IPv6: Revitalizing the Internet Revolutionby Silvia Hagen, author of IPv6 Essentials
There are many different ideas and opinions about IPv6 around in the market. There are even people who think IPv6 will never come to life. Despite this perception, major companies around the world have been quietly developing products and services using the next generation protocol. And with the recent release of my book, IPv6 Essentials, O'Reilly has also entered the fray. Even with the enormous investment in IPv6 development, however, there are many misconceptions surrounding IPv6.
This article explains what you need to know in order to put things into perspective. It also discusses some of the myths that exist and explains IPv6's background, so that you can form your own opinion. This article is not designed to explain how IPv6 works in detail. To find out more about IPv6's inner workings, pick up a copy of IPv6 Essentials.
This article also assumes you have a good understanding of IPv4 and general networking principles.
TCP/IP version 4 (IPv4) is probably the most used protocol in our networks and in the Internet. It has proven over the years to be robust, stable, expandable, and reliable. Everyone who checks their email or surfs a Web site uses IPv4. It was developed almost 30 years ago, at a time when the current size and uses of the Internet were beyond imagination. Still, developers managed to create a lasting protocol that will be around for several years to come. About ten years ago, work began on a successor protocol. It was called IPng (next generation) at that time. The main reason for working on a new protocol was the expected IP address exhaustion. This is the reason why many people think that if they currently have enough IPv4 addresses, there is no need to think about IPv6. Additionally, we've developed technologies like Network Address Translation (NAT) and Classless Interdomain Routing (CIDR) to delay the address-space issues.
Why We Need IPv6
However, the perception that there is no need for IPv6 is a false one, for several reasons.
Reason number one: people who say there are enough IPv4 addresses are the ones who have big allocations. The government, universities, and organizations in the U.S. alone hold approximately 74 percent of the total IPv4 address space. One example: Genuity, a provider of IP network services based in the U.S., has three Class A addresses. That amounts to approximately 48 million addresses -- more than twice the address space the whole country of China has (approximately 20 million addresses). In Asia, IPv4 addresses are so rare that providers have no choice but to offer IPv6 commercial services. They are even funded by the governments to do so (Korea and Japan, for example). This is why the number of ISPs offering IPv6 on a commercial level is much higher in Asia than in Europe and the U.S. However, it is only a matter of time before European and American ISPs will need to rethink their stance on IPv6. Gartner Group, for example, estimates that the official IPv4 address space will be exhausted by 2005 or 2006.
Reason number two: NAT is an adequate short-term fix, but not a long-term solution. It doesn't allow for end-to-end security, breaks the peer-to-peer model, and creates a bottleneck in the network. For many current and future applications, especially in the area of portals and eCommerce, end-to-end security will be a requirement. And that, you will only get with IPv6.
Reason number three: In the future, it will not only be personal or network computers that will require an IP address. There are more and more devices that need a permanent IP address. The day is approaching where your mobile phone, car, PDA, TV, and even your refrigerator will have an IP address. With these changes, the need for IP address space will increase exponentially. Future services will require a higher level of security and quality of service (QOS) that, while feasible, will not be economically viable with IPv4.
The extended address space is certainly not the only reason to consider IPv6. The developers of the new protocol have learned from 25 years of experience with IPv4, and so they've optimized IPv6 for the complex networks of the future. IPv6 has many advantages, such as integrated security, an improved addressing schema, and more efficient routing and autoconfiguration that should reduce administrative costs. The features supporting mobility with IPv6 also offer possibilities for wireless networks, which IPv4 could never handle. And mobility is the future of the Internet.
Another common misconception is that IPv6 can be used only if the network backbone and the Internet backbone have been upgraded to IPv6. So why care about this new protocol today? But with the number of transition mechanisms that have already been defined and that are extended and optimized continously, upgrading is not a requirement. It is possible to create IPv6 islands at the edge of the network (or even allow an isolated IPv6 host) that utilize the IPv4 backbone to connect to other remote IPv6 islands or hosts. The IPv6 packets will travel through the IPv4 infrastructure encapsulated in an IPv4 packet (tunneling). So you can start building new segments or extending your existing segments with IPv6 and wait to upgrade your backbone in the normal course of business.
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