Recently in Natural Disaster Category

Faraway Fallout from Black Sea Cut

Last month, Wired.com's fascinating geological sciences blog, Eruptions, cast doubt on the purported cause of the December 23, 2012 failure of the Georgia-Russia submarine cable. That is, the author of the Eruptions blog post thought it unlikely to have been due to an undersea volcanic eruption. Without weighing in on the likelihood of active volcanoes in the Black Sea, we tweeted about some of the Internet impacts of this incident, although in 140 characters, we could only scratch the surface. We'll take a more in-depth look in this blog, noting shifts in traffic as far away as Oman, more than 3,000 kilometers distant!

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Hurricane Sandy: Outage Animation

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Renesys continues to analyze the impacts on Internet connectivity from Hurricane Sandy.


Here's another quick view of the impact on the routing table as Sandy came ashore Monday night. Each square represents the fate of a set of networks geolocated within a common tenth-degree square of the Earth's surface — at these latitudes, that's about 90 square kilometers.

At one end of the scale, the darkest green indicates better than 99.95% of the networks are available. At the other end, solid red indicates that more than 5% of the networks at that location have been removed from the global routing table, meaning that they can't be reached by anyone.

Five percent doesn't sound like much, but consider the Internet density in the affected areas! In fact, Manhattan's outage rates were much higher — on the order of 10%, which is impressively low given the fact that ConEd cut power to much of the island. Silencing ten percent of the networks in the New York area is like taking out an entire country the size of Austria, in terms of impact on the global routing table. The 90% that survive are in data centers, running on generator power supplied by engineers who do not sleep much.


It's striking to observe not only the impacts in NYC, Long Island, and New Jersey, but also peripheral weather-related outages in the Washington DC area, and up the I-93 corridor from Boston into New Hampshire. The Internet has become a sensor network in its own right for determining where storm damage is occurring — and since BGP routing converges in realtime, that information literally becomes available within a few seconds.



About the Renesys Blog

Our weblog is written by a variety of Renesys employees. They run the gamut from senior execs and engineers to sales guys. Anyone who has something to say that could be informative or of interest to our customers and visitors, says it here.

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