"The major Egyptian networks stopped announcing what networks they represented to the rest of the world," said Andree Toonk, the founder and lead developer of the open-source BGPmon, a tool for monitoring BGP, or "border gateway protocol," the protocol at the core of the Internet's routing mechanism.

The process likely took only minutes, and required simple changes to the country's core router configuration files, Toonk said. Earlier Friday, Toonk noted that more than because they had withdrawn their routing announcements.

Routers communicate with each other using BGP to establish pathways for digital traffic. By refusing to tell other networks how to reach their IP addresses, Egyptian Internet service providers (ISPs) effectively cut off all communication with the Web.

"You could call it a 'kill switch,'" Toonk said.

Beginning Thursday and accelerating Friday, to observers outside the country. Although early reports said it wasn't clear how the disconnect had been done, Toonk and others said today it was certainly by refusing to release BGP information to upstream providers and other networks on the Internet.