It’s ten years just now since the IETF really got the ball rolling and said it was time to create a new standard for the next generation of IP. But ten years later on, is there still a need for IPv6, and is anyone using it?

Why v6?
One of the prime driving forces for the development of a new protocol for the Internet was the fact that we were running out of IPv4 addresses. When the Internet first started up, nobody had any idea how ubiquitous it would become and no effort was made to conserve addresses. The way that addresses were arranged, using subnet masks to define network and host ranges, too, led to wastage. It was becoming increasingly likely, in the early 90s, that we would run out altogether.

Well, we still don’t have the IP address allocation for our fridges and dustbins that was expected -although I do know someone who has IP-enabled his doorbell and garage and has set up a web cam on his porch so that he can see if someone is trying to deliver a parcel and can open his garage door from work so that they can leave it safely - honestly! And now we use NAT pretty widely, so it could be argued that we don’t have the same need for millions more addresses.

But there’s more to IPv6 than lots more addresses. We’ll look into the details in forthcoming articles, but it can offer address autoconfiguration, hierarchical design support, and has improved security, mobility, multicast and quality of service functionality. Despite being more feature-rich, the IPv6 header format is actually simpler than its v4 equivalent, with fixed size headers that lend themselves to hardware parsing for faster processing.

Who’s using it?
So it seems that it’s not if but when that we’ll all become experts in the tricks of 128-bit addressing schemes. There are IPv6 stacks for most OSs (though only the newest versions) and router vendors, which have supported IPv6 in software for some time, are now starting to support it in hardware too, so you can get decent throughput figures. And if you do feel like trying it out, analysers such as Ethereal can decode IPv6 packets now.

It has to be said that there aren’t many commercial implementations of IPv6 networks out there yet. However, there are a significant amount of trials and test deployments, and they are carrying real data. As of this month, 62 countries worldwide have some sort of IPv6 presence. Most of these are research and academic institutions and service providers - there are various projects where IPv6 networks have been built, usually by tunnelling v6 over the standard IPv4 Internet, although there is a move to native v6 networks.

For instance, the 6Bone was probably the first IPv6 network to be deployed. Established in 1996 by the IETF as a test bed for IPv6 systems, it was made up of IPv6 islands, connected via tunnels over the existing Internet infrastructure. With more than 30 sites just within the UK (including at BT, Demon, UUNET and a link into JANET), the 6Bone has now fulfilled its purpose, to allow IPv6 testing, and will be disbanded over the next few years, as, according to the IETF “IPv6 reaches production status”.

Other live trials of IPv6 include 6NET and Moonv6. Unsurprisingly,given the preponderance of US IP addresses, the enthusiasm for IPv6 is less in the US than in Europe and, particularly, Asia, where the ability to give IP addresses to everything that has a chip in it is a popular driver.

Teliawas the first Service Provider, back in 2001, to build an IPv6 network to which commercial users could be connected. Those carriers who are less keen to start running IPv6 over their core networks, can, if you ask them, tunnel customers' IPv6 data over IPv4, using statically configured tunnels or automatic tunnelling mechanisms (where the lower part of the IPv6 address is used as an IPv4 address). There's also something known as 6to4, which uses public IPv6 to IPv4 gateways to translate between the two worlds. And 6PE, which runs on MPLS PE routers, means that nothing in a carrier's MPLS core even needs to know that IPv6 exists.

It will undoubtedly be some time before IPv6 is at all common. However, it is starting to gain momentum, so it's probably worth learning a bit of what it can and can't do, and what impact it could have on your network and systems. Forewarned is forearmed!

More information can be found at the IPv6 Forum website.