The Internet Protocol (IP) is a key part of the mechanism for transferring data across the internet. Information is broken into small packets, and the IP is responsible for relaying and routing them around the system by identifying and locating hosts. The current version is IPv4, and because it is made up in sets of 32 bits, it is limited to having just under 4.3 billion addresses. It seems like a lot but they are almost all used up.
For every day users, access to the internet will carry on just as before, but finding new addresses in the IPv4 system – even allowing for such things as the reallocation of redundant or dormant addresses – is going to be difficult. In effect, we have reached a cap on the growth of the internet.
In February 2011 IANA (Internet Assigned Numbers Authority) handed out the last IP address blocks from the global IPv4 central address pool. In a short while, these will be used up. The current best guesstimate is that the last batches will be assigned somewhere around June or July 2011.
This problem didn’t appear out of the blue. Although the original designers must have thought that four billion addresses plus must have been more than adequate, it was apparent as long as fifteen years ago that something must be done to prevent the internet from running out of addresses.
IPv6 was the outcome of that thinking. It has a number of rather important advantages over IPv4:
- It uses 128 bits instead of 32 bits. This allows for 340 undecillion (3.4 with 38 zeroes after it) addresses. That is a lot but then again that is what they said last time.
- It comes with the ability to multicast. Information can be sent to different targets in one operation.
- It allows for a greater variety of devices to be connected to the internet.
- It allows for mobility of machines. This will make it easier for secure business communications for staff traveling with laptops for instance.
An IPv6-based internet is designed to allow growth for generations to come, and is the only long-term solution to the present lack of address space on the internet. The problem therefore becomes how to implement it.
World IPv6 day, scheduled for 8 June 2011, is a global-scale “test flight” of IPv6 sponsored by the Internet Society — a nonprofit organisation “dedicated to ensuring the open development, evolution and use of the Internet for the benefit of people throughout the world.”
Google, Yahoo and Facebook will be participating with other major organisations, and will be offering their content over IPv6 for a 24 hour period. This is a motivational effort to ensure that providers of internet services and the associated software and hardware are in good shape to handle the switchover from IPv4 to IPv6.
Most regular users of the internet should not be affected at all. Web services, internet service providers, and operating system manufacturers will be updating their systems to ensure internet users enjoy uninterrupted service.
From the provider’s point of view, there are a number of methods available to them to handle the handover.
- Services can be run side by side for a while using what is called a dual-stack approach.
- In certain circumstances some isolated IPv6 networks will be able to run over an IPv4 network by adding a prefix which will allow passage of data.
However, these are temporary measures designed to smooth out the process of the inevitable transition to IPv6.