Developments in DWDM in recent years have given the impression that the cost of providing bandwidth will soon be so low that there’ll be no point in making a big song and dance about using it efficiently.

Guess what? That’s dead wrong, according to a leading light in optical research, Professor David Payne, head of the Optoelectronics Research Center at the University of Southampton in the UK.

Payne says it’s vitally important to use bandwidth efficiently because we’re going to run out of it surprisingly fast. “Bandwidth is like health care. You can never have enough,” says Payne, one of the inventors of the Erbium Doped Fiber Amplifier.

Payne bases his argument on supply and demand calculations that illustrate that growth of Internet traffic will overwhelm telecom infrastructure within the foreseeable future.

On the supply side, he sees the following developments boosting bandwidth:

- the average cable will have 128 fibers rather than 8
- the number of wavelengths per fiber will rise from 1 to 512
- the bandwidth per wavelength will increase from 2.5 to 40 Gbit/s
- mesh will replace ring topologies, doubling effective capacity

When all of these effects are multiplied together, they add up to a 204,517-fold increase in the overall capacity of the average telecom network.

More than enough for anything? Not so, says Payne, who reckons all of that huge amount of extra capacity will be used up within four years if Internet traffic volumes continue growing at their current rate.

Right now, volumes are doubling every 100 days in North America and every 150 days in Europe, according to Payne. There's a strong likelihood that the this rate will increase in the future, as broadband access technologies such as DSL (digital subscriber line) and cable modems become more widely deployed.

It’s tough to believe that merely doubling Internet traffic every 100 days would create such a problem, but Payne has a way of illustrating the effect, using an example of grains of rice and a checker board. If a single grain of rice was put on the first square and the quantity was successively doubled on each subsequent square, the last square on the board would have to accommodate more than 18 million, million, million grains of rice, enough to cover the whole of the UK to a depth of more than 30 feet, according to Payne.

Payne notes that future developments in telecom aren’t likely to put off the capacity crunch for very long. The latest fiber developments from Lucent Technologies, Inc, for instance, might mean that DWDM systems can be cranked up to enable traffic volumes to be doubled another four times – equivalent to a mere 400 extra days of Internet traffic growth.

Hogwash? It sounds like it if you consider how much extra bandwidth an individual could use. If, say, the number of people using the Internet increased 100-fold - which might exceed the population of the planet - then the average person would see a 2,000-fold increase in available bandwidth, according to Payne's supply side calculations. As it happens, that's the rough difference between a 100-Mbit/s Ethernet connection and a dialup modem line. It's hard to believe that everybody will be wired up like that within a few years.

By Peter Heywood, international editor, Light Reading http://www.lightreading.com.