Nov. 25, 2003 -- The Northeast blackout in August had a larger impact on Internet performance than initially thought, according to a new study from Renesys Corporation.
Renesys, an Internet monitoring firm, based its conclusions on a performance analysis of routers that helped direct traffic between 9,700 networks, which showed that 3,175 of those networks suffered connectivity outages.
Of those, more than 1,400 networks suffered severe connectivity outages that lasted longer than 12 hours, with some stretching beyond 48 hours. The most serious outages occurred in smaller networks, and were focused within the blackout area, where many residents had no power to turn on their computers or access the Internet.
But the connectivity outages were problematic for those who had backup power and were prepared to continue operations. Renesys study found that more than 1,000 businesses, agencies and universities had outages of all of their networks lasting longer than 4 hours.
"Reports that Internet was generally unaffected by the August blackout significantly understated the event's impact on the nation's emergent critical communications infrastructure," Renesys writes in its report.
Renesys noted that the outages were geographically localized, and said it "found no evidence of cascading failures affecting global Internet stability."
Facility problems included an extended outage at 60 Hudson Street, one of the busiest carrier hotels in New York, which struggled with generator fuel storage restrictions (stories here and here).
Some of the hardest-hit networks included Michigan Internet, which had up to 87 percent of its network down for more than 4 hours, while some outages at Toronto-based Allstream (formerly AT&T Canada) reached 84 hours, or three-and-a-half days. About 40 percent of UUNet's networks in the affected area were also down for 4 hours or more, according to Renesys' data.
Having multiple providers didn't always offer protection. Among the networks suffering outages was a "midsize Internet service provider serving businesses in Manhattan," which was down for more than four hours despite having nine different connectivity providers.