One of the great mysteries of the Egyptian crisis was the ability of the Mubarak government to disrupt internet services, in a vain effort to disrupt protests. James Glanz and John Markoff have written a fascinating account in the New York Times about that phenomenon, and exactly how and why it occurred:
The strength of the Internet is that it has no single point of failure, in contrast to more centralized networks like the traditional telephone network. The routing of each data packet is handled by a web of computers known as routers, so that in principle each packet might take a different route. The complete message or document is then reassembled at the receiving end.
Yet despite this decentralized design, the reality is that most traffic passes through vast centralized exchanges — potential choke points that allow many nations to monitor, filter or in dire cases completely stop the flow of Internet data.
China, for example, has built an elaborate national filtering system known as the Golden Shield Project, and in 2009 it shut down cellphone and Internet service amid unrest in the Muslim region of Xinjiang. Nepal’s government briefly disconnected from the Internet in the face of civil unrest in 2005, and so did Myanmar’s government in 2007.
But until Jan. 28 in Egypt, no country had revealed that control of those choke points could allow the government to shut down the Internet almost entirely.
In the end, finding the “off switch” for the internet hardly saved the Mubarak government, but other authoritarian regimes were probably watching and taking notes.