ODN network is a large fiber optic network, and building an ODN network is both difficult and expensive. The investment in ODN network construction can account for about 60% of network construction costs, indicating the importance of ODN network construction. However, even though the construction of ODN is costly, it is difficult to manage it. ODN mostly adopts a topology structure with many more connection points than a simple copper wire structure, making it challenging to manage, and the optical fiber is sensitive and easily damaged. Therefore, it is essential to pay attention to the construction and maintenance of ODN and to develop a targeted secure and reliable operation and maintenance system for the ODN network, ensuring safe and effective operation of ODN and rapid and accurate troubleshooting in case of failure.

Overview of ODN

ODN refers to the analog optical fiber node in the fiber-to-the-home (FTTH) network, which is the optical distribution node. Its main function is to connect the analog optical fiber and provide a channel for optical transmission. ODN consists of four subsystems: feeder fiber cable, distribution fiber cable, drop fiber cable, and optical fiber terminal. In the FTTH network construction, ODN serves as a bridge between the OLT and ONT. The components of ODN include optical fiber cable, optical splitter, optical connector, installation connection, etc.

ODN Network Structure

First-level Splitting Structure

The first-level splitting structure of ODN is to install the splitter in the optical cross connection cabinet or optical distribution box of the equipment room, community, and building. However, the advantages and disadvantages are different. The main advantages and disadvantages are as follows:

(1) If the splitter is placed in the equipment room, the advantage is that the splitter can be in a superior environmental condition, and the utilization rate of the PON port can be greatly increased. The disadvantage is that the occupancy of pipeline resources is not ideal, and the investment cost is also high.

(2) If the splitter is placed in the community’s optical distribution box, the advantage is that the PON port can be fully utilized, and the occupancy of the port resources can be greatly reduced, thereby reducing the investment cost of optical cable. The disadvantage is that the ability to connect the optical distribution box to users is greatly reduced.

(3) If the splitter is placed in the building’s optical distribution box, the advantage is to reduce the occupancy of optical cable and pipe resources. The disadvantage is that the utilization rate of PON port will be reduced when the user density is sparse, and there are fewer users accessing the network.

Second-level Splitting Structure

In the initial construction phase, when the number of users accessing the network is relatively small, ODN usually uses a first-level splitting structure. However, as the demand for user access increases, the first-level splitting structure can no longer meet the users’ needs. If the previous first-level splitting structure is still used, the utilization of PON ports will not be sufficient. To solve this problem, the second-level splitting structure was introduced. The second-level splitting structure refers to the setting of a first-level optical splitter in the community’s optical distribution box and a second-level optical splitter in the building’s splitter box. Through these two splitters, more users can access the network, and the utilization rate of the PON port is high.

Construction Strategy

The construction strategy of ODN is to cover the target area with a network system and address the positioning of the splitter and optical router to ensure the safe and efficient use of the network by users under the premise of economic development. The first-level splitter has the advantages of convenient construction and maintenance and is widely used. However, as the network industry matures and the price of network equipment gradually decreases, the construction cost will increase. Only by collecting user cables, the total cost of the cables can be controlled at a low level. Therefore, the advantages of second-level splitter construction gradually emerge in this situation. The basic ideas for network construction are as follows:

(1) For multi-layer, low-rise, and high-rise residential areas, if the volume ratio of the residential area is high and the network is newly built, a full coverage first-level splitter should be selected. If the volume ratio of the residential area is low, a full coverage second-level splitter should be selected. If it is a network renovation or secondary coverage network, a thin coverage second-level splitter should be used.

(2) For villas, whether it is a new network or a renovated network, a full coverage first-level splitter should be used.

(3) For the construction of new rural areas, both new and renovated networks should adopt a full coverage first-level splitter.

Network Management

ELD information is collected in intelligent devices and uploaded to the management system through portable terminals. This management system is highly intelligent and can organize and analyze ELD information to establish a fiber routing relationship system. When it is necessary to adjust fiber resources, the construction work order will be sent from the fiber resource management system through the intelligent management system to the portable terminal. After receiving the feedback information, the relevant construction personnel can carry out construction according to the work order. After the construction is completed, the construction result will be recorded and saved in the portable terminal and uploaded to the intelligent management system.

Network Applications

 ODN technology improves the stability of fiber networks

After the construction of urban networks, the quality of cables may gradually decrease due to various factors. Therefore, in order to avoid faults during future use, the lines should be fully tested before construction and regularly maintained afterwards to save labor and material costs. Therefore, single boards with idle fiber cores can be added to the city to detect the optical power, and external optical paths can also be tested. The results can be sent to the ODN network management system. Relevant personnel can perform a comprehensive analysis of the lines based on the feedback results, identify possible problems, and handle them in a timely manner to ensure that the fiber network can operate safely and normally. ODN technology realizes control over the urban area, reduces design costs, and greatly improves work efficiency. ODN technology can also identify the specific condition of external optical paths. Once a fault occurs, it can be immediately sent to the network management system. The network management personnel can perform a specific analysis of the situation, locate the fault, and send it to the repair department, reducing the time for additional inspections and making the maintenance work of the urban network more systematic.

ODN Technology Improves Scheduling Efficiency

Business scheduling is particularly important in the operation and maintenance of systems, and there are many requirements for the relevant personnel, namely, they must be proficient in scheduling skills and data accuracy. However, due to the differences in operating processes in various regions, ODN technology has gradually replaced manual scheduling, realizing scheduling using electronic information, greatly improving the efficiency of scheduling, and thereby minimizing operating and maintenance costs. When opening a common business, the system can use database statistics of resource data usage and select appropriate fiber optic cable scheduling. By using electronic processing, the efficiency of business scheduling can be improved and human errors can be reduced. Once an error occurs in a certain link, ODN can be used for quick calculation to generate a backup optical path for business switching. Maintenance workers can also use backup routing to improve scheduling efficiency while ensuring that business does not affect work.

ODN Technology Improves Network Management System

ODN system management is an automated and refined management of network ODN devices. ODN end devices refer to fiber optic cable distribution, which is often installed in pipeline wells in order to complete optical link operations. For example, during the process of the FAT connecting to the ONT device, the operator needs to complete the construction and management of the fiber optic cable, making it difficult to ensure the accuracy of information. Therefore, it can be concluded that the most important part of ODN system management is monitoring the end nodes.

 Applying Intelligent ODN Optical Distribution Network Technology to Improve Optical Network Investment Efficiency

With the continuous development of FTTH network construction, ODN has gradually become the main body of network construction investment. As people’s demand for networks continues to grow, the number of fiber optics has also increased sharply, and the number of fiber optic distribution has also increased significantly, but the locations are not centralized. There are optical equipment in every corner, making it difficult to find fiber optics. Therefore, attention must be paid to resource maintenance to reduce the likelihood of similar situations and ensure a good network environment.

Conclusion

ODN network is the foundation and most important part of FTTH network construction. Relevant units are also persevering in improving ODN technology to solve problems such as difficult construction and high costs. We should follow the principles of simple operation, excellent products, and intelligent management, gradually explore and build a low-cost and easy-to-manage ODN network. Starting from the fundamentals, we should try our best to solve the problems in ODN technology and provide customers with the best ODN equipment.

ELD: Electronic Logging Device (transportation hardware)