Moments after the news broke that two aircraft had crashed into the
World Trade Centre towers yesterday (11 September), telephone
communications on the US east coast ground to a halt and worldwide
Internet traffic surged.
As the day wore on it became clear that, although thousands of
lives had been lost, the telecommunications infrastructure in the
US was essentially operational.
By the time reports told the world that the Pentagon building had
been hit by a third hijacked airliner, less than an hour after the
World Trade Centre attacks, officials were urging residents to stop
making phone calls over both landlines and mobile phones in a bid
to keep lines free for emergency calls and for those frantically
trying to contact loved ones in the affected cities.
One national mobile operator reported that network call traffic
surged to 400% of its normal level in the two hours after the first
incident.
Many telecoms carriers, Internet service providers and network
vendors put security precautions into place, closely checking
employee identification cards or implementing other measures that
most declined to specify.
Verizon, a local fixed-line and cellular carrier that serves both
Washington and New York, said calls to the area doubled from their
normal peak volumes of 115 million in New York and 35 million in
Washington in the wake of the incidents.
Traffic on the cellular network was running between 50% and 100%
above normal levels. Verizon's directory assistance and operator
services were also overwhelmed, the company said in a
statement.
The initial attack knocked out as many as 10 base station sites
that used connections to land lines that went through the World
Trade Centre, Verizon said.
Verizon added that most of its 488 employees who work on the lower
floors of the North Tower of the World Trade Centre complex had
been accounted for.
By late afternoon, major carriers, including WorldCom, were
reporting that operations were running more smoothly, but under
emergency procedures.
Phone traffic to the US was also disrupted with carriers responding
to requests from their US counterparts to limit traffic.
Web traffic surged but the basic infrastructure held up. AOL, the
world's largest ISP, and hosting company Exodus Communications are
both based in Dulles, Virginia, near Washington. Both companies
reported that operations were not affected despite the surge in
Internet activity.
Perhaps most affected were news sites. CNN.com, part of AOL Time
Warner, could only be reached sporadically after news of the
tragedy spread.
The company responded by stripping graphics and links from the home
page and boosting bandwidth. Within hours the site was fully
accessible, as were the Web sites of other major media outlets,
including those of The Washington Post and The New York Times, both
of which provided frequent updates.
The spike in Internet use was, in fact, "relatively short-lived",
according to Matrix.Net, a Texas-based company that measures
Internet performance. IP traffic returned to "near-normal
performance levels within about an hour" after the initial spike in
traffic occurred.
The Internet "appears to have survived a severe test of the
adaptable traffic routing concepts it embodies", the company said.