In-depth interpretation of the development of global submarine optical cables and the distribution of submarine cables in my country
Undersea communication 100 years earlier than the Internet
Let us turn the time back to the 1950s. At that time, the need for regular communication between different computer users and communication networks began to emerge, which also prompted research on decentralized networks, queuing theory, and packet switching. appeared one after another; subsequently, ARPAnet (ARPAnet Network) came out in the 1960s and expanded into the Internet in 1973; the following year, Robert Kahn of ARPA and Winden Zeff of Stanford proposed the TCP/IP protocol, which finally defined the transmission of messages between computer networks. The method of writing... This is the beginning of the great development of the Internet!
The history of the development of the global Internet can be traced back to the 1950s, so when did our country access the (international) Internet? In this regard, the time point that is more recognized by the industry is April 1994, when the 64K Internet channel between China and the world was opened (with the help of international satellite channel access), which is also considered a turning point in China's "going global".
However, it must be said that our communication with the world this time is only "narrowband" communication, and all we can do is allow hundreds of domestic scientists to "experience" sending and receiving emails. ..
So how is the Internet "broadband" communication we enjoy today achieved? The answer is submarine optical cables.
In fact, the so-called global Internet is composed of interconnected networks in countries around the world. Very large local area network, in which intercontinental connections rely on The main ones are satellite communications and submarine optical cables.
However, considering that satellite communication bandwidth is limited and expensive, more than 90% of the world’s international data is transmitted through submarine optical cables, which means that basically It is submarine optical cables that build today’s global “broadband” Internet!
Two major inventions of undersea communications, 100 years earlier than the Internet, led to two changes
When talking about undersea communication, its history is 100 years earlier than the Internet. However, at that time, undersea communication was still realized with the help of cables. In 1850, the Anglo-French Telegraph Company began to lay the world’s first cable between Britain and France. A submarine cable, which at that time could only send Morse telegraph code; but in 1866, the United Kingdom laid the entire transatlantic submarine cable between the United States and Britain (The Atlantic The successful laying of Cable enabled transatlantic telegraph communication between the European and American continents for the first time.
Subsequently, Bell invented the telephone in 1876, and people's dream of realizing global communication became stronger and faster. Construction of the Global Undersea Cable - The Global Undersea Communication Cable was completed in 1902
When talking about my country’s first submarine cable, It can be traced back to the Qing Dynasty. In order to realize cross-strait telegraph communication, Liu Mingchuan, the first governor of Taiwan at that time, began to lay waterway wires connecting the entire island of Taiwan and the mainland in 1886. It was completed in 1888. One of them was between Chuanshi Island in Fuzhou and Shanghai in Taiwan. The waterway wire between Tainan and Tainan (Taiwan) (177 nautical miles in total), and the other is the waterway wire from Anping, Tainan to Penghu (53 nautical miles in total)
Of course, human dreams are endless! In the 1950s, as the Internet began to emerge, people had higher requirements for the call quality and data transmission speed of undersea communications.
At this time, the world's first laser came out (1960), and people began to try to use lasers to transmit data information in optical fibers. Then in the 1970s and 1980s, the Internet had already emerged. began to emerge in developed countries around the world, and the shortcomings of submarine cables (bandwidth, poor transmission stability, etc.) have gradually become apparent. Therefore, optical fibers (i.e., submarine optical cables) with long transmission distance, large capacity, etc. have been placed in the High hopes!
In 1988, the first transoceanic submarine optical cable (TAT-8) system between the United States, Britain and France was built. The submarine optical cable is 6,700 kilometers long and contains 3 pairs of optical fibers. Each pair transmits The speed is as high as 280Mb/s, which is much faster than submarine cables. This also marks the official arrival of the submarine optical cable era.
The following year, the submarine optical cable across the Pacific Ocean (13,200 kilometers in length) was also successfully constructed. From then on, All intercontinental undersea communicationsCoaxial cables were replaced by optical cables; in the same year, our country also began to enter the era of submarine optical cables.
Distribution of global submarine optical cables and my country's submarine optical cables
Overview of global submarine optical cables
With the rapid development of the Internet, the construction of global Haidian optical cables is also accelerating. Currently, more than 230 submarine optical cables have been put into use around the world, connecting six continents except Antarctica; in addition, there are ten There are more than one submarine optical cable under construction; if you want to have a clear and comprehensive understanding of the distribution of global submarine optical cables, you can refer to the 2015 global submarine optical cable layout map provided by TeleGeography.
Overview of my country's submarine optical cables: 4 entrances and 8 optical cables
Our country began to invest in and build global submarine optical cables in 1989, and achieved the landing of the first international submarine optical cable in 1993 (C-J submarine optical cable system between China and Japan); subsequently in 1997, The global submarine optical cable system (FLAG) that my country participates in the construction of It was completed and put into operation. This was also the first intercontinental submarine optical cable to land in my country; and in 2000, with the opening of the Shanghai landing station of the Asia-Europe submarine optical cable, my country realized connections with 33 countries and regions in Asia and Europe. , also marks that my country's undersea communications have reached a new height.
So up to now, how many submarine optical cables have connected our country to the world? How many landing stations are there? The answer is 4 entrances (landing stations) and 8 submarine optical cables (excluding Hong Kong, Taiwan), here is a detailed introduction:
First of all, in terms of landing points, my country's landing stations are currently set up in four areas in three cities, namely Qingdao landing station in Shandong (affiliated to China Unicom), Chongming landing station in Shanghai (affiliated to China Telecom), and Nanhui landing station in Shanghai Station (affiliated to China Unicom) and Guangdong Shantou Login Station (affiliated to China Telecom)
In terms of submarine optical cables, we will first introduce it from the Asia-Pacific region:
Asia-Pacific Cable Network-2 (APCN2), with a total length of 19,000 kilometers, uses 4 pairs of fiber cores. Each pair of 64*10Gbps DWDM optical fiber technology has a design capacity of 2.56Tbps/s and mainly connects China, Japan, South Korea, Singapore, Malaysia and other regions. The landing stations in the mainland are Shanghai and Shantou.
East Asia Crossing/City-to-City Cable System and City-to-City Submarine Cable System (EAC/C2C), with a total length of 36,800 kilometers, using 4 pairs of fiber cores, each pair 64*10Gbps DWDM optical fiber technology (EAC) and 8 pairs of fiber cores, each pair 96*10Gbps DWDM optical fiber technology, with a design capacity of 2.56Tbps/s (EAC) and 7.68Tbps/s (C2C), mainly connects mainland China, Hong Kong, Japan, South Korea, Taiwan, Singapore and the Philippines. The landing stations in the mainland are Qingdao and Shanghai.
China-Japan Fiber Optic Submarine Cable System (C-J), with a total length of 1,300 kilometers, uses PDH System optical fiber technology, with an optical fiber capacity of 560Mbps. It is mainly used for international long-distance telephone services and digital circuit services between China and Japan. The landing station in the mainland is Shanghai.
South-East Asia Japan Cable System (SJC), Mainly connecting 8 countries and regions in Southeast Asia and Japan, with a total length of 10,700 kilometers, using 6 pairs of fiber cores, 64*40Gbps DWDM optical fiber technology, the optical fiber capacity is up to 15Tbps, and the landing station in mainland China is Shantou.
Let’s take a look at the submarine optical cables connecting Southeast Asia->Middle East->Europe and other regions. There are two: Fiber-Optic Link Around the Globe, FLAG), which is the world's first large-scale international submarine optical cable system that simultaneously connects Asia, the Middle East and Europe. It is 27,000 kilometers long and uses 2 pairs of fiber cores, each pair 5Gbps. DWDM optical fiber technology, optical fiber capacity up to 10Gbps, the landing station in mainland China is Shanghai
Asia-Europe submarine optical cable
Asia-Europe submarine optical cable (South-East Asia - Middle East - Western Europe 3, or SEA-ME-WE 3), is currently the world's most expensive, longest (39,000 kilometers) submarine optical cable that passes through the most countries and regions. It uses 2 pairs of fiber cores. Each pair of 48*10 Gbps DWDM optical fiber technology has an optical fiber capacity of 960Gbps. The landing stations in mainland China are Shanghai and Shantou.
Finally, let’s introduce the two submarine optical cables connecting North America:
American submarine optical cable
China-US submarine optical cable (China-US CN or CUCN), mainly connects Asia and North America, with a total length of 308,000 kilometers, using 4 pairs of fiber cores, each pair 8*2.488Gbps SDH over DWDM optical fiber technology, the optical fiber capacity is 80Gbps, and the landing stations in mainland China are Shanghai and Shantou.
China-US direct submarine optical cable (Trans-Pacific Express, or TPE) is the world's first submarine high-speed (trans-Pacific) direct optical fiber cable, with a total length of 26,000 kilometers and using 8 pairs Fiber core, 64*10Gbps DWDM fiber technology, fiber capacity is 5.12Tbps, of which the landing stations in mainland China are Shanghai and Qingdao
Although the quantity is small, the security is high< /p>
It is not difficult to see from the above introduction that my country (mainland region) has relatively fewer landing stations and submarine optical cables than developed countries in Europe and the United States, but the benefits it brings are obvious. ——Strengthen network security protection.
You must know that submarine optical cables will also bring network security threats, and only four landing stations are allowed to enter the country, which provides great convenience for security protection, that is, only four landing stations are allowed to enter the country. The security protection capabilities of these four "entrances" need to be strengthened to resist external network security threats
Not that simple: the design and laying of submarine optical cables
Design of submarine optical cable: anti-corrosion, anti-penetration, and anti-shark
Compared with coaxial cables, optical fibers have obvious advantages, but they themselves are quite fragile. Therefore, this places higher requirements on the peripheral protection structure of submarine optical cables that protects optical fibers.
Specifically, the design of submarine optical cables must ensure that the internal optical fibers are not affected by external forces and the environment. Its basic requirements include adapting to submarine pressure, being wear-resistant, not prone to corrosion, etc.; at the same time, it must also prevent the internal generation of hydrogen (So aluminum cannot be used) and external hydrogen intrusion (to prevent gas penetration); in addition, it must have a suitable armor layer to prevent damage from fishing trawls, anchors and sharks
When the optical cable breaks. , it is also necessary to reduce the length of seawater penetrating into the optical cable as much as possible; at the same time, it can withstand the tension during laying and recycling; finally and most importantly, the service life of submarine optical cables is generally required to be more than 25 years.
Based on the above requirements, the current design structure of submarine optical cables usually spirally wraps the optical fiber that has been coated once or twice in the center, and then wraps the reinforcing member (made of steel wire) around it (diameter usually 6 9 mm).
Specifically includes: polyethylene layer, polyester resin or asphalt layer, steel strand layer, aluminum waterproof layer, polycarbonate layer, copper pipe or aluminum pipe, paraffin wax , alkane layer, optical fiber bundle, etc.
Padding process: from relying on trends to relying on robots
The laying project of submarine optical cable is recognized by countries around the world as one of the most complex and difficult large-scale projects. This is It is not difficult to understand why the life span of submarine optical cables is required to be more than 25 years, because it is very troublesome to lay it once! Here is a detailed introduction to the laying process of submarine optical cables:
The laying process of submarine optical cable can be divided into two Parts include laying in shallow sea areas and laying in deep sea areas. In the deep sea areas, there are three stages: surveying and cleaning, submarine cable laying and burial protection.
The completion of the laying of submarine optical cables mainly relies on the Optical cable laying ships and underwater robots. Among them, optical cable laying ships must pay special attention to the sailing speed and cable release speed to control the water entry angle of the optical cable and the laying tension to avoid damage to the fragile optical fibers in the optical cable due to too small a bending radius or excessive tension.
A submarine optical cable laying process. In the shallow sea area, the laying ship stays several kilometers away from the coast. It is towed by the shore tractor and placed on the floating cable. The optical cable on the package is pulled to the shore, and then the floating package is removed to sink the optical cable to the seabed; in the deep sea area, the laying ship is mainly responsible for releasing the optical cable, and then the underwater detector is used with the underwater remote control vehicle to conduct underwater monitoring and adjustment , to avoid uneven and rocky places on the seabed.
Then, the underwater robot began to perform three steps of work: the first step, use.High-pressure water flushing creates a trench about 2 meters deep on the seafloor; the second step is to put the optical cable into the trench; the third step is to cover it with the help of sand and soil next to it.
What needs to be noted here is that it is difficult to lay an intercontinental submarine optical cable at one time, because the most advanced optical cable laying ship can only carry 2,000 kilometers. Long optical cables (and the current laying speed can only reach 200 kilometers/day), so the laying must be carried out in sections, and the "optical cable docking" of each section needs to be completed on the laying ship, and requires extremely high technology.
Submarine optical cable repair: more difficult than laying!
In fact, since its birth, submarine communications have faced various threats and challenges. Once submarine cables (including electric cables and optical cables) are damaged, communications will be interrupted, and the impact will be huge. It goes without saying.
As for the interruption of submarine cables, in the 1970s and 1980s, they were extremely vulnerable to fishing boats (towedNets), damage to anchors, and even bites from sharks.
Fortunately, with the improvement of relevant regulations (forbidding anchoring of ships in areas above submarine cables) and the improvement of submarine cable protection capabilities, these cases of damage to submarine cables have begun to decrease significantly.
However, there is another situation that is unavoidable in damaging submarine cables, and that is earthquakes.
For example, the strong earthquake that occurred in Taiwan in 2006 caused damage or even interruption of many international submarine optical cables, causing domestic Internet users to be unable to access foreign websites normally; similarly, the 2011 earthquake in Japan The strong earthquake also caused domestic users to be unable to log in to U.S. websites.
So, damage to submarine optical cables is inevitable, so repairing submarine optical cables has become an essential task.
When it comes to the repair of submarine optical cables, it is even more difficult than the laying process.
Shallow sea areas can also be explored and simply repaired manually. However, trying to find problematic optical cables with a diameter of less than 10 centimeters from the seabed hundreds of meters or even thousands of meters deep is like looking for a needle in a haystack. .
Fortunately, with the development of positioning technology, this repair process has begun to become efficient.
Let’s talk about the repair process of submarine optical cables in detail, which can be roughly divided into the following five steps:
The first step is to use a spread spectrum time domain reflectometer to locate the approximate fault location, and then use an underwater robot to scan and detect the location of the damaged submarine optical cable.Precise position;
In the second step, the robot digs out the optical cable buried under the sea, then cuts it with cable scissors and pulls it out of the water; at the same time, the robot will also cut it Place a wireless signal transceiver everywhere to prepare for subsequent repair of the connection;
The third step is to pull the other end of the optical cable out of the water through the positioning provided by the wireless signal transceiver.
Then use the instruments on the ship to connect both ends of the optical cable, and communicate with the nearest landing station to detect which end of the optical cable is blocked, and then cut off the damaged part;
The fourth step is to use a new optical cable to connect the two previous breakpoints, and the entire docking process has extremely high technical requirements;
Step 5, new After the submarine optical cable connection is completed, it needs to be repeatedly tested to ensure that communication and data transmission are normal.
Then, let the submarine optical cable be put into the water, and then complete the laying process of the submarine optical cable again.
Look at the future development and innovative value of submarine optical cables
Ushering in a new round of construction boom
With the Internet, especially With the rise of mobile Internet, global Internet data consumption has experienced explosive growth in the past 10 years.
Internet traffic reached 5GB per capita in 2013, and it is expected that this number will increase to 14GB by 2018.
This growth will undoubtedly bring about capacity problems, so building or upgrading submarine optical cables will be the general trend.
Google was the first to act. In August last year, Google announced the construction of the "FASTER" trans-Pacific high-speed Internet optical cable, which will use 6 pairs of optical cables and optical fiber technology to connect the United States and Japan, and the initial design bandwidth will be as high as 60Tbps (100Gb/s * 100 wavelength * 6 pairs of optical fibers) - 4 times the bandwidth of the previous SJC submarine optical cable, expected to be put into operation in the second quarter of 2016operations.
In April this year, operators from mainland China, Taiwan, South Korea, Japan and the United States jointly launched the New Cross Pacific International Submarine Cable (New Cross Pacific, Referred to as NCP) project construction.
It is understood that the submarine optical cable has a total length of more than 13,000 kilometers. By using the most advanced 100G wavelength division multiplexing transmission technology, the design capacity exceeds 80Tbps (20Tbps faster than Google FASTER).
It is expected to be put into operation in the fourth quarter of 2017. By then, it will become the submarine optical cable with the largest transmission capacity and the most advanced technology between Asia and North America, and can provide users with better and more reliable communication services. .
Submarine cable will enter the era of integration, not just transmission and communication
Currently, the vast majority of submarine cables and optical cables in the world are laid independently of each other, but in the near future, with the comprehensive development of offshore wind power generation, offshore oil platforms and other offshore operating systems, it has become an inevitable trend for a submarine cable to achieve power transmission and remote control at the same time. Therefore, submarine cables and optical cables will also inevitably move towards integration, that is, to create submarine photoelectric composite cables.
Of course, the important tasks shouldered by submarine cables in the future are not just communication and data transmission, because in the Internet of Things In the era, it can also carry sensors and dive into the deep sea. When an earthquake occurs on the seabed (which will trigger a tsunami), big data analysis can be performed on the seabed data collected by many sensors on the submarine cable. This can not only detect the tsunami pressure, but also predict the tsunami in advance. Assess potential threats and issue warnings to help coastal areas or relevant governments take preventive measures
Communications need multi-dimensional development to win the future
Although submarine optical cables have become the backbone of building the global "broadband" Internet, the security of submarine optical cables is not enough for governments and military agencies. For example, the famous "Ivy Bell" operation during the Cold War between the United States and the Soviet Union was "Monitoring" was achieved using submarine optical cables, and today, eavesdropping on submarine optical cables has even become a "standard operation" for intelligence agencies.
Also pay attention to What's more, it doesn't take a cyber war to paralyze a country's Internet. It only requires an underwater breathing apparatus and a pair of submarine cable scissors.
This kind of thing seems a bit fanciful, but in fact it was in 2013. In Egypt, artificial destruction of submarine optical cables occurred (wearing a diving suitCutting off submarine optical cables), causing Egypt's Internet speed to drop by 60% instantly.
To sum up, if we want to occupy a dominant position in the future global Internet, it is not enough to just build submarine optical cables. Only by realizing the multi-dimensional development of communications, For example, by trying to build aerial networks and accelerating the development of satellite communications, we can truly win the future!
