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Figure 1
Predicted World Wide Web bandwidth demand.

SOURCE: Data courtesy of the Internet Society.

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Figure 2
The ''last mile" bandwidth bottleneck.

factor of 10,000 in today's practice, which is based on time division multiplexing, the technical means are rapidly evolving to open up the full fiber bandwidth. This is the all-optical networking technology, based on dense wavelength division, in which different channels travel at different "colors of light."

So, why isn't it true that we already have the physical basis in place over which to send the traffic of the future? Most of the answer is summarized in Figure 2 2R. All the communication resources we have been installing seem to be improving in capacity by roughly 1.5 per year, totally out of scale with the 8-times-per-year growth of demand shown in Figure 1. The top curve of Figure 2 shows the capability of desktop computers to absorb and emit data into and out of the buses that connect them to the external world 3R. The next line shows local area network capacity as it has evolved. The third one shows the evolution of high-end access to the telco backbone that allows users at one location connectivity to users elsewhere outside the local LAN environment. The capacity of this third curve has been available only to the most affluent corporations and universities, those that can afford T1, T3, or SONET connections to their premises.



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