Hurricane Sandy caused failures in US internet infrastructure to double above their usual level, researchers have found.
The hurricane, which hit the East Coast of the US at the end of October this year, had a noticEable effect on the overall health of US internet infrastructure, researchers at the University of Southern California said on Monday.
"There are always occasional network outages in a network the size of the internet," the researchers wrote in their Preliminary Analysis of Network Outages During Hurricane Sandy paper (PDF). "We show that the US network outage rate approximately doubled when the hurricane made landfall, and that it took about four days to recover to prior levels."
Around 0.3 percent of internet infrastructure is down on any given day, the researchers wrote. Before Hurricane Sandy made landfall, around 0.2 percent of US connections were not working, but once the storm hit the East Coast, the percentage jumped to 0.43 percent.
The research demonstrates both the resilience of the internet - the technology was after all designed in the first place as a communications network capable of functioning after a massive Soviet nuclear strike - but also how it can still be affected by natural disasters.
To gather data for the study the researchers tried to contact a statistically significant portion of IPv4 addresses - around 0.3 percent - across the US before, during and after Hurricane Sandy.
Before Sandy, around 0.2 percent of US connections were not working. Once the storm hit, the percentage jumped to 0.43 percent
They found that the areas hardest hit by the hurricane had the worst drops in connectivity, with IPv4 blocks corresponding to addresses within New Jersey and New York demonstrating the greatest number of outages.
However they found that Connecticut and New Jersey were able to repair problems much more quickly than in greater New York, where residents suffered the longest period of downtime.
"Our work measures the virtual world to peer into the physical," John Heidemann, who led the research, said in a statement. "We are working to improve the coverage of our techniques to provide a nearly real-time view of outages across the internet. We hope that our approach can help first responders quickly understand the scope of evolving natural disasters."
In the age of the cloud, being able to pinpoint internet outages and their severity is attracting much attention: besides academic researchers, many companies are devoting technical resources to providing better information during outages, such as Compuware's recently-launched Outage Analyser.