Clearly, the new approach that considers PTR-records presents very different results. In most cases not only does the central region’s AS change, but the percentage is entirely different. In all of the generally reliable (from the global availability point of view) regions, the number of PTR-enabled IP-addresses that shut down following an outage of one autonomous system is dozens of times higher. This could mean that the leading national ISP always handles end-users. Thus, we should assume that this percentage represents the part of the ISP’s user base and customer base that would go offline (if switching to a second internet service provider were not possible) in the event of an outage. From this perspective, countries do not seem as reliable as they appear from the transit point of view. We leave possible conclusions from this PTR-enabled rating to the reader.

Details into Regions

Last year we clearly showed the significant influence of Cogent’s AS 174. This year, with 90% of the rating unchanged compared to last year, when Cogent served such regions as France, Great Britain, United States and Ireland, we see all those countries in the same position with the same upstream issues. The changes that did occur, however, were seen in the United States, where the CenturyLink AS 209 replaced Cogent. In response, Cogent added Spain and Belgium to the list of countries where it represents the dominant worldwide connection medium.

Although this means that Cogent’s shutdown represents a risk to multiple regions, it is also necessary to recognize that this particular ISP’s market position results from its good IPv4 connection. Even though Cogent added 2 countries to its portfolio, its denial of service would not lead to total unavailability in those highly diversified national internet segments.

However, the big news involving Cogent comes from the United States. For two years — 2016 and 2017 — we identified Cogent’s AS 174 as the crucial one for that market. This is no longer the case — in 2018, Cogent has been replaced by the CenturyLink AS 209, and the change sent the United States up the list by three places, to 7th.

Turning to the former USSR region, we see little change from a year ago with the primary internet service provider in Russia remaining Rostelecom (AS 12389), whose market share is quite significant. However, in 2018 Rostelecom’s outage would lead to only 5.27% unavailability, putting Russia in 13th place on the reliability list.

As in last year Russia’s transit market mostly comprises mid-sized Tier-2 networks, resulting in such high availability across the market. The same cannot be said of Uzbekistan, where we observe for the third year in a row a 99.9% dependency on a single AS (28910). Turkmenistan also has just one upstream provider available: Rostelecom. Tajikistan’s index is “way” better with a 78.14% instability index, placing it 202nd on the global reliability list. The fourth country of the region with high instability is Azerbaijan, although its 47% dependency on AS 29049 is not so bad compared to the others.

Ukraine’s fall in the ranking by four places can be explained by the ongoing legislative processes within the country as leaders try to determine the appropriate level of internet regulation to apply. It is not surprising that such interference leads to some loss of reliability, though Ukraine’s position in the top-20 is quite firm.

There are “only” 83 countries with over 40% dependency on a single ISP. 65 of those are above 50%. There are 39 usually small countries with instability indices over 90%. There are exceptions though: North Korea’s index is 100% for the AS 131279, which needs no explanation; the same applies to Eritrea, Greenland, and New Caledonia, although the reasons may be different. Ethiopia’s 99% dependency on a single AS 24757 (EthioNet) with a population of 100 million is quite surprising in 2018. Syria is 99.5% dependent on the AS 29256, which is a huge loss from last year’s 88.75% caused by the departure of the German AS that was the market leader. Cuba has an index of 97% with great instability due to its dependence on AS 11960. Jamaica’s index is 91.3% for AS 23520 owned by Columbus Networks, the company we often encounter as the sole provider for microstates in the Americas.

Compared to Luxembourg in 30th place with 9.8% dependency on AS 6661, Monaco has an index of 66% (AS 6758), which is peculiar for a country of such wealth and geography.