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Looking in more detail at the impact hoiur by hour on January 30th we get the Figure below. IT shows the hourly average RTTs on January the 20th from SLAC to 30 impacted hosts in 17 countries. 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. 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, 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.
