The Story of Two Outages

by Louis Poinsignon.

Over the last two days, Cloudflare observed two events that had effects on global Internet traffic levels. Cloudflare handles approximately 10% of all Internet requests, so we have significant visibility into traffic from countries and networks across the world.

On Tuesday, September 5th, the government of Togo decided to restrict Internet access in the country following political protests. The government blocked social networks and rate-limited traffic, which had an impact on Cloudflare.

Internet traffic of Togo rate limited during protests in September 2017

This adds Togo to the list of countries like Syria (twice), Iraq, Turkey, Libya, Tunisia, etc that have restricted or revoked Internet access.

The second event happened on Wednesday, September 6th, when a category 5 hurricane ravaged the Caribbean Islands.

The affected countries at the moment are:

  • Anguilla
  • Antigua and Barbuda
  • British Virgin Islands
  • Puerto Rico
  • Saint Barthelemy
  • Saint Kitts and Nevis
  • Saint Martin
  • Sint Maarten
  • U.S. Virgin Islands

Losing the routes

Most of the network cables are buried underground or laying at the bottom of the oceans but the hardware which relies on electricity is the first one to go down.

Cell towers sometime have their own power source thus allowing local phone calls but without a backbone no outside access is possible.

The Réseaux IP Européens (RIPE) is an Internet registry that collects routes announced over the Internet and can display the reachability of a country.
A few networks went black in Saint Martin island. Orange Caraïbes announced in a press release that they repaired their network at 14:00 local time (18:00 UTC). On the graph we can see that it recovered at 19:00 UTC.

RIPE BGP Collection: Routes announced in Saint Martin during Hurricane Irma - September 2017

Losing the traffic

While the routers were going back online, the end-user traffic was severely reduced on the edge of Cloudflare.

Saint Kitts did not go offline, but traffic was reduced at 08:00 am local time on Wednesday.

Internet traffic of Saint Kitts during Hurricane Irma - September 2017

Both Saint Martin and Sint Maarten share the same island, which was one of the most affected by the hurricane. According to the New York Times, the island was badly hit at around 10:00 am local time on September 6th.

Internet traffic of Saint Martin during Hurricane Irma - September 2017 Internet traffic of Sint Maarten during Hurricane Irma - September 2017

Antigua and Barbuda started losing connectivity when the storm approached at 10:00 pm local time on Tuesday 5th September.

Internet traffic of Antigua and Barbuda during Hurricane Irma - September 2017

The U.S. Virgin Islands and Puerto Rico were also strongly affected.

Internet traffic of the U.S. Virgin Islands during Hurricane Irma - September 2017 Internet traffic of Puerto Rico during Hurricane Irma - September 2017

This final image shows the different times when the hurricane reaches every island:

Internet traffic of the Caribbeans islands during Hurricane Irma - September 2017

Conclusions

While the Internet was designed to sustain a nuclear attack and can re-route within seconds, islands are often isolated with fewer routing options for provider than on the mainland (3 or 4 instead of 10 or 15).
During natural events like this one, the Internet is crucial as a resource for communication, since people use it to tell their family abroad they are safe and to find shelter, food and clean water.

If you live in these islands and have Internet access, Google lists the shelters and has public alerts.

comments powered by Disqus