Yesterday’s leap second caused “sporadic outages” in more than 2,000 networks that link machines across the Internet, according to a company that tracks the performance of online services.
Doug Madory, the director of internet analysis at the New Hampshire-based Dyn Inc., says the outages occurred just after midnight Coordinated Universal Time, when the leap second was added (see graph below). Because no single Internet service provider was responsible for the outage, Madory says, the leap second was almost certainly the culprit. “This is pretty unusual,” he says.
Leap second causes ~5 minutes of transient global routing instability pic.twitter.com/zw7xN3xazA
— Dyn Research (@DynResearch) July 1, 2015
Periodically, the world’s official time keepers add a leap second to the world’s official clocks to keep them in sync with spinning of the earth. For nearly fifty years, we’ve keep official time with atomic clocks—clocks that measure time via the oscillation of a cesium atom—that don’t account for small changes in the behavior of the earth. Time keepers have added 25 of these leap seconds since 1972.
The trouble is that the world’s computers, which rely on old and imperfect software code, aren’t always prepared to accommodate this extra second. After the last one, in 2012, web services such as Reddit went dark, as did machines at Qanta Airways, causing flight delays in Australia. Because of these outages, companies were apparently more prepared this time around. But according to Dyn, the extra second still caused an Internet hiccup that lasted about 5 five minutes. Some services may have been down for longer.
Apparently, says Madory, the hiccup that Dyn saw was caused by a particular Internet router, a device that routes information across the ‘net. “This would make sense, given the profile of the outage,” he says.
Basically, Dyn saw the outage in the exchange of data between large Internet services. There was a large spike in the number of messages traveling between the world’s ISPs and companies as they worked to reroute data after it was dropped traveling by certain paths.
Some have called for the abolition of the leap second, saying that we don’t need to recalibrate our clocks so often (even after 700 years, the clocks would only differ from earth time by about half an hour). The leap second can causes outages. But it also requires additional work in order to prevent outages.