Zardon

WASHINGTON (Reuters) - Online computer services as far away as South Africa and Romania crashed after the Sept. 11 hijack attacks on New York's World Trade Center, but by and large the Internet performed well, a panel of experts reported on Wednesday.

On a day when telephone networks were frequently overloaded, e-mail and Web traffic mostly flowed smoothly despite the fact that vital Internet facilities in Manhattan were knocked out by the attack, the National Research Council said in its report.

"The fact is that the Internet, taken as a whole, was not significantly affected," said the report, which was drafted by a group of computer experts in academia and private businesses.

Web sites reporting news of the disaster struggled to keep up with demand and doctors in some hospitals found they could not access patient information on their handheld computers. Internet users in South Africa and Romania were knocked offline for days in some cases.

U.S. officials have worried that terrorists or hackers could try to bring down the global computer network that now handles much of the world's business.

Network engineers point out that the design of the Internet -- really a network of networks -- allows traffic to take alternate routes to avoid bottlenecks and trouble spots.

The National Research Council, which drew on a wide range of sources from Internet provider logs to public-opinion surveys to provide a comprehensive look at Internet activity on Sept. 11, seemed to support their point.

The report focused on New York, as the Pentagon attack in northern Virginia and the crashing of a hijacked plane in western Pennsylvania did not knock out Internet facilities.

Lower Manhattan serves as a hub for Internet traffic from all over the world, hosting scores of local Internet providers and undersea data cables serving much of Europe and Africa.

Several large Internet providers, among them WorldCom Inc WCOEQ.PK ., Verizon Communications VZ.N , and AT&T Corp. T.N , housed connection equipment in the World Trade Center's Twin Towers which went offline when the buildings collapsed. Additional facilities were lost when a nearby Verizon building was damaged by falling debris later that afternoon.

Additional problems sprung up hours later as the diesel-powered generators that provided backup power to many facilities ran out of fuel or became clogged with dust.

But engineers from rival companies worked together quickly to route traffic elsewhere, the report said. While some large Wall Street firms found they had no Internet service, others reported no problems.

Some overseas users ran into more difficulties. Internet providers in Germany, Italy, and Romania were knocked offline as they depended on facilities in lower Manhattan, the report said.

South Africa was perhaps hardest hit, as users found themselves unable to navigate the Web for several days after their domain-name system, which matches numerical addresses with easy-to-remember names like "www.example.za," was knocked out. The database for the names was located in Manhattan, the report said.

High-profile news sites struggled as well as they were swamped with visitors moments after the first plane hit. Network operators at CNN.com retooled the site to include fewer slow-loading graphics, and turned to Akamai Technologies Inc.'s AKAM.O distribution system for extra capacity.

Overall Internet use was slightly lower that day as people watched television to find out about the unfolding crisis, the report said. But figures from network monitoring facilities found that traffic as a whole flowed smoothly.