Appendix A

The Physical Structureof the Internet

Increasingly, I have been asked questions along the lines of “But how does my data get from London to, say, Toronto?” To fully grasp how this happens it is necessary to have an understanding not just of the technologies involved but also something of the physical structure of the Internet. For reasons of simplification, in some of the following paragraphs I have combined examples from both the United States of America and the models usually found in European cities.

To comprehend this physical structure let us examine the recent rapid growth of the Internet from the perspective of the various service suppliers and telecommunications companies that are involved.

Back in the mid-1980s the Internet ...

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