From the Actrix Online Informer June 2012

IPv4 and IPv6

by Rob Zorn

One switched-on reader has asked us a couple of questions about IPv4 and IPv6.

So first a little context (jargon alert many readers will want to skip this)

Every device, such as a computer, ipad or mobile phone, that connects to the internet has a unique address called an IP (Internet Protocol) address, a series of numbers specific to that device. When your device communicates with other devices over the internet, small packets of data are transferred between your device and whatever it's communicating with. Just as a postman needs your address before he can deliver your mail, so your device needs a unique address before it can communicate over the internet.

Until recently, devices had been assigned an IPv4 address. When IPv4 was designed, every device on a network had its own specific IP address, which meant every device could communicate with every other device on that network and on the internet. An IPv4 address, which looks something like this:, has 232 possible combinations (or 4,294, 967, 296). However, some smart chap realised that even though that provided more than four billion possible unique combinations, we were going to run out of IPv4 addresses pretty soon.

To conserve IPv4 addresses, routers began recycling IP addresses by assigning the same addresses to connected devices. This meant a number of devices that were connected by a private network shared a single address. While this slowed down the rapid decrease in available addresses, it hampered communication as devices on one of these private networks weren't able to effectively communicate with specific devices over the internet.

By February 2011, all the available combinations of IPv4 addresses were either allocated or used up. You may have noticed that the internet didn't come crashing down around us, and that's because of IPv6. An IPv6 address, which can look something like this: 2001:5c0:1000:b::1d67, has a possible 2128 combinations (or 340,282,366,920,938,000,000,000,000,000,000,000,000), which probably means we aren't going to run out of unique addresses any time soon.

IPv6 works by assigning a subnet of these addresses to every router that it can then use as a pool to assign to its devices, eliminating the private network problem that exists in IPv4.

So what does this all mean, and how does this affect Actrix customers?

Currently IPv4 and IPv6 are running in unison. While IPv6 is definitely the way forward, IPv4 will be around for the foreseeable future. The majority of routers these days are able to continue running IPv4 addresses as well as the new IPv6, so there's no need to rush out and upgrade your router.

Actrix will be implementing what is known as Dual Stack, which means every customer will get both a single IPv4 address and an IPv6 subnet allocation, so older technologies still using IPv4 will work alongside newer technologies using IPv6.

Furthermore, when you use a device to connect to the internet, most web browsers have been programmed to try an IPv6 connection by default. If this doesn't work, it will fall back to an IPv4 connection.

There is no foreseeable sudden cut-off to IPv4. Eventually all devices will utilise IPv6, but you will likely see little to no change in online functionality and service.



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