IPv6 explained: Understanding the Internet Protocol Version 6

Get IPv6 explained simply, with the aid of frequently asked questions answered by expert Silvia Hagen and a description of the Internet Protocol Version 6. Learn why IPv6 matters and what it means, especially for enterprise wide area network (WAN) engineers and managers.

Get IPv6 explained simply, with the aid of frequently asked questions answered by expert Silvia Hagen and a description...

of the Internet Protocol Version 6. Learn why IPv6 matters, and what it means, especially for enterprise wide area network (WAN) engineers and managers.

IPv6 explained: What is IPv6?

WhatIs.com defines IPv6 as an update to the current Internet Protocol (IPv4), which is the protocol most people use today to send data from one computer to another over the Internet. IPv6 was created to solve the depleting IP address space issue, to support stateless auto-configuration, and to provide better security and mobility.

Who created IPv6?

The Internet Engineering Task Force (IETF) defined the IPv6 standard, mainly to lengthen IP addresses from 32 bits to 128 bits. IPv6 security expert Scott Hogg uses the analogy of adding more digits to the end of a phone number so that more people can have phone numbers. In comparison, IP addresses need to be lengthened because the current address space will not be able to support the number of hosts (computers, network devices, etc.) that will need an IP address in the near future.

The IETF knew the Internet was broken more than a decade ago, which is why they updated Internet Protocol Version 4 to Internet Protocol Version 6 (IPv6) -- formerly known as IP next generation: IPng. (There was an IPv5 that never came to fruition.)

What's prompting the move to IPv6?

The new protocol is supposed to support IP addressing needs for years to come. The number of IPv6 addresses is said to be 340,282,366,920,938,463,463,374,607,431,768,211,456. (How to say the number is expressed in various ways in this WhatIs.com blog.)

IPv4 address exhaustion is the main reason why the move to IPv6 must happen. IPv6 expert Silvia Hagen says IPv4 addresses will run out around 2011 for the Internet Assigned Numbers Authority (IANA) pool and 2012 for the regional Internet registry (RIR) pools. A specific date cannot be given because it will depend on how many people request IPv4 addresses between now and address exhaustion.

Using NAT, CIDR and PAT stalled the initial threat of IP address exhaustion in the mid 1990s -- but continuing to rely on these methods today would only slightly delay the inevitable need for IPv6.

Most industry experts agree that IPv6 is the only viable way to solve IPv4 address depletion. Some organizations, such as the Pouzin Society, do not believe IPv6 is the best answer, however, and they have been working on solutions to solve the routing scalability problems that IPv6 does not address.

IPv4 compatibility with IPv6 explained

IPv6 is not backwards compatible with IPv4. Some believe this is because it was better to create a new protocol than to build on a faulty one. Others believe the lack of compatibility was a mistake that has resulted in slow IPv6 adoption.

If your network runs on IPv4, you will not be able to see an IPv6 website; likewise, if you are on IPv6, you will not be able to browse an IPv4 page. Hogg explains that if you try to access an IPv6 website on an IPv4-only network device, you will simply get a "page not found" 404 error message from your Web browser.

The only way to get IPv4 and IPv6 to talk to each other is to put in a mechanism that translates the protocols. Many wide area network devices have IPv6 features, but communication between the two protocols is not as simple as turning these device features on. There are a handful of ways to support an IPv4 to IPv6 transition. IPv6.com explains 6 to 4, dual-stack, tunneling and other methods that can be used to browse an IPv6 website. Industry expert Ivan Pepelnjack compares these network-ready routing solutions in his tip.

To get IPv6 explained further, view our IPv6 tutorial, or use our IPv6 migration guide to learn how to transition your IPv4 network to IPv6.

IPv6 explained further

This was last published in August 2010

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