Why are we running out of IP addresses? (About IPv4 and IPv6)

IP addresses are what computers and other networked devices use to identify each other on the network. This network could be your home wifi network, with two computers, a couple of iphones, a printer, and your ADSL router, or it could be the entire internet, with millions of connected devices. IP (version 4 – the “normal” version) addresses are made of 32 bits (thirty-two ones and zeros), written in the form of four “octets” (8 bits, or ones and zeros), separated by dots. Each octet can be any number from 0 to 255, because this is the number of different potential combinations of ones and zeros if you have eight in a row, like 11001001, for example.

So, if each number can be 0-255, and you have four of these numbers, there are 4,294,967,296 different potential addresses. Nearly 4.3 billion. That’s quite a lot, but not enough.

A home network might use a range of IP addresses that look like 192.168.1.x (where x can be anything from 1 to 254), and a big business network might look like 10.x.x.x or 172.16.x.x. Because you can change the numbers where the x’s are, you can give your network the ability to have different numbers of things connected. Being protected from the internet (a “private” network), these addresses can be (and are) used over and over again in homes and businesses all over the world. There are internet “rules” that tell people what IP addresses you should use.

Just so you know, the address always means “loopback” or “localhost” or “home” – it’s commonly used for troubleshooting, as it is effectively the device’s own IP address. If you want to reach all the computers on a network, you use the IP address, or the “broadcast” address.

But on the internet, an address will more usually look a little different, and could be something like (google.co.uk), (this website), or (stanford.edu). Everything on the internet needs to have a unique IP address, from websites, email servers, itunes, internet radio stations, your iphone, and your home ADSL router. There are some clever ways that internet service providers conserve the number of IP addresses they need to use, by re-using IP addresses that haven’t been used in a while (which is why your home IP address may change every now and then), or using “network address translation” techniques (essentially giving out “private” IP addresses and re-routing them) so that multiple devices can use the same “internet” IP address.

However, partly because there are increasingly more and more devices connecting to the internet, more servers, and more websites, but also due to IP addresses being handed out in blocks (resulting in many not being used, but not available for use by anyone else), we’re running low. Current estimates put the running out date as early as February 2011, but by clawing back some of the wastage, and using Network Address Translation, the internet should be safe for a while.

Long term, however, we need a new system. That system is IP version 6, which instead of 32 bits per address, uses 128 bits, and therefore supports 2128 or approximately 3.4×1038 unique addresses. By comparison, this amounts to approximately 5×1028 addresses for each of the 6.8 billion people alive in 2010. Actually, the primary aim of IPv6 was not really to provide such a huge number of addresses, but rather to enable devices to more simply allocate addresses, improve routing efficiency (less requirement to fiddle around with address translation or port forwarding), and add clever features such as authentication and data integrity.

Oh, because I know you’ll ask, IPv5 was an experimental streaming protocol, which is why we’ve gone from IPv4 straight to IPv6.

Globally, IPv6 is still very much in its infancy, with largely only the internet big players such as google beginning to roll it out. If you have new hardware and Windows Vista or 7, however, you can use it quite effectively in your private home network. On the internet itself, there’s not that much around yet. Facebook have an IPv6 address at http://www.v6.facebook.com/ and google have theirs at http://ipv6.google.com/, but without an internet-facing IPv6 connection, you won’t be able to get to those links, yet, as there are some issues to be overcome in combining the two addressing protocols. Possibly the biggest and most notable use so far of IPv6 was the 2008 Olympic Games – http://ipv6.beijing2008.cn/en (IP addresses 2001:252:0:1::2008:6 and 2001:252:0:1::2008:8), and all the network operations of the games were conducted using IPv6.

In a few years’ time, we’ll all be using IPv6 in one way or another, by using 4G mobile phones, connecting our homes to high-speed internet, accessing new websites and web services, and more; though IPv4 is going to be around for a long, long time.

The constant battle between motorists and cyclists.

All this debate about cycling and motoring (usually presented as a confrontation between the two) is getting tiresome. I’m a motorist and a cyclist too, like many people. I don’t commute to work on my bike, but I ride for leisure and have ridden competitively. I ride off-road a lot, but also quite often on the road too
If we’re going to get anywhere with this debate, I think we need to agree on a few key points:
1. Cycling is good, and should be encouraged. It’s good for the environment, good for congestion, and good for the health and fitness of the cyclist.
2. Cyclists are vulnerable. With just a lightweight helmet and clothing for protection, motorists need to be aware that what might be a minor accident for them, can mean death or serious injury to a cyclist.
3. Cycling is hard work. The shorter a cyclist’s journey can be, the better. Stopping and starting is also hard work. In a car at traffic lights, a green light means you lift the clutch and push on the throttle, on a bike, you get up out of the saddle, pump those legs, and exert a lot of energy in order to get up to speed.
If all motorists were properly aware of those facts, they might not be in such a hurry to condemn cyclists. I know it can be frustrating to drive behind a cyclist, waiting for space to pass, and it can be a surprise to see a bike weaving their way through a queue of slow traffic, and sometimes around junctions, you have to wait for a cyclist to get out of the way before you turn right or left, but that doesn’t mean the cyclist isn’t aware of this. Cycle paths are often terrible. I’ll often ride on the road instead of a cycle path, because cycle paths can be so difficult to navigate. Lowered kerbs (especially on a lightweight road bike), potholes, convoluted routes around traffic junctions, and the way they seem to suddenly end and reappear a few hundred yards down the road all mean that the actual road is often a better place to ride.

specialized enduro mtb

Motorists and pedestrians alike seem to have a few regular things to say about cyclists:
“Cyclists don’t obey the highway code.”
Neither do motorists. Not all cyclists are angelic, considerate, and polite road users, but neither are motorists, and we don’t start every debate about driving with how many drivers exceed the speed limit, drive after a beer or two, drive recklessly or don’t pay attention. Why do it to cyclists?
Cyclists aren’t entirely without blame though. And I’m not *just* talking about the reckless, junction-skipping, red light jumping, no-lights or helmet ones. The cyclists that are too slow, too hesitant, and too timid are equally as bad. Be bold, obvious, and clear about your intentions, and you won’t have many problems with traffic. And don’t be an idiot.
“Cyclists jump red lights.”
I’ll admit to this. Partly because of item 3 above,  if it’s obviously clear and safe do so, I see no problem with a cyclist going through a red light, carefully and at an appropriate speed, bearing in mind that it’s their own welfare at risk.
“They ride the wrong way up one-way streets.”
One way streets and footpaths. I’ve cycled the wrong way up a one way street, when the alternative would be to add over 10 minutes to my journey – it’s no big deal to drive an extra half mile around a city centre to obey street regulations, but it’s a whole different matter on a bike. I’d only do it if it was clear, safe, and not busy, of course. This often applies to pedestrianised areas too. Of course, this wouldn’t be an issue if town planners took cyclists into account, but they so rarely do.
“If cyclists want to use the roads, they should pay road tax.”
We do. Most of us have cars too. And anyway, there’s no fiscal link between vehicle excise duty (road tax), and the roads themselves. Roads are funded by general taxation, so cyclists have paid just as much as motorists.
“Roads were built for cars, not bikes.”
Bikes were here before cars. Horses and carts before either.
“Motorists have to have insurance, so cyclists should too.”
Actually many of us do, through cycling clubs or as part of our other insurance policies. But this is a more complex issue than just insisting cyclists are insured. Cycling is cheap, and obliging cyclists to be insured would mean many either couldn’t afford it, wouldn’t bother, or would just go back to driving their car.
As a cyclist, I’d like to see better cycle routes, town planning that actually aids cyclists rather than hinders them, more encouragement for recreational and competitive cycling, and and better integration with public transport. If drivers could treat us with respect, that’d be great too. We need to encourage more people out on their bikes; if just 10% of motorists got out if their cars and into their bikes, imagine how much less congested the roads would be, how much healthier and happier we’d be as a nation, and we wouldn’t spending so much on petrol either.