Date: Nov. 20, 2002
Contacts: Barbara J. Rice, Deputy Director
Corbin Arberg, Media Relations Assistant
Office of News and Public Information
(202) 334-2138; e-mail <>

Internet Damage From Sept. 11 Terrorist Attacks in
New York City Was Limited, But Better Contingency Plans Are Needed

WASHINGTON -- The overall effect of the damage to the Internet on Sept. 11, 2001, when the collapse of the World Trade Center buildings destroyed communications equipment and networks, was minimal, says a new report from the National Academies' National Research Council. Internet service providers and users need to address some operational issues, however, to better prepare for and respond to future emergencies in light of the useful role the Internet played after the attacks.

New York City, one of the nation's most important communication hubs, is home to many Internet users, private data networks, and Internet service providers. Multiple fiber-optic grids run beneath its streets, and many trans-Atlantic cables come ashore nearby. Telecommunications facilities not only serve the many thousands of Internet customers in the city but also interconnect service providers throughout the region and in other countries.

"The terrorist attacks provoked a national emergency during which we could see how the nation and the world uses the Internet in a crisis," said Craig Partridge, chair of the committee that wrote the report, and chief scientist, BBN Technologies, Cambridge, Mass. "New York City is a 'super hub' of Internet links and services, and the collapse of the World Trade Center buildings damaged some of those links and services, often in subtle and surprising ways. Overall, the Internet displayed not only its resilience on Sept. 11, but also its role as a resource."

Serious effects on the Internet were isolated to New York City and a few other locations. Most of the damage was quickly remedied through improvisation, the rapid deployment of new equipment, and the rerouting of Internet traffic to bypass failed parts.

Although the events of Sept. 11 do not necessarily indicate how the Internet might behave in response to a direct attack on the network, they do shed light on possible vulnerabilities, the report says. Key businesses and services that use the Internet need to review their dependency on it and plan accordingly. For example, a New York City hospital learned that its doctors had come to rely on wireless handheld computers fed through an external Internet connection. When this link was briefly broken by the collapse of the towers, doctors had trouble accessing medical information. Contingency plans, more coordination with local authorities, and a means of restoring service remotely also are needed to better deal with electrical power failures.

As a whole, the attacks affected Internet services very little compared with other telecommunications systems. Telephone service was disrupted in parts of lower Manhattan, and cell-phone service suffered more widespread congestion problems. Nearly one-third of Americans had trouble placing a phone call on the day of the attacks. The Internet, however, experienced only a small loss of overall connectivity and data loss, the report says. With phone service impaired, some individuals used instant messages on their wireless handheld devices and cellular phones to communicate instead. Web sites were created to distribute lists of missing persons and other information to help people try to locate loved ones.

The attacks also caused a surge in demand for news reports. Television was the primary source of news for many, but the Internet provided another means. The Web server capacities of several major news services were briefly overwhelmed that day. For example, CNN's online network experienced nearly 10 times more traffic than the day before. To meet the demand, Web pages were simplified and capacity was added so that more Internet users could access the sites.

This study was sponsored by the Association for Computing Machinery's Special Interest Group on Data Communications, IBM Corp., and the Vadasz Family Foundation. The National Research Council is the principal operating arm of the National Academy of Sciences and the National Academy of Engineering. It is a private, nonprofit institution that provides science and technology advice under a congressional charter. A committee roster follows.

Read the full text of The Internet Under Crisis: Learning From September 11 for free on the Web, as well as more than 2,500 other publications from the National Academies. Printed copies are available for purchase from the National Academies Press Web site or by calling (202) 334-3313 or 1-800-624-6242. Reporters may obtain a pre-publication copy from the Office of News and Public Information (contacts listed above).

Division on Engineering and Physical Sciences
Computer Science and Telecommunications Board

Committee on the Internet Under Crisis Conditions: Learning From the Impact of September 11

Craig Partridge (chair)
Chief Scientist
BBN Technologies
Cambridge, Mass.

Paul Barford
Assistant Professor
Department of Computer Sciences
University of Wisconsin

David D. Clark*
Senior Research Scientist
Advanced Network Architecture Group
Laboratory for Computer Science
Massachusetts Institute of Technology

Sean Donelan
Internet Security
SBC Communications
Mountain View, Calif.

Vern Paxson
Senior Scientist
ICSI Center for Internet Research, and
Staff Computer Scientist
Lawrence Berkeley National Laboratory
Berkeley, Calif.

Jennifer Rexford
Technical Staff Member
AT&T Labs Research
Internet and Networking Systems Research Center
Florham Park, N.J.

Mary K. Vernon
Professor and Vilas Associate
Department of Computer Sciences and
Department of Industrial Engineering
University of Wisconsin


Jon Eisenberg
Study Director

* Member, National Academy of Engineering