Will the web run out of numbers?

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 Vint Cerf has been working with the internet since the 1970s 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.  BBC NEWS