[T]here are four actual physical cables that deliver connections from the global Internet to Syria. [As seen in this map via Renesys, t]hree of them are underwater, in the Mediterranean Sea. The other comes across the Turkish border. To completely stop the Internet in the manner observed, all four would have to be severed simultaneously, an unlikely logistical challenge for the rebels, and one that still wouldn’t fully explain the systematic shutdown observed by technology companies elsewhere.
Jillian C. York adds:
Unlike in Egypt, where the government had to force or coerce internet service providers (ISPs) into shutting down, the Syrian government only allows ISPs to operate within the network infrastructure of STE, the Syrian telecommunications establishment. What this means is that private ISPs cannot have their own international links, allowing STE – which is state-owned – to effectively control all traffic. A network shutdown is as easy as one switch.
Jon Tullett puts the outage in context:
Although states usually fail to control Internet communications (unless they have a true established dominance like in North Korea), this doesn’t stop them trying. In most cases, sudden Internet termination is one of the final steps of a failing regime. In the revolutions of the Arab Spring, which kicked into high gear in 2010, this was particularly apparent, and Syria’s blackout is following a now-familiar path.