Japanese Earthquake and P2P Disruption

Mar 17, 2011: Despite the damage incurred by the earthquake last Friday, P2P usage in Japan was only temporarily affected.

Over the past week, multiple sources have reported that Japan's Internet services are still working, despite the damage suffered by some underwater communication cables during the Sendai earthquake and tsunami. To capture the extent of the impact from the perspective of our users, we looked at the number of online users before and after the event.

To see how BitTorrent usage was affected relative to typical activity patterns, we compared data from the week of the earthquake with data from the same time in the previous week. In the graph on the right, the yellow line represents the number of peers found between Wednesday March 2nd and Sunday March 6th, while the blue line represents the number of peers online between Wednesday March 9th and Sunday the 13th -- the week of the earthquake. For the most part, the number of BitTorrent peers that we see in Japan is similar between the two weeks.

The exception can be seen in the 24-hour period immediately following the earthquake, which occurred at 2:46PM local time on Friday, March 11th. As the graph shows, the number of BitTorrent peers found online differed by as much as 25% in this period compared to the previous week at the same time. Surprisingly, we still see a large number of peers online and activity returns to normal on Saturday morning.

We are carrying on additional analysis to better understand how these events affected not only Internet connectivity and performance for people in Japan, but also for users in other countries, as a result of the damaged communication cables and rerouting of network paths.

Local Time
# of Peers in Japan
Number of peers seen in Japan (per hour), comparing usage on the week of the earthquake (March 9-13) to that in a typical week (March 2-6). The shaded region is a 1-day period starting at the time of the quake.

Impact of Virgin Media P2P Upload Throttling

Mar 11, 2011: P2P throttling trial cuts upload speeds by as much as 50% during peak hours of the day.

Virgin Media, an Internet service provider in the UK, recently completed a week-long test of its new upload bandwidth throttling policy that targets peer-to-peer traffic during peak usage times. Virgin plans to make the policy permanent if they deem the trial to be successful.

We find that this policy reduces users' upload bandwidth by as much as 50%, based on anonymized statistics contributed by P2P users inside the Virgin network.

On weekdays in the week before the throttling trial, users consistently used about 40% of their upload capacity. However, during the test (when P2P upload rates were throttled from 5PM to midnight), the maximum upload speeds we observed were significantly lower, sometimes only 20% of their capacity. The most significant reduction in speed occurs between 8PM and 10PM.

We also see that weekend upload rates were significantly reduced during the throttling period, from noon to midnight. Starting at about noon, our data shows a significant drop in upload speeds, from about 50% at 11AM to below 30% at 2PM. Later in the evening during throttling (at 10PM), upload rates fell to below 20% of capacity. In comparison, upload speeds before the trial averaged about 40% of capacity throughout the day.

Hour of day
Peak upload speed
(% of advertised)

Weekday upload speeds for Virgin Media customers in the week before ("No Throttling") and the week during the trial ("Throttling"). Shaded area shows the time when traffic management is enabled, from 5PM to midnight.


Hour of day
Peak upload speed
(% of advertised)

Weekend upload speeds for Virgin Media customers in the weekend before ("No Throttling") and the weekend during the trial ("Throttling"). Shaded area shows the time when traffic management is enabled, from noon to midnight.

Egypt and Libya Internet Disconnections

Mar 10, 2011: Internet shutdowns in Egypt and Libya are reflected in BitTorrent connections (or lack thereof).

Prompted by news of the governments of Egypt and Libya shutting down Internet access, we examine these events as seen from BitTorrent and captured by users of some of our software extensions - including Ono, NEWS, and Dasu.

Both graphs below show the number of BitTorrent peers seen for each country, per hour, before and after Internet access was cut off. In each case, we can clearly see a sharp drop in the number of connected users in those countries, to the point that each country almost completely disappears from BitTorrent. These drops coincide with the times reported by other sources that each country cut off its Internet connection (which are depicted by the shaded regions).

Time (UTC)
# of Peers
Number of peers seen in Egypt (per hour) from January 25th to the 31st. The shaded region begins when Egypt first went offline according to BGPmon.net (January 27th at 22:28 UTC).

Time (UTC)
# of Peers
Number of peers seen in Libya (per hour) from February 25th to March 7th. The shaded region begins at the time when Google and renesys reported Libya going offline (March 3rd at about 16:30 UTC).