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Internet connectivity to the hosts PingER monitors in Japan was maintained. Round Trip Times (RTT) to some hosts increased significantly as seen from SLAC. However as seen from RIKEN in Japan they did not increase. It appears the increase in RTT depends on the route from the monitoring host to Japan. This suggests a possible cable disruption. For more on cables see here.
While the Internet appears to have kept running remarkably well (though some end hosts were not reachable a day later), the phone network did not fare so well.
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