Infrastructure
By Frank J. Derfler, Jr.
The new equation means always-on, always-connected access.
It's all about the connection. The communications connections among our computers, phones, PDAs, and other devices multiply our productivity and enjoyment, but each connection is a tool that simultaneously enables and limits. We've always wanted high speed, long distance, and low cost in communications. From the 1960s to the 1990s, we lived within an equation that said we were able to have any two at one time, but not the third.
High-capacity fibre-optic backbone circuits changed the equation in the late 1990s by diluting the importance of distance. In the US, companies like Global Crossing, Qwest, and Sprint had installed about 40 million miles of optical fibre by 1999.
The next big task in communications infrastructure is reducing the cost of high-speed portable access. We want cheap, fast connections anywhere, and this time we'll get it within a few years instead of decades. Today, many wireless options are available, but none are perfect. The wireless phone or PDA you buy this year probably isn't the solution you'll want in 2004.
Building Backbone
Before focusing on breakthrough wireless technology, we should recognise that to sustain the growth of the Internet and private networks, we must continue to develop the carrying capacity of fibre-optic backbone systems. Today, most optical multiplexers use a technology called wave division multiplexing (WDM), which allows up to 40 37Mbps channels on a fibre. New products that can put 80 channels on the same fibre are available from companies such as Lucent Technologies and Nortel Networks. Bell Labs, an arm of Lucent, is using dense WDM to demonstrate 1022 channels running over a single fibre. Another company, Avanex, can demonstrate DWDM transmission at three terabits--that's about three trillion bits--per second over a single fibre.
Flexibility is another modern goal in backbone systems. New devices called wavelength add/drop multiplexers, introduced by nec and others, give carriers much more flexibility in how they arrange their high-speed circuits. Alcatel sa recently demonstrated the ability to carry 80 channels of 10Gbps traffic over 3000 kilometres.
With such tremendous capacity, a new bottleneck appears at the switch level. Photonics, or optical data handling, accomplishes switching of data packets using light and mirrors. Companies such as Avanex, Bookham Technology, jds Uniphase, Lucent, and Nortel are developing products and investing in this area.
Despite the importance of optical backbone systems, we've already achieved the systemic benefit of optical technology's improved capacity and flexibility. To change the communications equation again, we need to work on high-speed portability--and that means wireless.
