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Looking in more detail at the impact hoiur hour by hour on January 30th we get the map on the right in the Figure below. IT It shows the hourly average RTTs (z axis) by time of day (y axis) on January the 20th 30th from SLAC to 30 impacted hosts (x axis) in 17 countries identified by their Top Level Domain (TLD). In this graph the vertical (Average RTT) is chopped off at 2 seconds, though some hosts took up to almost 10 seconds to respond at times. It can be seen that the impact (sudden increase in RTT) is very abrupt. The time of the impact varies by 2-3 hours (between 4am and 7am). Most hosts continued to respond apart from 3 in Sudan and 1 in Bahrain, each of which did not respond for up to an hour. The magnitude of the impact also varies by more than an order of magnitude from country to country. By looking at the data for other days in particular Jan 29th (see the map in the left of the Figure below), we verified that the sudden increase was not caused by the normal diurnal variations of people coming to and leaving work etc. The thumbnail below shows the average RTTs for Jnuary 29th for comparison.
