IPv6 is the Future, and the Future is Now!

It’s Monday afternoon, and LISA is chugging right along! I’m well into my second day of training, and having a great time, and learning a ton that I’m going to take back to work.

After lunch, I’ve signed up for a training course that sounds great: “Beginning IPv6”. It's something that I’ve been very vocal about in the past. I’m convinced that by the time it’s obvious that everyone should implement IPv6, it will be too late to do it effectively. The most compelling argument to me is that the emerging markets of the world are going to be coming online using IPv6, because in short order, unassigned IPv4 blocks will all be assigned. That isn’t to say that providers aren’t sitting on blocks, but that it’s going to be harder and more expensive, therefore people who can’t buy them will go with the cheaper alternative that IPv6 will offer. They’re going to be your (and my!) future customers. I want to be ready in a couple of years, so I’m going out of my way to learn now. I didn’t learn IPv4 overnight, and I suspect the case will be made for IPv6 as well.

Rudi van Drunen started his presentation not with technical graphs of dwindling IP addresses. He started it with a slide with headers that said “Numbers run out” and “I need this turtle to dance”, and indeed, there was a CGI turtle. It wasn’t dancing. The turtle is from the KAME project. If you visit http://www.kame.net/ with IPv4, the turtle just sits there, but if you connect with IPv6, you get a dancing turtle. As Rudi said, let the dancing turtle be your incentive to implement IPv6.

As I mentioned, IPv4 addresses are running out. NAT has slowed the expansion, but it won’t be enough to quell the tide. IPv4 addresses are running out, and the internet is still expanding and smart phone use is exploding. We need more and more IP addresses. At this rate, our refrigerators are never going to get on the internet. And neither will the children of tomorrow.

In “IPv6…”, we went over the major changes from the IPv4 that we all know and love. The biggest change is undoubtedly the increase in IP address size. IPv4 uses 32 bit addresses. This provides just over four billion addresses. That sounds like a lot, but the 128 bit address space of IPv6 provides for 3.04x10^38 addresses. THAT is a lot of addresses.

Other changes that will influence networking are maximum transmission units (MTUs). The reason is that the typical MTU is 1500 bytes. With the previous IPv4 header taking up a scant 20 bytes, the larger IPv6 addresses double the header to 40 bytes. At least. Unlike the old version, IPv6 headers have multiple optional header additions. Looking at them from the outside in, each header holds a description of the next header inside of it. This provides the ability of nearly limitless plugins. This also leads to large headers, which can begin to take up an increasingly greedy chunk of the 1500 byte MTU. I forsee jumbo frames becoming more and more important as IPv6 becomes more prevalent and additional layers are implemented.

Speaking of additional layers, IPv6 provides the ability to add features into the protocol itself, through the use of these flexible headers. Where as IPv4 required specific packets to build and tear down IPsec tunnels, IPv6 has an optional header for ESP, encapsulating security packets. In other words, encryption. The header itself specifies that the packet contains encrypted information, rather than relying on encryption-protocol specific packets. This is exciting, and definitely makes me wonder about what new implementations will take effect once the protocol becomes more wide spread.

Overall, I’m still convinced that IPv6 is the future, and we’re going to need to learn it. The conversion isn’t going to happen overnight, and it’s going to take time to absorb the new environment. Why not start now with a lab environment and start learning? It’s not time wasted, it’s time invested in your future.

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By Matt Simmons, author of the Standalone Sysadmin blog