The Internet Under Crisis Conditions: Learning from September 11 by National Research Council of the National Academies

Author:National Research Council of the National Academies
Language: eng
Format: epub
Tags: Computers and Information Technology : Internet and Networking
Publisher: NATIONAL ACADEMY PRESS
Published: 2003-01-31T00:00:00+00:00

Cellular Telephones

As word of the attacks spread, the cellular telephone system in the northeastern United States began to be heavily loaded. Nationally, call volume rose 50 percent above normal. One can compare this rate with the 30 percent increase typical on Mother’s Day, the canonical example of an exceptional calling day. Cellular telephone systems are usually engineered to support traffic during busy hours with only about 4 percent of calls being blocked (given a busy signal).

Regionally, the experience was even more dramatic. New York City had a 400 percent increase in call attempts during the day. At about 11:00 A.M., the volume was up 1,300 percent for at least one major carrier. Washington, D.C., had a 125 percent increase for the day. New England as a whole saw a 75 percent increase. The cellular system was not engineered for these loads, so call-blocking rates grew accordingly. In New York, 75 percent of calls were blocked (92 percent at the morning peak). In Washington, D.C., 56 percent of calls were blocked.

Wireless Internet—using such devices as Research in Motion’s Blackberry—also rose on September 11. Traffic surged by 60 percent around 10:00 A.M. and stayed high through the early afternoon.7

7From reports by carriers to the Federal Communications Commission.

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