While the new infrastructure is accelerating the deployment of 5G networks, it is also pushing the backbone network of operators into the era of single-wavelength 200G. The backbone network is the "new infrastructure" in the new infrastructure.

It is understood that China Mobile recently announced the list of candidates for the centralized procurement of transmission equipment for the 13th phase of the new construction project of its inter-provincial backbone transmission network. Huawei Technologies Co., Ltd. and ZTE Corporation won the bid for the centralized procurement of WDM/OTN equipment boards and ports for the eastern and western regional planes respectively.

It is worth noting that this is the first time that China Mobile has centralized procurement of 200G OTN systems at the provincial backbone network transmission level. It is also the first operator among the three major domestic operators to centralized procurement of this system. If the progress goes smoothly, it will also be the first single-wavelength 200G backbone network in China after completion.

Although in 2019, China Telecom and China Unicom only conducted centralized procurement of 100G WDM/OTN equipment and continued to expand the capacity of their single-wavelength 100G all-optical networks, the two operators have conducted related tests on single-wavelength 200G and 400G backbone networks very early, and even conducted a small amount of centralized procurement. As the deployment of 5G networks accelerates, it is expected that the two operators will soon include the ultra-100G backbone network OTN system in the centralized procurement plan.

This means that the backbone network of operators and the commercial use of 5G networks will enter the single-wave 200G era simultaneously.

Why build a new 200G backbone network?

The main reason for building a new single-wave 200G backbone network is that the bandwidth of the existing backbone network is difficult to meet the actual needs after the large-scale commercial use of 5G in the future.

The three major operators have built a single-wave 100G backbone network and have carried out several rounds of capacity expansion to meet the growing traffic demand.

According to data from the Ministry of Industry and Information Technology, in 2019, mobile Internet access traffic consumption reached 122 billion GB, an increase of 71.6% over the previous year. As of the end of December last year, the number of Internet broadband access ports reached 916 million, of which fiber access (FTTH/0) ports reached 836 million.

At present, the country is promoting the construction of new infrastructure, and 5G is one of the seven major areas of new infrastructure. The substantial increase in bandwidth demand, network flattening, and interconnection between large central computer rooms and data centers in the 5G era will pose huge challenges to the backbone network. Some experts believe that the current single-wavelength 100G backbone network is difficult to meet the network bandwidth demand after 5G commercialization matures.

Wei Leping, executive deputy director of the Communications Technology Committee of the Ministry of Industry and Information Technology and director of the Technology Committee of China Telecom Group, predicts that China's backbone network capacity will exceed 1Pbps in 2020 and is expected to be close to 1.4Pbps in 2022.

The expansion of the backbone network is not like turning on and using the light, which requires operators to plan and build in advance, so China Mobile launched this 200G OTN backbone network centralized procurement in early 2020.

It is worth noting that some experts pointed out that the backbone network is evolving towards 400G and 600G, and it is expected that 1T equipment will mature in 2021.

This is indeed the case. It is reported that since 2016, China Unicom, China Mobile and China Telecom have successively launched single-wave 400G system tests. Among them, China Unicom also launched the centralized procurement of G.654.E optical fiber cables suitable for 400G systems in 2018. This means that the 400G era will not be far away.

What are the backbone network industry chain companies?

Although OTN technology is now mainstream in the backbone network, it is not only OTN manufacturers that participate in the construction of the backbone network.

It is understood that China's Internet architecture mainly adopts a hierarchical convergence method, which is vertically divided into three levels: backbone network, metropolitan area network and access network. Among them, the backbone network is the top-level inter-provincial high-speed network. Basic telecommunications operators set up backbone nodes in provincial capitals and major cities, and set up direct links between nodes to jointly form the backbone network.

After years of construction and development, there are currently seven backbone networks in the country, of which four are built and managed by the three major operators, namely China Telecom's CHINANET 163 and CN2, China Mobile's CMNET and China Unicom's China169.

The backbone network architectures of the three major operators are similar, mainly setting up the core layer (core nodes) and the regional layer (aggregation nodes, access nodes). The function of the core layer is mainly to provide interconnection with the international Internet and provide a channel for information exchange between regions. The regional layer mainly provides information exchange within the region and access to the backbone network for access networks. Communication between regions must pass through the core layer.

However, in recent years, operators have been promoting the evolution of the backbone network architecture towards flattening, increasing the number of core nodes, reducing the number of access nodes, allowing more large urban metropolitan area networks to directly access the backbone network, reducing routing nodes, and making information transmission simpler and more efficient.

Whether it is a core node or an access node, several routers and switches will be set up. These nodes are interconnected through OTN equipment and all-optical networks, and use BGP, IS-IS and other protocols for information transmission.

Through the analysis of the centralized procurement and bidding of operators in recent years, the main network elements for building a backbone network are OTN equipment, routers, switches, optical fiber cables, etc. Other network elements include DRA equipment, optical protection systems, quality monitoring systems, network management systems, security protection systems, as well as engineering design, engineering construction, and engineering supervision services.

In summary, the main OTN equipment manufacturers are Huawei, ZTE, Fiberhome Communications, and Shanghai Nokia Bell. The core router supplier is Huawei, and the high-end router suppliers are Huawei, ZTE, H3C, etc. The high-end switch suppliers are Huawei, Ruijie Networks, etc. The main fiber and cable suppliers are Changfei Optical Fiber, Fiberhome Communications, Hengtong Optics, Zhongtian Technology, Hangzhou Futong, Tongding Interconnect, etc. The optical device suppliers are Accelink Technologies, Bannard Communications, Jiexin Technology, etc. The DRA equipment suppliers are mainly Huawei and ZTE. The suppliers of OLP equipment, optical line protection boards, dispersion compensation units, optical amplifiers, cables, and optical attenuators are Accelink Technologies, Bannard Communications, Jiexin Technology, etc. The DDOS protection equipment suppliers are Huawei, Hangzhou Deep, Beijing Shenzhou Green Alliance, etc. In addition, there are a large number of backbone network engineering design, construction, and supervision service providers.

How far is the evolution to 400G?

The industry has always called for the construction of 400G backbone networks, and it has been predicted that this demand will appear around 2020, but it has not been realized due to cost reasons. Now China Mobile plans to build a new 200G backbone network, but it has also reserved space for the evolution to 400G in centralized procurement. It is reported that Huawei and ZTE's related products and solutions support 200G, 400G, and 1T transmission rates.

The biggest obstacle to the evolution to super 100G is the transmission distance without relays. In the context of generally compressing capital expenditures, operators hope to increase the optical transmission rate while ensuring a longer transmission distance and reduce the deployment of electrical relay sites to reduce the construction cost of the backbone network. Huawei said that its OTN products are based on the industry-leading Super 200G technology, which can achieve up to 5,000 kilometers of transmission without electrical relays; ZTE supports 1,700 kilometers of transmission without electrical relays.

In addition to Huawei and ZTE, FiberHome and Shanghai Nokia Bell have previously won the bid for the centralized procurement of 100G backbone network related projects of the three major operators, but failed to be selected for the centralized procurement of China Mobile's new 200G backbone network, which seems to mean that there is still a lot of room for the technical reserves of the industry chain to evolve towards super 100G.

It is worth noting that China Mobile only purchased WDM/OTN equipment boards and ports this time, but building a 200G backbone network requires not only OTN equipment, but also routers, switches and other network elements, especially optical fiber cables.

The general life of optical fiber is 20 years. In order to meet the needs of 5G networks, operators must consider the network needs of the next 10 to 20 years when purchasing optical fiber cables. The focus of future network needs is 400G, or even 1T speed, which means that operators need to deploy optical fiber and cable products that support 200G and 400G systems in advance, such as G.654.E optical fiber.

It is understood that the total length of China Mobile's new backbone network is 105,900 kilometers. If a backbone network cable is calculated as 48 cores, the number of optical fibers required to lay one optical cable this time is 5.0832 million core kilometers, but the actual purchase volume may be more than this number.

Although the new backbone network cannot use all G.654.E optical fibers for cost considerations, most of the time it is a hybrid cable of G.652.D and G.654.E optical fibers, but the upcoming demand will also be a big order for optical fiber and cable manufacturers. After all, the total demand for backbone networks is not high. Previously, the G.654.E optical fiber procurement volume in the Hebei Mobile provincial backbone transmission network core-added ultra-low loss G.654E optical cable framework project was only about 27,000 core kilometers; China Unicom conducted a second bidding for five provincial optical cable line construction projects such as the Hunan section of the Beijing-Hankou-Guangzhou optical cable, and the demand for G.654.E optical cables and hybrid cables was only about 2,971 kilometers.

Currently, the manufacturers that can supply G.654.E optical fiber mainly include Changfei Optical Fiber, Hengtong Optics, FiberHome Communications, Hangzhou Futong and other giants. In fact, not only optical fiber and cable manufacturers, but also optical devices, routers, switches, and other network element manufacturers will benefit from the construction of 200G backbone network.

The construction of single-wavelength 200G backbone network is imminent. This is an important step in the large-scale deployment of 5G. It is also a necessary upgrade of operators' fixed optical networks before the large-scale commercial use of 5G in the future, but it is not the end. Because with the gradual increase of 5G applications, after the Internet of Everything becomes possible, the evolution to 400G will be the inevitable choice for the backbone network. Considering that the time point when the backbone networks of the three major operators completed the evolution to 100G is only 5 to 6 years away, and now they are starting the construction of 200G backbone network, it means that the 400G era may not be far away under the promotion of new infrastructure.