Sustainability Survey of National Internet Segments for 2019

This study explains how the failure of one autonomous system (AS) affects the global connectivity of a particular region, especially when it comes to the country's largest Internet service provider (ISP). The connectivity of the Internet at the network level is due to the interaction between autonomous systems. As the number of alternative routes between ASs increases, fault tolerance arises and Internet stability in a given country increases. However, some paths become more important than others, and having as many alternative routes as possible is the only way to ensure system reliability (in the sense of AS).



The global connectivity of any AS, regardless of whether it represents a minor Internet provider or an international giant with millions of service consumers, depends on the quantity and quality of its paths to Tier-1 providers. As a rule, Tier-1 means an international company offering a global IP transit service and connecting to other Tier-1 operators. However, within this elite club there is no obligation to maintain such a connection. Only the market can give motivation to such companies to unconditionally connect with each other, providing high quality service. Is this a sufficient incentive? We will answer this question below in the section on IPv6 connectivity.



If your ISP loses touch with at least one of its own Tier-1 connections, it will most likely be unavailable in some parts of the Earth.

Internet Reliability Measurement

Imagine that AS is experiencing significant network degradation. We are looking for the answer to the following question: "What percentage of AS in this region can lose touch with Tier-1 operators, thereby losing global availability?"

IPv4 Reliability

Below you can see the top 20 countries in terms of reliability in terms of fault tolerance in the event of a failure of a single AS. In practice, this means that the country has good Internet connectivity, and the percentage reflects the share of AS, which will lose global connectivity in case of failure of the largest AS.



Brief facts:

• The United States dropped 11 positions from 7th to 18th place;
• Bangladesh came out of the top 20;
• Ukraine rose by 8 positions to 4 place;
• Austria flew out of the top 20;
• Two countries are returning to the top 20: Italy and Luxembourg after coming out in 2017 and 2018, respectively.

Every year, interesting movements take place in the sustainability rating. Last year, we wrote that the overall performance of the top 20 countries has not changed much since 2017. It is worth noting that, year after year, we note a positive global trend towards increased reliability and overall availability. To illustrate this point, we compare the average and median changes over 4 years in the overall IPv4 sustainability rating for all 233 countries.





The number of countries that managed to reduce their dependence on a single AS to less than 10% (which is a sign of high fault tolerance) increased by 5 compared to last year, and as of September 2019 reached 35 national segments.



Thus, as the most significant trend observed during the period of our study, we identify a significant increase in network resilience worldwide, both in IPv4 and IPv6.

IPv6 Failover

For several years, we reiterated that the erroneous assumption that IPv6 works just like IPv4 is the main structural problem in the process of developing and implementing IPv6.



Last year we wrote about peer-to-peer wars that persist not only in IPv6, but also in IPv4, where Cogent and Hurricane Electric do not interact with each other. This year, we were surprised to find that another pair of last year's rivals, Deutsche Telekom and Verizon US, successfully installed IPv6 peering in May 2019. You are unlikely to find any mention of this, but this step is huge - two large Tier-1 providers stopped the quarrel and, finally, established a peer-to-peer connection using the protocol, which we all wish for much more active development.



To ensure complete connectivity and highest reliability, routes to Tier-1 operators must be present at all times. We also calculated the percentage of ASs in a country that have only partial connectivity in IPv6 due to peer-to-peer wars. Here are the results:







After a year, IPv4 remains significantly more reliable than IPv6. The average reliability and stability of IPv4 in 2019 is 62.924%, and 54.53% for IPv6. IPv6 still has a high proportion of countries with poor global availability — that is, a high percentage of partial connectivity.



Compared to last year, we saw a significant improvement in three large countries, especially in terms of partial connectivity. Last year, Venezuela had 33%, China 65% and the UAE 25%. While Venezuela and China have significantly improved their own connections, solving serious problems of partially interconnected networks, the UAE remained without positive dynamics in this area.

Broadband and PTR Records

Repeating the question that we asked ourselves from last year: “Is it true that the leading provider in the country always affects regional reliability more than all the others or some other?”, We developed an additional metric for further study. Perhaps the most significant (in terms of customer base) Internet provider in this area will not necessarily be the autonomous system that will become most important in ensuring global connectivity.



Last year, we determined that the most accurate measure of the actual significance of a provider can be based on an analysis of PTR records. As a rule, they are used for reverse DNS lookups: using the IP address, you can identify the associated host name or domain name.



This means that PTR can allow the measurement of specific equipment in the address space of an individual operator. Since we already know the largest ASs for each country in the world, we could calculate the PTR records in the networks of these suppliers, determining their share among all the PTR records in the region. You should immediately make a disclaimer: we only calculated PTR records and did not calculate the ratio of IP addresses without PTR records to IP addresses with PTR records.



So, further we are talking exclusively about IP addresses with PTR entries present. Creating them is not a general rule, so some providers enter PTR, while others do not.



We showed how many of these IP addresses with the specified records PTR will be disconnected in case of disconnection from / together with the largest (according to PTR) autonomous system in the specified country. The figure reflects the percentage of all PTR-enabled IP addresses in the region.



Let's compare the 20 most reliable countries from the IPv4 rating in 2019 with the PTR rating:







Obviously, the approach considering PTR records gives completely different results. In most cases, not only the central AS in the region changes, but the percentage of instability for the indicated AS is completely different. In all the regions reliable from the point of view of global availability, the number of PTR-enabled IP addresses that will be disconnected due to the fall of AS is ten times higher.



This may mean that the leading national Internet service provider always owns end users. Thus, we must assume that this percentage is part of the ISP user and client base, which will be disabled (in case it is impossible to switch to an alternative provider) in the event of a failure. From this point of view, countries no longer seem as reliable as they look in terms of transit. We leave to the reader the possible conclusions from comparing the top 20 IPv4 with PTR rating values.

Detail changes in individual countries

As usual in this section, we start from the very special position of AS174 - Cogent. Last year, we identified its impact on Europe, where AS174 is rated critical for 5 of the top 20 countries in the IPv4 sustainability rating. This year, Cogent maintains a presence in the top 20 in terms of reliability, however, with some changes - in particular in Belgium and Spain, the AS174 has been replaced as the most critical AS. In 2019, for Belgium she became AS6848 - Telenet, and for Spain - AS12430 - Vodafone.



Now, let's take a closer look at two countries with historically good resiliency indicators that have made the most significant changes over the past year: Ukraine and the United States of America.



First, Ukraine dramatically improved its position in the IPv4 rating. For details, we turned to Max Tuliev, a member of the board of the Ukrainian Internet Association for details of what happened in his country over the past 12 months:

“The most significant change that we see in Ukraine is a drop in the cost of data transit. This allows most profitable Internet companies to acquire several superior connections outside our borders. Hurricane Electric is especially active in the market, offering “international transit” without a direct contract, because they do not remove prefixes from exchanges - they simply announce a customer cone at local traffic exchange points. ”

The main AS for Ukraine has changed from AS1299 Telia to AS3255 UARNET. Mr. Tuliev explained that, as a former educational network, now UARNET has become an active transit, especially in Western Ukraine.



Now we are transported to another part of the Earth - in the USA.

Our main question is quite simple - what are the details of the US stability decline by 11 positions?



In 2018, the United States took 7th place in the rating with 4.04% of the country, potentially losing global availability in the event of AS209 failure. Our 2018 report provides some insight into what has changed in the United States a year ago:

“But the big news is exactly what happened in the United States. For two consecutive years - 2016 and 2017 - we have identified AS174, Cogent, as decisive in this market. This is no longer the case - in 2018, AS 209 CenturyLink replaced it, sending the United States up three positions, to 7th place in the IPv4 rating. ”

The 2019 results show that the United States is ranked 18th with a sustainability score of 6.83% - a change of more than 2.5%, which is usually enough to drop the IPv4 sustainability rating from the top 20.



We contacted the founder of Hurricane Electric, Mike Leber, to get his comment on this situation:

“This is a natural change as the global Internet continues to grow. The IT infrastructure in each country is growing and modernizing to support the information economy, which is constantly changing and developing. Productivity improves customer service and revenue. Local IT infrastructure improves productivity. These are macroeconomic forces. ”

It is always interesting to analyze what is happening in the largest economy in the world, especially when we observe such a significant drop in the reliability rating. Recall - last year we celebrated the replacement of the AS174 Cogent with the AS209 CenturyLink in the United States. This year, CenturyLink lost ground as a country’s critical AS to another autonomous system - AS3356, owned by Level3. This is not surprising, since the two companies actually represent the same organization since the takeover of 2017. From now on, CenturyLink connectivity is completely dependent on Level3 connectivity. It can be concluded that the overall decrease in reliability is associated with an incident that occurred on the Level3 / CenturyLink network at the end of 2018, when 4 unidentified network packets interrupted the Internet for several hours, in a large territory of the United States. This event definitely affected the ability of CenturyLink / Level3 to provide transit to the largest players in the country, some of which could switch to other transit providers or simply diversify communication channels and higher-level connections. However, despite all of the above, Level3 remains the most important connectivity provider for the United States, disabling which could result in a lack of global availability for nearly 7% of local autonomous systems that rely on this transit.



Italy returned to the top 20 in 17th place with the same AS12874 Fastweb, which is probably the result of a significant improvement in the quality and number of routes to this provider. After all, in 2017, Italy fell to 21st place with him, leaving the top 20.



In 2019, Singapore, which entered the top 20 of the ranking only last year, but immediately to 5th place, again received a new critical ASN. Last year, we tried to explain the changes in the regions of Southeast Asia. This year, Singapore-critical AS has changed from last year's AS3758 SingNet to AS4657 Starnet. With this change, the region lost only one position, falling to 6th place in the rating in 2019.



China has made a significant leap from 113th place in 2018 to 78 in 2019, with a change of about 5% in the stability of IPv4 according to our methodology. In IPv6, China's partial connectivity dropped from 65.93% last year to just over 20% this year. The primary ASN in IPv6 changed from AS9808 China Mobile in 2018 to AS4134 in 2019. In IPv4, the AS4134 owned by China Telecom has been critical for many years.



In IPv6, however, the Chinese Internet segment fell 20 places in the 2019 sustainability rating - from 10% last year to 23.5% in 2019.



Probably, all this testifies to only one simple thing - China Telecom is actively improving its infrastructure, remaining the main communication network with external Internet for China.



With the growing risks of cybersecurity and, in fact, the constant flow of news about attacks on the Internet infrastructure, it is time for all governments, private and state-owned companies, but first of all for ordinary users to carefully evaluate their own positions. The risks associated with regional connectivity need to be studied carefully and honestly, analyzing the true levels of reliability. Even low values ​​in the instability rating can cause real problems with accessibility in the event of a massive attack on a large, national, provider of a critical service, for example, DNS. Do not forget also that the outside world will disconnect from services and data located within the region, in the event of a complete loss of connectivity.



Our study clearly shows that the markets of Internet providers and telecom providers based on competition ultimately develop more dynamically in order to become much more stable and resilient in relation to risks within and even outside a specific region. Without a competitive market, the failure of one AS can lead to a loss of network connectivity for a significant part of users from a country or a larger region.