For much of Wednesday, a chunk of the Internet traffic to and from Hawaii came to a halt, victim of a series of unusual circumstances.
The problem began when AT&T Corp. began shutting down part of the major undersea fiber-optic cable linking Hawaii and California to do routine maintenance.
A lot of the Internet traffic that goes between Hawaii and the mainland is routed through that cable, called Haw5.
When AT&T began its five-day maintenance project Wednesday, the company or other carriers that lease space on Haw5 diverted their affected telecom traffic - phone calls, Internet links and the like - to orbiting satellites. Normally, that backup works fine, AT&T and other companies say.
But when MCI Communications Corp., which handles about 45 percent of the nation's Internet traffic, rerouted its Hawaii communications to a satellite, something went wrong. The circuit carrying the Internet traffic shut down.
MCI's not sure why. "We've done that before," said company spokeswoman Leslie Aun of the satellite backup. "It's worked before."
The shutdown meant that customers of Internet providers and other businesses that use MCI's line could not access the Internet or experienced delays for much of Wednesday. When MCI discovered the problem, it was able to reroute the traffic to a secondary undersea cable, resuming normal service by late Wednesday, Aun said. That arrangement will be used until Haw5 is back in full service, scheduled for Monday.
Dave Johnson, an AT&T spokesman in New Jersey, said using satellites orbiting more than 22,000 miles away can cause problems when data is transmitted, such as during Internet communications. Garbled data or disconnections may occur.
But AT&T has received no complaints from carriers whose traffic it is rerouting, Johnson said.
Hawaii OnLine, the state's largest commercial Internet provider, said some of its customers experienced problems - mostly Wednesday - stemming from the Haw5 work or other factors that aggravated the situation.
Other online companies warned their customers of potential delays or outages.
"We all experienced problems to varying degrees," said Ron Lee, Hawaii OnLine general manager.
But Lee said the situation seemed to be settling back to normal on Thursday.