2022 only has 19 days of existence but so far this January, there have already been four significant Internet disruptions:

1. An Internet outage in The Gambia because of a cable problem.
2. An Internet shutdown in Kazakhstan because of unrest.
3. A mobile Internet shutdown in Burkina Faso because of a coup plot.
4. An Internet outage in Tonga because of a volcanic eruption.

The latest Internet outage, in the South Pacific country of Tonga (with 169 islands), is still ongoing. It started with the large eruption of Hunga Tonga–Hunga Haʻapai, an uninhabited volcanic island of the Tongan archipelago on Friday, January 14, 2022. The next day, Cloudflare Radar shows that the Internet outage started at around 03:00 UTC (16:00 local time) — Saturday, January 15, 2022 — and is ongoing for more than four days. Tonga’s 105,000 residents are almost entirely unreachable, according to the BBC.

When we focus on the number of requests by ASN, the country’s main ISPs Digicel and Kalianet started to lose traffic after 03:00 UTC and by 05:30 UTC January 15, 2022, Cloudflare saw close to no traffic at all from them, as shown in the graph below.

Looking at the BGP (Border Gateway Protocol) updates from Tonga’s ASNs around the time of the outage, we see a clear spike at 05:35 UTC (18:35 local time). These update messages are BGP signalling that the Tongan ASNs are no longer routable. We saw the same trend in The Gambia outage of January 4, 2022 — there you can read about the importance of BGP as a mechanism to exchange routing information between autonomous systems on the Internet, something that was also seen in the 2021 Facebook outage.

BGP updates from Tongan ASNs around the time of the outage.
BGP updates from Tongan ASNs around the time of the outage.

Cloudflare Radar data doesn’t show any significant disruptions for Internet traffic in Tonga’s neighbours American Samoa (although there was a small decrease in traffic on Friday and Saturday, January 14 and 15, 2022 in comparison with the previous week) and Fiji. In American Samoa, all schools were closed on Friday, January 14, because of severe weather, and on the same day, after the volcanic eruption, there were tsunami warnings and evacuation to higher ground was advised (that continued through the weekend).

Tonga, as a geographically remote Polynesian country more than 800 km from the Fiji archipelago, is highly dependent on the Internet for communications. That is something that was improved five years ago with an infrastructure connectivity program from the World Bank. Prior to that, the country was dependent on satellite links for Internet that included a very small percentage of the population.

Repairs could take a few weeks

Southern Cross Cable Network confirmed that the 827 km fiber-optic undersea communications cable connecting Tonga to the outside world may have been broken. The company is assisting Tonga Cable Limited (TCL), which owns the single cable that provides Internet access and almost all communications to and from the archipelago.

The eruption resulted in a fault in the international cable 37 kilometres from Nukuʻalofa (Tonga’s capital), and a further fault in a domestic cable 47 km from the capital.

TCL announced that it has already met with the US cable company SubCom to start preparations for SubCom’s cable repair ship Reliance to be dispatched from Papua New Guinea to Tonga, possibly via Samoa (more than 4,000 km away).

The repairs could take "at least" four weeks, given that a repair to a fiber-optic cable that has been cut on the seabed is considered more complicated than misconfigurations, power outages or other types of infrastructure damage. “The site conditions in Tonga have to be assessed thoroughly because of volcanic activities,” according to TCL chairman Samiuela Fonua.

Fonua also mentioned that the last cable cut (back in 2019) took nearly two weeks to repair, but this time the site conditions will determine the time it will take — the two cables are not far away from the eruption site (the volcano is still active). According to ZDNet, in 2019 Tonga signed a 15-year deal with Kacific for satellite connectivity, but since then the satellite provider says it is waiting on the Tongan government to activate its contract.

Svalbard Undersea Cable System also disrupted in January

Also in January, Space Norway, the operator of the world’s most northern submarine cable — the Svalbard Undersea Cable System — announced that on January 7 it located a disruption in one of the two twin submarine fiber optic communication cables connecting Longyearbyen with Andøya north of Harstad in northern Norway (in the area where the seabed goes from 300 meters down to 2,700 meters in the Greenland Sea). A repair mission is being planned.

A world of undersea cables for the world’s communications

A significant amount of Internet traffic is carried by a complex network of undersea fiber-optic cables that connect countries and continents. The full submarine cable system (the first communications cables laid were from the 1850s and carried telegraphy traffic) is what makes most of the world’s Internet function between countries and continents. There are 428 active submarine cables (36 are planned), running in an estimate of 1.3 million km around the globe.

World map of submarine cables. Antarctica is the only continent not yet reached by a submarine telecommunications cable. Source: TeleGeography (www.submarinecablemap.com)

This gives a sense that the Internet is literally a network of networks in a world where estimates indicate that around 99% of the data traffic that is crossing oceans is carried by these undersea cables (satellite Internet, so far, is still residual — SpaceX has around 145,000 users).

The reliability of submarine cables is high, especially when multiple paths are available in the event of a cable break. That’s not the case for the Tonga outage, given that the 827 km submarine cable only connects Fiji to the Tonga archipelago — Fiji is connected to the main Southern Cross Cable, as the next image illustrates.

Submarine Cable Map shows the undersea cables that connect Australia to Fiji and the following connections to other archipelagos like Tonga. Source: TeleGeography (www.submarinecablemap.com

The total carrying capacity of submarine cables is enormous (EllaLink, the optical submarine cable linking the European and South American continents, for example, has 100 Tbps capacity) and grows year after year as the world gets more and more connected. For example, Google has recently finished a new cable with 350 Tbps of capacity. But, a transoceanic submarine cable system costs several hundred million dollars to construct. One of the latest, between Portugal and Egypt, with a total of 8,700 kilometers, is budgeted at 326 million euros.

The Tonga outage was not the only one of 2022 (so far) that happened because of cable problems. The Gambia outage that affected the country's main ISP, Gamtel, was because of “a primary link failure at ACE”, the cable system that serves 24 countries, from Europe to Africa, namely in the points of cable connections from Senegal to The Gambia.

In spite of these two fiber cable problems being separated by a few days at the start of 2022, Internet outages are more common because of situations like misconfigurations, power outages, extreme weather or the frequent state-imposed shutdowns to deal with unrest, elections or exams — recently this was the case of Sudan or Kazakhstan.