFC 1715, in which Christian Huitema analyzes other addressing schemes (including the French and U.S. telephone systems) and concludes that 128-bit addressing will suffice for another 25 years of Internet growth.
Despite the benefits, many are not looking forward to the deployment of IPv6. After all, most companies try to minimize the number of protocols they need to support. Supporting yet another protocol is regarded with less enthusiasm than Friday afternoon performance audits. The transition will be gradual, however, and there is an incredible amount of work in progress to ensure that it is painless as well.
IPv4 and IPv6 will exist side by side for an extended period, and most vendors are working to see that future products support both versions of IP seamlessly. For example, Microsoft is currently developing an IPv6 stack for Windows 2000 that will operate side by side with the IPv4 stack currently in use, which means that existing functionality won't be altered, and all applications written for the Winsock 2 (Windows Sockets) interface will automatically be IPv6 compatible once an IPv6 stack is installed.
NOTE
Windows 2000 does not ship with an IPv6 stack. While some operating systems, such as Linux kernels version 2.2 and later do ship with IPv6 support, IPv6 is still in the experimental stage, and supporting it is something you needn't worry about right away. However, if you want to be prepared, you can start by reading IPv6 Clearly Explained by Pete Loshin (Morgan Kaufman Publishers).
EAN: 2147483647
Pages: 366