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The case for IPv6: Introduction, part 1

The first part of the paper provides a short overview of the advanced technical features that IPv6 offers, compared to the IP version we are using today, IPv4.


When the Internet was switched overnight to use TCP/IP instead of the formerly used NCP in 1983, IPv4 was not exactly the protocol we know today. It was, in the core. But many of the extensions and additions that we use today, have been developed much later. The basics of IPv4 were defined in RFC (Request for Comment) 791 in 1981. Path MTU Discovery was defined in RFC 1191 in 1990, Supernetting, which was designed to help ease the issue with overloaded routing tables, was defined in RFC 1338 in 1992, DHCP, which was designed to help manage the addresses in a larger IP network, was defined in RFC 1531 in 1993 and Private Addresses which we use to build our NATs (Network Address Translation) today were defined in RFC 1597 in 1994.

The reason I am mentioning this, is not to bore you with numbers of papers that you never want to read. What I would like to point out is, that when IPv4 was first introduced, it was not the mature protocol we know today. Many of the extensions to IPv4 that help us manage and maintain our IPv4 networks, were introduced later, when the need arose. Based on the need, the extensions were defined in the international working groups and defined as RFCs.

So when people argue today, that IPv6 is not mature and cannot do what IPv4 can, this is only partially true and above all, not a reason to not use IPv6. Development for IPv6 started in 1991. The core of IPv6 was standardized in 1995 and updated in RFC 2460 in 1998. Based on that standard we have many implementations around since many years. Most hardware and router vendors have implementations since the late nineties and have tested them intensely. 6to4, a main transition mechanism, that makes co-existence and transition much easier, has been standardized in 2001. DHCP Version 6 has been standardized in summer 2003. Mobile IPv6, which is going to be one of the technologies that makes you choose IPv6 over IPv4, is in the process of being standardized in early 2004. The same is true for ISATAP, another example for a transition mechanism.

IPv6 has been developed based on the rich experience we have with IPv4. IPv6 is an evolution of IPv4, it is mature in the core, it has been implemented and tested intensely up to the network layer. The developers created a protocol, which takes everything that was great about IPv4 and added flexibility to extend it, to make it the network protocol of the future. IPv6 is capable of handling the Internet growth rate and to support the new types of services, especially in the area of mobility, that we have to expect in the coming years.

There are things that we are missing in IPv6 today, that is true. But you do not need to switch today and all these additions will be defined in the coming years, just as it happened with IPv4. But you ought to become aware of how IPv6 will impact your business and your network. If you plan early, you will save money and headaches. You will be ready when it is time for you and more importantly, you will be able to determine the right moment for not extending your IPv4 infrastructure anymore, but putting your investments into the future technology.

Continue to part two: Technological advances of IPv6

For greater insight into IPv6 we recommend Silvia's latest publication, 'IPv6 Essentials' published by O'Reilly in late 2002.

Networking Silvia Hagen, owner and CEO of Sunny Connection AG is the author of a number of books. She regularly speaks at international conferences like Brainshare US and Europe, NUI Events, IPv6 Summits and other technical conferences. Sunny Connection AG ( is a leading IT consulting and education company based in Zurich Switzerland. Our main expertise is in directory services integration and in network analysis and protocols like TCP/IP and IPv6. We have more than ten years of experience in consulting middle and large sized companies, mainly in the area of industry, banking and insurance.

The IP version we are all using today, in our corporate networks and in the Internet, is IP Version 4, short IPv4. It has been developed in the early seventies by a number of pioneers who wanted to connect some educational and government networks in the United States. At the time when they started development, a network like our Internet today was beyond imagination and therefore to meet such a requirement wasn't part of their design goals. All the more fascinating it is, that they managed to create a networking protocol, which is still - 30 years later - capable of running today's Internet! But now it has reached it's age and can't be pushed any further. Time for the next generation to take over!

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