A WorldCom spokeswoman apologised to customers and said about 20% of the company's IP user base in the US was affected. However, some analysts said Internet monitoring technology showed even more widespread problems in the US and abroad.
The breadth of the outage was substantial because WorldCom and its UUnet backbone network serve numerous Internet service providers, many with large customer bases of their own. WorldCom did not divulge how many IP customers it has altogether, but spokeswoman Jennifer Baker said the number is in the thousands.
Baker declined to name the maker of the affected routers and defended WorldCom's technical staff. "We believe we have very talented engineers and technicians that are monitoring our network and will continue to do that," she said.
Tom Ohlsson, vice-president of marketing at Matrix NetSystems in Texas, which monitors Internet services, said its global monitoring software indicated an "unprecedented" outage throughout the US, nearly all of Mexico and parts of Canada, Europe and the Pacific Rim.
Ohlsson said the 20% of customers with outages that WorldCom acknowledged involved Web sites that the company hosts itself. However, he added, Matrix's monitoring showed that the router problems also affected Internet services offered by Sprint and AT&T, which both use the UUnet backbone.
Some WorldCom customers had been nervous about outages even before last week's disruption, as a result of the company's financial difficulties and its Chapter 11 bankruptcy protection filing in July.
Greg Marney, chief executive officer of Northwest Open Access Network, a telecommunications wholesale company based in Washington state that provides transport services to rural areas, said his staff had started checking in weekly with WorldCom. "The real intent is to make sure that they are operating like we hope they will," Marney said.