Between 1:45 p.m. and 3:30 p.m. Pacific Standard Time, many popular Web sites were either slower than usual to load or more likely not to load at all, according to Internet performance measurement company Keynote Systems. On a typical day, Web sites take less than 3 seconds to respond and can be loaded successfully at least 85 percent of the time.
The problem stemmed from hardware problems at Level 3 involving its Web hosting business and performance on its Internet backbone, Keynote said.
"It indicates a level of resiliency that may or may not exist with certain carriers," said Roopak Patel, senior Internet analyst at Keynote.
A Level 3 spokesman would not confirm or deny that hardware was the source of the problem, nor would he elaborate on the nature of the issue.
"We are investigating the cause of the problem, which is fully resolved at this time," said Arthur Hodges, the spokesman. He declined to offer additional information.
Keynote measures access performance for 40 companies that it considers the top business Web sites. The list includes Google, Yahoo, MSN, FedEx, Symantec, Hewlett-Packard and Dell.