Page last updated at 06:16 GMT, Tuesday, 1 September 2009 07:16 UK

Will the web run out of numbers?

By Dave Lee
BBC World Service

Ethernet cable
Every time you hook up a new machine, another IP address is created

Every machine that is connected to the internet needs a unique identification number, or IP address.

The problem is that with more and more people going online these "IP addresses" are running out, and could be exhausted as soon as 2011.

Furthermore, a new system that would significantly increase the number of addresses has been slow to roll out.

Engineers Vint Cerf and Bob Kahn developed the current system in the 1970s. The pair used a 32-bit number, allowing for 4.3 billion addresses, and it is no longer enough.

"We're going to need more ways to uniquely identify things," Dr Cerf told BBC World Service programme Digital Planet.

"To do that we need to change the format of the way the packets of the internet move around and how they're identified."

Broadband boom

Dr Cerf has pioneered the use of Internet Protocol version six (IPv6), which has been waiting in the wings since 1998. IPv6 uses 128-bit numbers - which means 340 trillion, trillion, trillion addresses.

Vint Cerf
Vint Cerf has been working with the internet since the 1970s

That's enough for every person on the planet to have trillions of IP addresses

"It's enough address space to last until after I'm dead," explained Cerf. "And then somebody else has the problem."

The number of internet users is expected to double from the current figure of 1.6bn over the next few years. In China, there are more internet users than in the US - yet fewer than a quarter of Chinese people are online.

As the Chinese market booms and other countries come online, the old IP system will quickly reach critical mass.

But as yet, IPv6 is not in widespread use, largely because the infrastructure underlying many networks would need to be upgraded to accommodate the new protocol.

Governments all over the world are being pressured to upgrade networks to accommodate higher speed connections, which should help.

In the UK, the government recently outlined plans to offer 2 Megabits per second (Mbps) broadband to every household. This improvement comes at a price - everyone with a fixed-line telephone will be charged a "broadband tax" of 50p per month to cover costs.

Money matters

Could money spent on improving our internet speeds be spent in other, arguably more valuable places such as schools and hospitals?

Digital Planet is the weekly technology programme broadcast from the BBC World Service
It is broadcast on Tuesday at 1232GMT and repeated at 1632GMT, 2032GMT and on Wednesday at 0032GMT
It is also available as a podcast
It can be found on the social networks Facebook and Orkut

Dr Cerf argued that broadband is just as important.

"Remote health care will work much better if you have high-speed access to the internet," he said.

"You can send MRI images, you can send other information. You could provide information about your current state of health to someone who is remotely diagnosing.

"Education - same story. Broadband access gives you the ability to educate no matter where you are. The internet can be a big help in making learning a normal process for the rest of our lives.

"Broadband actually contributes to a lot of those things that we would like the government to support."

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