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Introduction
Automating detection
To spot the shutdown of a country automatically would take a bit of mining. For example, the country should have 2 or more target hosts and if all the targets in a country go offline (not reachable) in the same time frame then that is an indicator that something is probably happening and worth investigating. Of course, that assumes the Measurement Agent (SLAC) also was not down (due to maintenance etc.) at the same time. One can tell from say https://www-iepm.slac.stanford.edu/pinger/sites-per-country.html how many targets there are by country.
Outages that make hosts unreachable are relatively easy to detect since they exhibit 100% loss. Nowadays however, there are often backup routes so that the host stays connected even though a route may not be working. In this case, there is usually a step-change in the minimum RTT since the new route has a different distance to the original route. Also, the new route may have different capacity and will be shared by a greater number of conversations, thus it is likely to be more congested than the original route so the jitter and average RTT may change.
All hosts in a given country may not use the same carriers and thus have different routes so one needs to look at all hosts in a given country.
Some of the outages are all day(s) which would make it easier to detect. Shorter outages would be trickier. On the other hand, if we know of outages then we can look at the data around that time to see the impact.
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Some Examples
Cable cuts
In January 2020 there were two cable cuts along the west coast of Africa that affected sites in Southern Africa, see: South Africa damage to the SAT-3 and WACS undersea cable Jan 16 2020. In this case there was no 100% packet loss since the routes automatically switched to alternate-working routes, however, there was significant step change in the minimum RTT.
Another example is the impact of the Japanese Earthquake and Tsunami March 11th, 2011. Again there was a significant step change in the RTTs from SLAC to many Japanese hosts and new routes were chosen to avoid damaged cables to the US.
Also see Effects of Mediterranean Fibre Cuts December 2008 and Effects of Fibre Outage through Mediterranean Jan 31st, 2008.
Political events
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Ethiopia Internet Disruption June 2019
According to https://twitter.com/InternetIntel following a coup attempt June 22nd the Internet in Ethiopia was largely unavailable for multiple days. This is shown below. Also shown are the outages June 11 - 14, June 2019. These correspond with the government shutting down the Internet (almost completely) to coincide with the country’s national exams.
Below is shown the daily packet loss (a dot means no pings were responded to) measured by sending up to 30 packets every 30 minutes.
Mauritania June 2019
According to https://twitter.com/InternetIntel there was a significant Internet disruption starting 15:30 UTC June 25th following controversy surrounding presidential elections over the past weekend. Below is the daily packet loss of three hosts in Mauritania measured by pinging them from SLAC.
Looking in more detail at the PingER Beacon host MR.NIC.N2 (AKA www.nic.mr) we see:
Syria June 2019
According to https://twitter.com/InternetIntel reporting on June 23 "Another 4.5 hour Internet blackout in Syria beginning at 01:00 UTC (4-8:30am local) for another student exam. 6th such outage this month. Next exam (& internet blackout) to occur in two days." This is seen in the plot below of the Syrian PingER Beacon host www.iust.edu.sy.
Iraq July 2019
On July 15th, Internet Intelligence reported three exam-related national blackouts in Iraq in the past week, see here. Outages intended to prevent cheating on student exams.
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