Terrestrial Fibre Optic Network

China has eight major backbone networks, some of which were merged as a result of market reform in 2008. The resulting major commercial networks are:

• ChinaNet (China Telecom)

• UniNet (China Unicom)

• CMNet (China Mobile)

In addition, there are three academic and public sector networks:

• CERNET – China Education and Research Network (Ministry of Education)

• CSTNet – China Science and Technology Network (Chinese Academy of Sciences)

• CIETnet – China International Economic and Trade Network (Ministry of Foreign Trade and Economic Cooperation)

China Telecom’s ChinaNet is the country’s largest Internet Protocol (IP) network, providing access for all major Internet service providers nationwide through a 40 Gb/s Multiprotocol Label Switching (MPLS)-enabled IP backbone using synchronous digital hierarchy and dense wavelength division multiplexing technologies. Backed by service level agreements (SLAs), access is available via IP, asynchronous transfer mode and frame relay with speeds ranging from DS1 (1.5 Mb/s) to gigabit Ethernet. It offers public and private peering using the Border Gateway Protocol, flexible billing options (flat or usage-based), and real-time monitoring and reporting. A map from 2011 on the company’s website shows that the vast majority of its backbone fibre is installed underground, providing the best possible robustness against damage e.g. due to natural disasters.

China Unicom’s UniNet also covers all 31 provinces of the country, uses the same state-of-the-art technologies as ChinaNet, and offers many of the same features.

Figure 10: China Unicom's domestic MPLS Virtual Private Network

Source: China Unicom

The fibre optic backbone networks of the two main operators—China Telecom and China Unicom—show good geographic correlation with population density, and therefore also with areas of high natural disaster occurrence as per Figure 2. However, some neighbouring countries with similar or lower population densities have higher fibre densities, for example in Bangladesh, India and Viet Nam.

Figure 11: Terrestrial fibre optic backbone infrastructure in China and population density

Source: International Telecommunication Union

China also has a relatively low density of fibre nodes compared with most neighbouring countries, even in the more densely populated areas of China, as shown in Figure 12. In areas at greater distances from the nearest node, the effective transmission speed and quality of service may be compromised (see Section 5.2.1.1).

China’s relatively low fibre node density becomes apparent in the speed test results in Section 5.1.1.1, and as shown in Figure 13, the mean server distance in China (at 141 miles) was higher than in most other countries in 2014. Among ESCAP member countries, only the tests in Uzbekistan, Iran, Bhutan and Afghanistan saw greater server distances.

Figure 12: Terrestrial fibre optic backbone networks and nodes in China

Source: International Telecommunication Union

Figure 13: Mean server distance in speed tests as per Figure 3 and Figure 4, 2014

Source: Based on ESCAP, speedtest.net

5.2.1.1 Quality of Service

Besides speed (see Section 5.1.1.1 for fixed-line and Section 5.1.2.2 for mobile broadband access), latency and packet loss are the key performance indicators for data networks. Both are particularly important for real-time services such as VoIP and video streaming.

In terms of latency, China’s performance is average in the region, at around 100 milliseconds, but it does lag behind leading markets such as the Republic of Korea and Singapore (see

Figure 14). However, China is among the top three countries in the region in terms of latency reduction since 2010 (see Figure 15).

Figure 14: Network latency in selected ESCAP member countries, 2013

Source: Based on ESCAP, speedtest.net

Figure 15: Network latency in milliseconds and percentage change, 2010 – 2013

Source: ESCAP, speedtest.net

In terms of packet loss, China’s performance is also average in the region, at around 1.3 per cent, and it lags behind countries such as the Republic of Korea, Viet Nam, Malaysia, Indonesia and the Philippines (see Figure 16). However, China has shown the best performance in terms of packet loss reduction since 2010 (see Figure 17).

Figure 16: Packet loss in selected ESCAP member countries, 2013

Source: Based on ESCAP, speedtest.net

Figure 17: Packet loss in per cent and percentage change, 2010 – 2013

Source: ESCAP, speedtest.net

In summary, the quality of service on China’s telecom networks in terms of latency and packet loss is in line with regional averages, but the strong improvement in both key performance indicators in the past few years is testament to the fact that continued significant investment in network infrastructure is taking place that will see the country catch up with leading markets in the region.

5.2.1.2 Redundancy

Network redundancy is important for ensuring service availability and minimal downtimes, as expected from operators who guarantee certain performance parameters in SLAs. SLAs typically include a force majeure clause that relieves the operator from performance obligations in cases of extraordinary events or circumstances beyond its control, such as war, riots, strikes, crime, or natural disasters—in legal terms often referred to as ‘Acts of God’.

However, service reliability becomes most vital especially in disaster situations.

There are several levels of redundancy that can improve network and service reliability in disaster situations. China’s fibre optic backbone infrastructure is relatively well developed in this regard, but there are some areas of concern, which are outlined below.

Two of the country’s leading backbone network operators—China Telecom and China Unicom—claim to have fully meshed and fully redundant backbone networks. This means that every network node can communicate with any other node, and the backup of certain network components and databases are held in standby, ready to take over in case of any failures in the primary network. This is common practice for backbone network operators.

In terms of network topology, China’s fibre optic backbone infrastructure consists of many interconnected fibre rings. A ring structure is the best solution for creating redundancy because if a ring is broken, virtually all locations along it can still be reached by routing traffic in the other direction around the ring. The IP and other advanced routing mechanisms commonly used in modern telecom networks provide dynamic self-healing capabilities to these networks to minimize disruptions caused by local failures.

A total of 60 fibre rings can be identified on the map in Figure 18 (not including metropolitan fibre rings, which are not visible on the map). However, closer analysis reveals that a significant number of the fibre routes nationwide are operated by only one carrier (shown in red in Figure 18). The routes shown in brown contain cables operated by at least two different carriers, and the ones shown in green are those where a second cable is currently under construction.⁶ Some routes contain two cables operated by the same carrier; in these cases one of them is likely to be an older low-capacity cable.

Not shown in Figure 19 is China Mobile’s backbone network (which appears to be used for internal purposes only), and the non-commercial academic and public sector networks. In most cases, the single carrier operating the red fibre routes is China Telecom; China Unicom is the single carrier on only seven of them, most of which are relatively short. This means that the China Unicom network is more vulnerable to service disruptions. It also means that when a carrier experiences a catastrophic failure on one or several of the red routes, there would be no other carrier’s fibre infrastructure in place that could potentially take over at least some of the traffic load. Satellite and terrestrial microwave links (see Sections 5.2.2 and 5.2.3) can be used as a backup in such cases, but their coverage and/or capacity is limited.

China Unicom’s domestic backbone network map (see Figure 19) shows that the company does operate on more than seven of the red routes in Figure 18, and it also shows some additional ones. If both maps are correct, this most likely means that China Unicom is leasing capacity on some of China Telecom’s fibre routes, and the deployment of new routes is ongoing. Some of the additional routes may be microwave radio links.

6 Details can be examined at http://www.itu.int/itu-d/tnd-map-public/index.html.

Figure 18: Terrestrial fiber optic backbone infrastructure in China, single and multiple links

Source: International Telecommunication Union

Figure 19: China Unicom's domestic backbone network

Source: China Unicom

The central and western parts of China are most vulnerable to disruptions of fibre optic backbone connectivity due to a lack of redundancy since they are where some of the country’s worst earthquakes have occurred. Other vulnerable areas include the extreme northeast that is frequently affected by forest fires, some densely populated eastern and southern parts of the country, and the coastal areas where floods and tropical cyclones occur regularly.

5.2.1.3 Internet Interconnection Points

In a joint project, China’s three leading telecom carriers—China Telecom, China Unicom and China Mobile—completed the construction of seven new Internet interconnection points in 2014, including over 3,000 km of new fibre optic cable at a cost of USD 477 million. The additional interconnection points are mostly located inland in Chengdu, Xian, Wuhan, Shenyang, Nanjing, Chongqing and Zhengzhou. They will relieve traffic in the three existing interconnection points in Beijing, Shanghai and Guangzhou; increase average download and upload speeds; and provide better redundancy to protect against service disruptions, for example in disaster situations.