Andrew M. Odlyzko, a professor at the University of Minnesota, estimates that digital traffic on the global network is growing about 50 percent a year, fueled by the increasing visual richness of online communications and entertainment — video clips and movies, social networks and multiplayer games.

But it basically corresponds to the improvements that technology is giving us, he says, as router computers for relaying data get faster, fiber optic transmission gets better, and software for juggling data packets gets smarter.

Tim Pozar, an engineer and a co-owner of the Internet services company UnitedLayer in San Francisco, said a number of forces were combining: the surge in bandwidth-hungry video applications on Web sites, the need to handle traffic from more Internet-enabled devices like cellphones, and shortages of electrical power for data centers in places like San Francisco.