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Fiber optic access network refers to the application form that uses fiber optic as the main transmission medium in the access network to achieve user information transmission. It is not a traditional fiber optic transmission system, but a special fiber optic transmission network designed for the access network environment.   Connected to service nodes through optical line terminals (OLTs) and to users through optical network units (ONUs). The fiber optic access network includes remote equipment optical network units and central equipment optical line terminals, which are connected through transmission equipment. The main components of the system are OLT and remote ONU. They complete the conversion of signaling protocols from the Service Node Interface (SNI) to the User Network Interface (UNI) throughout the entire access network. The access device itself also has networking capabilities and can form various forms of network topologies. At the same time, the access device also has local maintenance and remote centralized monitoring functions, forming a maintenance and management network through transparent optical transmission, and being included in the unified management of the network management center through corresponding network management protocols.   The role of OLT is to provide an interface between the access network and the local switch, and to communicate with the optical network units at the user end through optical transmission. It completely separates the switching function of the switch from user access. The optical line terminal provides maintenance and monitoring for itself and the user end. It can be placed directly with the local switch at the exchange end or set up remotely.   The role of ONU is to provide a user side interface for the access network. It can connect to multiple user terminals and has photoelectric conversion function as well as corresponding maintenance and monitoring functions. The main function of ONU is to terminate the optical fiber from OLT, process optical signals, and provide business interfaces for multiple small businesses, business users, and residential users. The network end of ONU is an optical interface, while its user end is an electrical interface. Therefore, ONU has optical/electrical and electrical/optical conversion functions. It also has the functions of digital to analog and analog-to-digital conversion for dialogue sounds. ONU is usually placed closer to the user, and its location has great flexibility.     Fiber Aceess Network classification Fiber access networks (hereafter FAT) are divided into two categories based on system allocation: active optical networks (AON) and passive optical networks (PON). As Yingda focus on passive fiber optic products, the following text will focus on introducing passive optical networks.   Active optical networks can be divided into SDH based AON and PDH based AON. The central equipment (CE) and remote equipment (RE) of active optical networks are connected through active optical transmission equipment, and the transmission technology is SDH and PDH technology that have been widely used in backbone networks, but SDH technology is the main one.   Passive Optical Network (PON) mainly refers to an Optical Distribution Network (ODN) between OLT and ONU, without any active electronic devices. It includes ATM based Passive Optical Network (APON) and IP based PON.   Passive Optical Network (PON) is a pure dielectric network that avoids electromagnetic interference and lightning effects from external devices, reduces the failure rate of lines and external devices, improves system reliability, and saves maintenance costs. It is a technology that telecommunications maintenance departments have long been looking forward to.   The specific advantages of passive optical access networks are as follows:   (1) Passive optical networks have small size, simple equipment, low installation and maintenance costs, and relatively small investment. (2) Passive optical devices have flexible networking and can support network topologies such as tree, star, bus, hybrid, and redundant. (3) Easy to install, it comes in both indoor and outdoor versions. Its outdoor appearance can be directly hung on the wall or placed on the "H" pole, without the need to rent or build a computer room. Active systems require photoelectric and electro-optical conversion, with high equipment manufacturing costs and the need for dedicated sites and computer rooms. Remote power supply issues are difficult to solve, and daily maintenance workload is heavy. (4) Passive optical networks are suitable for point to multipoint communication, using only passive splitters to allocate optical power. (5) Passive optical networks are pure dielectric networks that completely avoid electromagnetic interference and lightning effects, making them highly suitable for use in areas with harsh natural conditions. (6) From a technological development perspective, the expansion of passive optical networks is relatively simple and does not involve equipment modification. It only requires equipment software upgrades, one-time purchase of hardware equipment, and long-term use, laying the foundation for fiber to the home and ensuring user investment.   Fiber Access Netowrk Features The main characteristics of fiber optic access network are: 1、 The network coverage radius is generally small and does not require repeaters. However, due to the sharing of optical fibers by many users, the allocation of optical power or wavelength may require the use of fiber amplifiers for power compensation; 2、 Require the transmission of various broadband services, with good transmission quality and high reliability; 3、 The application scope of fiber optic access network is broad; 4、 The investment cost is high, network management is complex, and remote power supply is difficult. [2]   Fiber Access Methods According to the location of the Optical Network Unit (ONU), fiber access methods can be below types: FTTB (Fiber to the Building); FTTC (Fiber to the curb); FTTH (Fiber to the home); FTTO (Fiber to the Office); FTTF (Fiber to the Floor); FTTP (Fiber to the Premise); FTTN (Fiber to the Nodes); FTTD (Fiber to the Desktop); FTTR (Fiber to the room). Figure 1:Most popular fiber access methods   The most important forms are FTTB (Fiber to Building), FTTC (Fiber to Roadside), and FTTH (Fiber to User). FTTC mainly provides services for residential users, with optical network units (ONUs) located on the roadside, near the user's residence. The electrical signals from the ONUs are then transmitted to various users, usually using coaxial cables to transmit video services and twisted pair cables to transmit telephone services.   The ONU of FTTB is installed at the distribution box inside the building, mainly used for comprehensive buildings, remote medical care, remote education, and large entertainment venues, serving large and medium-sized enterprises, institutions, and commercial users, providing high-speed data, e-commerce, video and text services, and other broadband services.   FTTH is the placement of ONUs in user residences to provide various comprehensive broadband services for home users. FTTH is the ultimate goal of fiber optic access networks, but each user requires a pair of fibers and dedicated ONUs, making it expensive and difficult to implement.   Main features FTTCab FTTC FTTB FTTH FTTP ONU location Cross cabinet Roadside(Curb) Building residents' home companies, offices Type of Access Medium   Backbone:fiber optic; End:metal wire/wireless Backbone:fiber optic; End:metal wire/wireless Backbone:fiber optic; End:metal wire/wireless Full line fiber optic Full line fiber optic Reference wiring distance between optical nodes and user devices 1000m ~2000m 1000m ~2000m 1000m ~2000m A few meters to tens of meters A few meters to tens of meters User access speed Downstream maximum 25Mbit/s, upstream maximum 1.8Mbit/s Downstream maximum 155Mbit/s Downstream maximum 100Mbit/s The maximum up and down speed can exceed 100Mbit/s The maximum up and down speed can exceed 100Mbit/s Table 1: FTTx Structure Main Features   From the figure, it can be seen that FTTH is all connected to terminals through fiber optic networks, and the terminals connected to them are called Optical Network Terminals (ONTs). FTTB or FTTC is connected to buildings or curbstones through fiber optic networks, and then connected to terminals through copper twisted pair networks or wireless connections. The end devices of the fiber optic network are called optical network units (ONUs), which are connected to network terminals (NTs) through copper twisted pair networks or wireless connections. FTTCab is similar to FTTC, except that its ONU is located in a telecommunications cabinet.   The FTTB, FTTC, and FTTCab in the figure all belong to "partial" fiber to the home, which means that the fiber is not directly connected to the end user, but reaches near the end user and then connects to the end user through a twisted pair network. In FTTCab, the ONU in the telecom junction box is usually located 1000-2000m away from the end users, and in this case, one ONU unit can support about 500 end users. In FTTC, the ONU is closer to the end users, at 200-1000m, and can support 8-32 end users. The network between OLT and ONT/ONU is called Optical Distribution Network (ODN), and its distance can reach up to 20km, as shown in the figure.   Fiber Access Network Advantages: Compared with other access technologies, fiber access networks have the following advantages:   (1) Fiber optic access networks can meet users' needs for various services. People's demand for communication services is increasing. In addition to making phone calls and watching TV, they also hope for high-speed computer communication, home shopping, home banking, remote teaching, video on demand (VOD), and high-definition television (HDTV). It is difficult to achieve these businesses using copper wire or twisted pair cables.   (2) Fiber optics can overcome some limiting factors that copper cables cannot overcome. Fiber optic loss is low and the frequency band is wide, which eliminates the limitation of small copper wire diameter. In addition, optical fibers are not affected by electromagnetic interference, ensuring signal transmission quality. Using optical cables instead of copper cables can solve the problem of crowded underground communication pipelines in cities.   (3) The performance of fiber optic access networks continues to improve while prices continue to decline, while the price of copper cables continues to rise.   (4) The fiber optic access network provides data services with a comprehensive monitoring and management system, which can meet the needs of future broadband integrated service digital networks, break through bottlenecks, and ensure the smooth operation of the information highway.   Of course, compared to other access network technologies, fiber optic access networks also have certain disadvantages. The problem is that the cost is relatively high. Especially the closer the optical node is to the user, the higher the cost of access equipment shared by each user. In addition, compared to wireless access networks, fiber optic access networks also require pipeline resources. This is also why many emerging operators are optimistic about fiber optic access technology, but have to choose wireless access technology.   Nowadays, the main factor affecting the development of fiber optic access networks is not technology, but cost. However, the adoption of fiber optic access networks is an inevitable trend in the development of fiber optic communication. Although the steps for developing fiber optic access networks vary in different countries today, fiber to the home is widely recognized as the development goal of access networks.   Reference Terms Abbreviation Full name Abbreviation Full name FAT Fiber access network ODN Optical distribution network PON Passive optical network FTTH Fiber to the home EPON Ethernet Passive Optical Network FTTB Fiber to the building GPON Gigabit-capable Passive Optical Network FTTC Fiber to the curb XGPON XG-PON FTTO Fiber to the office XGSPON XGS-PON FTTP Fiber to the premises AON Active optical network FTTCab Fiber to the cabinet OLT Optical Line Terminal ONU Optical network unit NT Network terminal ONT Optical network terminal P2MP Point to multipoint CO Central office    

Fiber To The Home (FTTH) is a transmission method for fiber optic communication, which refers to the installation of optical network units (ONUs) at residential or enterprise users, and is the closest type of fiber access network application to users in the optical access series, except for FTTD (fiber to the desktop).   FTTH does not only providing greater bandwidth, but also enhancing the transparency of the network to data formats, rates, wavelengths, and protocols, relaxing requirements for environmental conditions and power supply, and simplifying maintenance and installation. PON technology has become a hot topic of concern for global broadband operators and is considered one of the best technical solutions for achieving FTTH.   FTTH (Fiber To The Home) is currently the best model for full service, high bandwidth access needs. Its development mainly has two paths: active optical networks and passive optical networks.   Active optical networks have the characteristic of long transmission distance, but they have a high degree of equipment specialization and are not suitable for densely populated areas. In addition, the port price is relatively high. Moreover, the active characteristics also greatly limit the installation of equipment and are easily affected by electromagnetic interference in the surrounding environment, which increases the number of network failure points and leads to high maintenance costs.   Passive optical networks, as pure dielectric networks, have a natural ability to resist electromagnetic interference, reduce the number of failure points in the access network, have high system reliability, and low maintenance costs. At the same time, the FTTH transparency of the passive optical network mode is good, which can support applications of multiple standards and is more suitable for large-scale development of users. Passive optical networks are gradually becoming the mainstream development direction of FTTH.   FTTH Main Business Scope FTTH is a comprehensive access solution for all services, allowing users to enjoy multiple services at the same time. Video: HDTV， Standard DTV, various still image services using MPEG-1, MPEG-4, and other compression technologies, and low resolution surveillance image services. Data: Data services with various code rates, ranging from a few Kbps to tens of megabytes. Voice: including traditional POS telephone and digital telephone services, multi-channel high fidelity sound. Multimedia: Various mixed data, voice, and image services of different qualities.   FTTH Networking Principle Similar to the "Cross and distribution method" of all plastic telephone cables, the Fiber to the Home (FTTH) Optical Distribution Network (ODN) is divided into a backbone cable subsystem, distribution cable subsystem, and drop cable terminal subsystem. (1) Backbone cable subsystem This refers to the optical cable distribution system between the central office optical distribution rack ODF connected to the fiber optic access equipment OLT and the user cable cross cabinet. In the fiber optic distribution equipment at both ends, the optical cables are terminated by thermal fusion and spliced with each other using cable tails.   (2) Distribution cable subsystem This refers to the fiber optic cable between the optical cross cabinet and the "fiber optic distribution box" inside the user's building. This is an optical distribution panel that directly connects the input cable and the output cable "back-to-back", usually with the splitting equipment also placed inside.   (3) Optical splitter (PLC) PLC splitter is a "fiber optic multiplexing device" that "multiplex" the channels of a single fiber optic cable into multiple channels, with a typical splitting ratio of 1:8, 1:16; 1: 32 and 1:64.   In the FTTH system of EPON mode, due to the transmission rate of 1.2Gb/s, the most commonly used splitting ratio is 1:32 to ensure that the user bandwidth reaches 30Mb/s or more.   According to their installation location, splitters can be packed by different type, including ABS module splitter, splitter tray, Splitter cassette,etc, and the connectors can be SC LC FC ST according to different customer request.   Advantages of FTTH Network FTTH is a passive network, can basically achieve passivity from the central office to the users; FTTH bandwidth is relatively wide, which perfectly fits the large-scale usage of operators over long distances; Due to its wide bandwidth, it supports flexible protocols; With the development of technology, relatively complete functions have been developed for point-to-point, 1.25G, and FTTH methods.   In the optical access family, there are FTTB (Fiber To The Building) fiber to the building, FTTC (Fiber To The Herb) fiber to the roadside, FTTSA (Fiber To The Service Area) fiber to the service area, and so on.   Directly connecting fiber optic cables to users' homes has no limitations on bandwidth, wavelength, and transmission technology types, making it suitable for introducing various new services. It is the most ideal business transparent network and the ultimate way for access network development.   Although the development speed of mobile communication is astonishing, due to its limited bandwidth, terminal size cannot be too large, and limited display screens, people still pursue fixed terminals with relatively superior performance, that is, hoping to achieve fiber to the home. The charm of FTTH lies in its huge bandwidth. It is the best solution to the "last mile" bottleneck from the Internet backbone to the user's desktop.   FAQ What is fiber to the home? Fiber to the home is a type of fiber optic access application that installs ONUs in the location of home users or businesses.   What services does FTTH provide? FTTH is a comprehensive access solution for all services, allowing users to enjoy multiple services simultaneously, including video, data, broadcasting, and multimedia.   What technology does FTTH use? Currently, GPON and EPON are the main technologies for FTTH PON network. GPON has stronger ability to support multiple services and better transmission efficiency.   How does FTTH work? There are two ways to develop FTTH, including active optical networks (AON) and passive optical networks (PON).   Due to PON being a pure dielectric network, it has a natural ability to resist electromagnetic interference. This leads to fewer access network failures, higher system reliability, and lower maintenance costs. In addition, FTTH in PON mode supports multiple applications and is suitable for large-scale expansion of user groups.   Therefore, the number of access network failure points is reduced, the system reliability is high, and the maintenance cost is low. Meanwhile, the FTTH of passive optical network has good transparency and can support multiple standard applications, making it more suitable for user scale development. Passive optical networks are gradually becoming the mainstream development direction of FTTH.   What equipment does FTTH need? The equipment used by FTTH mainly includes optical network terminals (OLT) and optical network units (ONU). The former is deployed in the ISP's office, while the latter is placed at the terminal. FTTH involves multiple industries such as indoor fiber optics, engineering, and applications, and is of great significance in the telecommunications and information industries.   Yingda can offer all types of fiber optic passive products in FTTH network: fiber optic distribution box, cross cabinet, ODF, fiber optic distribution cable, drop cable, and ONU, media converter, optical transceiver, WDM, optical splitter, patch cord and pigtails, etc. Welcome inquiry to sales@yingdapc.cn.  

Data center is a physical or virtual facility used for centralized storage, management, and processing of an organization's computer systems, network devices, and related components. These facilities have become particularly important in the digital age as they support various business needs, including data analytics, application hosting, cloud computing, and backup. This article will delve into the definition, functions，types and  applications of data centers.     What Is Data Center? A data center is a specially designed and maintained physical or virtual environment designed to provide organizations with highly reliable computing and storage resources. It includes servers, network devices, storage systems, power management, cooling systems, and physical security measures to ensure data security, availability, and performance. Data Center Functions Data storage and management: Data centers are used to centrally store and manage large amounts of data, including structured and unstructured data such as enterprise applications, files, and multimedia content. Computing resources: Data centers host a large number of servers and computing resources for running applications, virtualization, and cloud computing workloads. Network connection: The data center provides high-speed Internet connection so that employees, customers and partners can access data and applications. Backup and Disaster Recovery: Data centers implement backup and disaster recovery strategies to prevent data loss and business interruption. Physical and digital security: Data centers adopt physical and digital security measures to protect data from unauthorized access and network threats.   Data Center Types On premise data center: Built and operated by the enterprise itself to meet internal IT needs, with data and systems completely under the control of the enterprise.   Colocation data center: Enterprises rent data center space and basic services (such as electricity, cooling, network connectivity), place free devices in it, and the data center operator is responsible for maintaining the environment.   Cloud Data Center: Built specifically for providing cloud services such as Laas, PaaS, and SaaS, users can access cloud resources through the network without worrying about underlying hardware infrastructure. The transportation bureau center is usually highly automated, scaled, and has the ability to flexibly expand and contract.   Edge data center: a small, distributed data center that serves as a data generation source (such as IoT devices, user terminals) or user group for low latency, high bandwidth applications, reducing transmission pressure on the main data center.   Application of data centers in modern business and technology In the business field, data centers are an indispensable part of enterprise operations. They support critical business applications such as Customer Relationship Management (CRM), Enterprise Resource Planning (ERP), and Supply Chain Management (SCM) systems. In addition, data centers are also the cornerstone of driving modern technological trends such as digital transformation, big data analytics, and IoT LOT.   On a technical level, data centers are the foundation of cloud computing services, enabling models such as Software as a Service (SaaS), Platform and Service (PaaS), and Infrastructure Services (LaaS). With the popularity of mobile devices and the deployment of 5G, the role of data centers in processing and distributing massive amounts of data has become increasingly prominent.   Data centers are also crucial for scientific research, as they provide the required large-scale computing power for complex simulations and computations, driving progress in the fields of medicine, astronomy, and climate science.     Related Products of Data Center Our company Yingda can provide varieties of high density fiber optic products for data center 10G, 25G, 40G, 100G, 120G, 200G etc, including fiber optic connectors MPO MTP, optical modules and transceivers, AOC and DAC cables, cable assemblies, adapters etc, welcome inquiry to sales@yingadpc.cn    

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