IPv6 has become a bit of a hot topic in the last couple of months. As of February 3, 2011, the last batch of 5 /8 address blocks were allocated to the Regional Internet Registries. These addresses could well be fully consumed within three to six months at current rates of allocation.

IPv6 was developed by the Internet Engineering Task Force (IETF) to deal with the long-anticipated IPv4 address exhaustion. The IPv6  RFC was published back in 1998. ISP’s, and certainly end-users, have been slow to adopt IPv6 until recently.

At Node4 we’ve been looking at IPv6 for about twelve months. Last year we built a small lab and did some research, but like the majority of other UK ISP’s we didn’t adopted it – primarily because our customers weren’t asking for it. However things have now moved on and at the beginning of the year we kicked off an internal IPv6 project to deploy it in to our network.

The purpose of this blog is to keep you, our customers, informed of our progress and to get you thinking about deploying IPv6 in your own networks.

So first to some basic questions:

Will the Internet stop working when addresses run out?
In a word no - IPv4 is going to be around for a few years to come.

Will there be enough IPv6 address?
I would hope so. IPv4 allows 32 bits for an Internet Protocol address, and can therefore support 4,294,967,296 addresses, IPv6 uses 128-bit addresses, so the new address space supports approximately 340 undecillion (or 3.4×1038) addresses.

I watched a web cast from LINX72 recently and one of speakers held up a box about the size of a house brick – he said that they had worked out that if the box represented all IPv4 addresses IPv6 addresses would be the mass of all the planets in our solar system!

As standard the regional registries are allocating ISP’s a /32 IPv6 prefix. With a recommendation that each customer is given a /48 prefix, that works out to approximately 65,000 /48 prefixes for each /32. So as you can see there are plenty of addresses to go around.

With this amount of addresses there is no need for NAT/PAT or private address space (although there are Link-local addresses which are akin to the private, non-routable addresses in IPv4). Every device can be given a globally unicast IPv6 address (Global unicast addresses, which are conventional, publicly routable address, just like conventional IPv4 publicly routable addresses).

Can I still get IPv4 addresses?
Yes at this time you can, however RIPE are being more stringent than ever with their allocation which means that ISP’s are being the same with theirs. If you can justify your use for the IPv4 addresses then you can still have them. As we make our way towards the end of 2011 it may get harder and harder to get a new allocation however no one knows exactly when all the addresses will run out. Therefore you should look to conserve and re-use exiting addresses by utilise Port Address Translation whenever possible.