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Exploration of Jianye Telephone Network Optimization

Abstract: This paper analyzes the current situation of the telephone network of Jian'ou City, according to the trend of communication development, and analyzes the application of transmission network, switching network and access network technology, and proposes the idea of ​​optimizing the telephone network of the city. Keywords: access network switching network transmission network optimization 1. Introduction The local telephone network is mainly composed of three parts: the relay transmission network, the switching network and the user access network. Currently, it is transmitted on the local telephone network. In addition to a small amount of low-speed data services, the main reason is still to transmit voice signals. With the deepening of reform and opening up, the market economy is becoming more and more active. People are not only satisfied with voice communication, but also put forward higher requirements for the rate of data communication. With the development of computer industry, people also require high speeds on communication lines. Data and images. The promotion of cable TV requires communication lines to carry CATV in order not to waste due to repeated construction. That is to say, the signal transmitted by the subscriber line is changed from a single voice signal to a plurality of service signals, and various communication services are integrated in the digital network, such as combining telephone, fax, telegraph, image, data, etc. into one network. This is the Integrated Services Digital Network. In recent years, the two parts of the relay transmission and exchange in the telephone network of Jian'ou City have been digitized. As long as the user access network is digitized, the end-to-end digital connection can be provided to the user to realize the integrated service number. Net, therefore, it is very important to flexibly adopt various user access network technologies to solve the communication needs. This is why we want to explore the direction of Jianye's user access network. II. Application Analysis of Access Network Technology Jian'ou City is located in the north of Fujian Province, on the southeast side of Wuyi Mountain. The city covers an area of ​​4233.1 square kilometers and has a population of about 500,000. The telephone penetration rate is not high. At present, all the user access in the urban area still uses the main cable, the distribution cable and other twisted-pair copper wires. Some towns and villages use the optical digital subscriber loop carrier and copper cable to receive the corresponding end office. Therefore, the urban user access network is mainly Should consider the solution of voice, data, image triple play, township villages mainly to meet voice communications, as far as possible to transmit CATV conditions. In order to give full play to the existing copper access network capabilities and reduce the cost of communication network construction, consider adapting to the future development of communication services. We must have an in-depth understanding of access network technology, clarify the development trend of access networks, and establish countermeasures for access network technology. Line pair capacity transmission system line pair capacity system is a multiplexing technology that uses a common circuit line to transmit multiple telephones between the exchange and the user terminal. Different efficient voice coding techniques can be used to transmit in both directions on a pair of subscriber lines. 2, 4, 8 digital voice, or digital loop multiplexing equipment that transmits 7 digital voices in two directions on two pairs of subscriber lines, the transmission distance is generally 3-5KM. Since such a line-to-boost system cannot guarantee transparent transmission of 64Kbit/s connection to connection line between users, excessive use of such a system will definitely affect the communication quality of the entire network. Therefore, this kind of equipment can only be used as an emergency measure to temporarily solve the shortage of subscriber lines, and cannot be included in the development plan of the access network. High-speed digital subscriber loop equipment High-speed digital subscriber loop transmission technology is a transmission technology based on the existing common copper wire. It uses advanced digital signal adaptive equalization technology and echo cancellation technology to eliminate near-end crosstalk in the transmission line. The interference of the echo caused by the impulse noise, waveform noise and line impedance mismatch, so that the 2Mbit/s digital signal can be transmitted in full duplex on the existing ordinary telephone twisted pair copper wire, and the relay transmission distance is up to 3-5KM. At present, HDSL technology is relatively mature. It provides users with 30B+D and 2Mbit/s services, and can also be used to transmit 30 channels of voice for the expansion of ordinary telephone services. Considering the current status of HDSL technology, it is feasible to adopt HDSL system in the near future, make full use of existing copper resources to realize user expansion and solve the demand of some users for broadband services. However, the HDSL system cannot transmit information above 2 Mbit/s, and the transmission distance does not exceed 5KM. It can only be used as a transitional measure for building an access network. Asymmetric Digital Subscriber Loop Transmission System Asymmetric Digital Subscriber Loop technology is based on the transmission of broadband services over ordinary telephone lines. The ADSL system consists of a central office transceiver and a client transceiver. This transceiver is actually a high speed data machine. The ADSL asymmetric performance is generally between 1.5-6 Mbit/s between the central office and the user end, and the transmission distance is up to 3.6 KM on the 0.5 mm twisted pair copper line. The low speed upstream channel rate is generally 16-640 Kbit/s. between. The ADSL signal and the basic audio telephone signal are passively coupled to the ordinary telephone line through a common telephone service splitter, and the high-speed downlink channel can transmit video, audio information, and control and overhead signals to the user. The low-speed uplink channel can transmit ordinary telephone services or control overhead signals to the network, that is, ADSL can provide a broadband service of 6 Mbit/s rate to the user while transmitting the telephone service on the ordinary telephone line. However, ADSL technology is still immature, and the equipment is expensive and cannot be used in the near future. Hybrid fiber/coaxial cable system Hybrid fiber/coaxial cable system uses fiber as the main transmission medium, adopts active fiber technology, and coaxial cable to users. HFC system is a broadband integrated service access platform, which can be divided by frequency division multiplexing. Transmitting voice, data, analog broadcast TV, digital video and other services, after the signal is photoelectrically converted at the node, sent to the network interface unit set in the user's home via the coaxial cable, and the signal output from the network interface unit to the user equipment is decomposed By making two telephone signals (or one telephone signal and one voice data signal) and one video signal, the user can receive the analog television signal through the external cable by using the existing television set. HFC has the characteristics of wide frequency, large capacity and point-to-multipoint transmission. Therefore, the development of HFC is more suitable for cable TV transmission. At present, Jianye City has not reached the relevant agreement on the construction of CATV with the broadcasting and television section, and the telephone business has been basically completed in one household. Therefore, this scheme is not economically or technically desirable. However, the radio and television sector is trying to compete with the HFC technology for the telecommunications business market. The optical fiber digital loop carrier system ODLC system generally consists of a central office and a remote unit. The basic principle is shown in Figure 1. As can be seen from the figure, the ODLC system first takes the analog signal from the Z interface of the exchange for analog conversion into a digital signal, and then multiplexes it into a light signal for transmission, and the remote receives the optical signal through photoelectric conversion. After the electrical signal is generated, it is connected to the user's telephone after repeated use and digital-to-analog conversion. The ODLC system is a fiber-optic access device used in the past few years. It has played a certain role in the construction of rural telephones in Jianye. However, with the advancement of technology, its technical means and economic performance are backward, which is highlighted in the following: Modular and digital-to-analog conversion equipment; 2 The user circuit board should be equipped at the central office and the remote end, which not only increases the cost, but also increases the fault point; 3 also occupies the user circuit board of the switch and wastes the number resources in the central office; 4 It is difficult to provide new services such as ISDN and data to the user, and cannot upgrade to the broadband user access network; 5 can not achieve 112 centralized testing. For these reasons, the development of such ODLC equipment should be discontinued. Of course, ODLC is also developing, such as the new single-ended open ODLC with V5 interface, and the market prospect is promising. Remote Module The remote module extends the user level of the switch to the remote end through the optical digital transmission device to solve the remote access problem of the telephone user. Strictly speaking, it does not belong to the category of access network, but because it can promote the construction of optical fiber to users, especially in terms of economy and technology, at the same time, the module bureau is reducing the number of offices, the best The network structure and so on also play a very important role, so it is widely applied. However, when the remote module is used, the module and the parent office are required to be the same manufacturer's device. The interface uses the internal protocol. When the capacity is expanded, the capacity of the parent switch is required to be expanded. You need to configure a dedicated interface circuit board. In ISDN, all the chassis in the module office are required to be ISDN user boards. The configuration is not flexible enough to provide access to broadband services in the future. RASM3 is a new type of remote user module for the S-1240 model introduced by Shanghai Bell, and IRSU and RASM1 are also introduced. The design is comprehensive and the performance is good. Optical fiber access network system Optical fiber access network refers to a transmission system that uses optical fiber communication between a local switch or a remote switching module and a user, and uses optical fiber as the main transmission medium to replace the traditional twisted pair copper wire. It is mainly composed of optical line terminals, optical distribution networks, optical network units, etc. The optical access network currently requires interconnection with switches with V5?1 and V5?2 interfaces; ODN mainly performs optical signal power distribution. The optical transmission means is provided between the OLT and the OUN; the ON U mainly provides a direct or remote user-side interface for the optical access network, and optically converts the optical signal to the user equipment. According to the distance that the optical fiber extends to the user, that is, the specific location of the ONU in the optical access network, the optical access network can be divided into several basic application forms: fiber to the roadside, fiber to the building, fiber to the home, and fiber to the office. The networking of the fiber access network is somewhat point-to-point, star-shaped, chain-shaped, and ring-shaped. The V5 interface mainly supports the following three types of services: the access of the telephone network user supports the access of the simulated user and the user switch. ISDN access supports 2B+D basic rate access and 30B+D base rate access for semi-permanent leased lines or permanently leased lines without out-of-band signaling, either analog or digital. The semi-permanent leased line passes through the V5 interface and permanently leases the line bypass V5 interface. In addition to narrowband services such as voice, data, and images, the main access network will also undertake future broadband service access, and currently provides CATV transmission functions. From an economic point of view, when the user backbone cable capacity is more than 2000 lines and the length exceeds 2KM, the fiber access is more economical than the existing copper line user loop. In addition, it also has many advantages such as less tube holes, easy maintenance, and future development. Fixed wireless access system? Fixed wireless access system, also known as wireless local loop system, is used to replace the copper wire in the customer network, providing the user loop between the connection switch and the fixed line, and the technical requirements of the mobile communication system. There are essential differences. The wireless local loop system is mainly composed of three parts: a base station controller, a base station, and a user terminal. The user terminals are distributed in the location of each user, and are connected to various communication terminals directly or through indoor and indoor wiring. The base station provides a wireless transceiving channel with the user terminal. On the one hand, the controller controls the allocation of the entire system, especially the wireless channel. The wireless local loop mainly adopts two technologies: 1. Public mobile network technologies such as FDMA, TDMA, and CDMA cellular system technologies are mainly used in underdeveloped areas with low population density or low service penetration rate, or difficult terrain lines due to poor terrain conditions. In the region, the base station has high output power and relatively low frequency, and the coverage radius can reach about 50KM, that is, the large-area system is adopted, and generally, there is no need to consider problems such as handover and roaming, and most of them are fixed users. The user side wireless terminal is directly connected to the fixed telephone via the conversion device. 2, cordless phone technology, such as DECT, PHS, etc. This type of system is mainly used in places where the population density is high and it is difficult to add new lines. The power of the base station is small, and the distance to the indoor wireless terminal is usually only about 500-1500M. Cordless technology can also provide users with a limited range of mobility, such as moving around 100M in the vicinity of the home. At this time, the base station is dense and needs to be considered for handover. A more complete system can be developed into an intra-domain second communication network with personal communication capabilities. The introduction of the ISDN service of the V5 interface of the access network requires transparent digital connection between the user terminal equipment and the local exchange. For this purpose, the digital interface that should have digital user access is called the V interface. Due to the insufficient standard of the V1-V4 interface, it is difficult to accommodate a variety of transmission media, multiple access configurations and service requirements of the user access network. Therefore, a V5 interface is produced. The V5 interface is further divided into V5.1 and V5.2 interfaces according to the number of connected 2Mbit/s PCM links and the functions of the user access network. The V5.1 interface uses a 2Mbit/s link to connect the switch to the user access network. The user access network does not include the concentrator function. It supports PSTN access and basic ISDN access. The V5.2 interface can connect up to 16 2Mbit/s links. The user access network corresponding to it can contain the concentrator function. In addition to the services supporting the V5.1 interface, it can also support ISDN base rate access. . In the future, a V5.3 interface supporting STM-1 rate and a V5.B interface supporting wideband ISDN will be proposed. Second, the current situation of the exchange network analysis The current local telephone exchange network is a star structure, the city has a central tandem office, which is the city's telephone exchange convergence center, responsible for the long-distance telephone and local network of the city's rural end offices The junction of the telephone is attached to the Nanping C3 local network. The city bureau switch adopts S1240E type machine, and there are five township end offices adopting DS-2000B type machine. There are four township end offices adopting HAX-80 00 type machine, and two township end offices adopt HJD-268 type machine, there are two The township adopts the S-1240 remote module RSU. The installed capacity is 500 except for Nanya and Dongfeng. The rest are 500. The end office and the tandem office use the China No. 1 signalling RSU bureau and the parent office. Internal common channel signaling is used. The S-1240E adopts decentralized control mode, with strong traffic carrying capacity, flexible software modification, full function, stable performance and technical support. However, this machine consumes a lot of power, has no N-ISDN function, and does not provide V5 interface. . Its remote module RSU has a small capacity and no internal switching function. It is time consuming to "live" to save "live". The new S-1240J model introduced by Shanghai Bell Company has N-ISDN function. On this basis, the V5 interface will be provided in the first half of 1998, and the newly designed large-capacity remote module RASM3 will be introduced. DS-2000B and HAX-8000 models have stable performance, small capacity, few business functions, difficult to open NO?7 signaling, cannot provide V5 interface, and are easy to maintain. These two models cannot meet the future development of communication services. Needed, can not smoothly expand, HAX-8000 type machine CPU failure, the billing part of the work stability is poor. The current networking method has the following problems: the number of end offices is large and the capacity is small, and each end office is connected to a central tandem office. If the tandem office has an unexpected disaster or a global block, the end office communication will be comprehensive. Blocked. There is only one exchange bureau in the urban area, which cannot achieve overlapping coverage of service areas, and cannot guarantee the communication security and reliability of important user units. There are many types of switching equipment, and it is difficult to achieve centralized monitoring and centralized maintenance. More transfer times. Most end offices are in urgent need of expansion. Third, the status quo of the relay transmission network analysis Center to the end office to use AT&T's 8T2664, 8TR663 equipment, using line-type point-to-point fiber transmission, only one 8Mb / s digital circuit per point. The number of full-capacity service circuits in the number of fields is 480. The performance of the device is stable, but the circuit is inconvenient. There are problems: the transmission line and transmission capacity are small, the circuit scheduling is not flexible; the transmission network has no self-healing capability, and is out of the game. After the circuit has only one direction and is 34Mb/s PDH equipment, several end stations are serially connected to one optical cable. Once the optical fiber is interrupted or the terminal is faulty, the subsequent communication between the end stations will be blocked. From this point of view, the transmission network is the basic network of communication, which carries all the networks such as the service network and the support network. Its reasonable network structure and flexible networking mode, especially security and reliability, are particularly important. The optical synchronous digital transmission series has been considered as an ideal physical transmission platform for the information highway in the future due to its many advantages. In the past two years, it has been widely adopted in China's communication network. Fourth, Jianye local network optimization ideas 1, the city bureau tandem office expansion of 10,000 doors, installed capacity of 26,000, will use S-1240J-type machine, and the original S1240E machine into a J-type machine, introduced New functions such as N-ISDN lay the foundation for achieving "large capacity and fewer accounts". At the same time, the two larger end offices of Dongfeng and Dongyou were changed to the new module RASM3 produced by Shanghai Bell Company, with a capacity of 2,000. After the trial is successful, it will be promoted to the use of major towns and towns, and the original end-office equipment will be transformed in the same way as “similar models, gradually merged, fully utilized, and retired from the network”. 2. Re-establish a gateway in the new development zone of Shuixi Railway Station in the urban area, adopting domestic large-scale switches, and gradually adopt the modules of users in seven townships of Xudun, Jiyang, Fangdao, Nanya, Dikou, Yushan and Xiaoqiao. Or the fiber access network equipment is housed in the water west end office, and the fiber optic access network is used to achieve "overlap coverage" of important units such as the municipal party committee, the municipal government, finance, and public security. In this way, the construction of a dual-telecom exchange will build a burden on the city's traffic load, reduce call loss, and enhance safety and reliability. 3. Selecting the fiber access network equipment to start the access network test. After investigation, it was decided to select the access network equipment of Zhongxingxin Company for testing and network structure diagram. In view of the fact that the S-1240E has not yet opened the V5 interface, the signaling converter will be temporarily set up. After the first half of 1998, Shanghai Bell Company will provide the V5 interface and then remove it. Therefore, the STE and OLT are installed in the central gateway office. Since the development of the access network is very sensitive to cost, on the basis of the success of the trial network, planning should be done to divide different access network communities, such as residential communities and financial communities, according to the needs of user service development, and consider Factors such as user attributes, types of business requirements, size of coverage areas, and physical geographic boundaries determine the size of the AN network, the type of equipment, and maintenance management and service management. In the construction of village dialects, in the principle of “high starting point”, basically, the optical cable is used according to the test of the access network, and it is determined that some townships end offices switch to fiber optic access equipment and install ONUs to the corresponding administrative villages. . 4. With the increase of the capacity of the Jianye telephone network, the capacity of the relay transmission network becomes a “bottleneck”. To solve this problem, the optical cable mesh network is first established, which lays a foundation for the PDH transition to SDH. Combined with the village telephone project, it is planned to establish three ring systems in the city: the ring one system: the cable of Jianye-Dongfeng-Yongyou-Chaoshi-Longcun-Komat-Jianyu will form a ring network; the ring system will: Jianye-Xiaoqiao - Yushan-Dikou-Nanya-Jianyu's optical cable forms a ring; the ring three system: the cable connection of Jianye-Xulund-Jiyang-Fangdao-Jianyu is formed into a ring. After the ring network is formed, the transmission circuits of each end station in the ring increase, which can basically meet the development needs of the past two years. Both of them realize the dual physical routing of relay transmission, and at the same time, according to the business needs, segmented core, SDH transmission Construction can take the form of overall planning and step-by-step implementation. In the initial stage, you can build a link with tight business requirements, and gradually improve the structure of the network when conditions permit. 5. For the new access network feeder segment, when the distance is ≥ 2KM, in principle, the cable will not be newly laid, and the optical cable will be used. The specific transmission technology can be flexibly selected according to the service needs and the network environment. The construction of the access network should be sufficient. The use of copper cables, new fiber optic cable, OAN access technology, HDSL, ADSL and wireless access for the shop, in the selection of equipment should pay attention to meet the requirements of maintenance and network management. Because the towns and villages of Jianye are surrounded by mountains, it is not appropriate to adopt wireless local loop technology, but the urban area is flat and open, and it can be used for small capacity after the mature CDMA technology is matured, mainly used to make up for the shortage of cable. Conclusion The optimization of the Jianye telephone network should be carried out in three parts: the switching network, the relay transmission network and the user access network. Due to the large proportion of investment in the access network, there are many types of access network technologies. It is not very mature. Therefore, it should be promoted after the experiment has gained experience, especially the test of V5 interface. The module technology is mature, and its special relay transmission technology should be paid attention to when applying. SDH is critical to the security and reliability of the entire telephone network, and it is necessary to transition from PDH to SDH in due course. The main line penetration rate of Jianye is just at the turning point from the take-off period to the big development period. In the next few years, the Jianye telephone will be in a big development stage, the market prospect is very promising, and the requirements for the types of telecommunications services will be increasingly improved. It is necessary to hurry up, keep up with the trend of new communication technologies, do a good job in the construction of communication networks, adjust and supplement in time, and let the communication construction develop in a healthy and orderly manner so that the communication network is continuously optimized. References: 1, Jiang Baishun, Xu Jijin, "Several problems in the application of access networks and their development strategies" "Telecom Technology" NO?8, P152, Che Lijun, Sha Weijin, "The optical digital loop carrier system Development" World Telecom, Vol. 9, No. 3, P 303, Qi Jiangxing, Chai Yuanbo, "Talk about V5 Interface", "Telecom Technology" NO?4 1997 P1?4, Shenzhen Zhongxing New Communication Equipment Co., Ltd. "ZXOAN Zhongxing Optical Connection Introduction to Network Access Technology 5, District Weiwei, “Re-discussion on the Construction of User Access Network”, “Modern Telecommunications Technology” NO.7.1996.7.P6 Figure 1 Fiber Optic Loop System Schematic Diagram Figure 2 Fiber Optic User Access Network Network structure diagram Figure 3 Jianye City optical cable routing diagram This news will cause the subsequent end office communication to block. From this point of view, the transmission network is the basic network of communication, which carries all the networks such as the service network and the support network. Its reasonable network structure and flexible networking mode, especially security and reliability, are particularly important. The optical synchronous digital transmission series has been considered as an ideal physical transmission platform for the information highway in the future due to its many advantages. In the past two years, it has been widely adopted in China's communication network. Fourth, Jianye local network optimization ideas 1, the city bureau tandem office expansion of 10,000 doors, installed capacity of 26,000, will use S-1240J-type machine, and the original S1240E machine into a J-type machine, introduced New functions such as N-ISDN lay the foundation for achieving "large capacity and fewer accounts". At the same time, the two larger end offices of Dongfeng and Dongyou were changed to the new module RASM3 produced by Shanghai Bell Company, with a capacity of 2,000. After the trial is successful, it will be promoted to the use of major towns and towns, and the original end-office equipment will be transformed in the same way as “similar models, gradually merged, fully utilized, and retired from the network”. 2. Re-establish a gateway in the new development zone of Shuixi Railway Station in the urban area, adopting domestic large-scale switches, and gradually adopt the modules of users in seven townships of Xudun, Jiyang, Fangdao, Nanya, Dikou, Yushan and Xiaoqiao. Or the fiber access network equipment is housed in the water west end office, and the fiber optic access network is used to achieve "overlap coverage" of important units such as the municipal party committee, the municipal government, finance, and public security. In this way, the construction of a dual-telecom exchange will build a burden on the city's traffic load, reduce call loss, and enhance safety and reliability. 3. Selecting the fiber access network equipment to start the access network test. After investigation, it was decided to select the access network equipment of Zhongxingxin Company for testing and network structure diagram. In view of the fact that the S-1240E has not yet opened the V5 interface, the signaling converter will be temporarily set up. After the first half of 1998, Shanghai Bell Company will provide the V5 interface and then remove it. Therefore, the STE and OLT are installed in the central gateway office. Since the development of the access network is very sensitive to cost, on the basis of the success of the trial network, planning should be done to divide different access network communities, such as residential communities and financial communities, according to the needs of user service development, and consider Factors such as user attributes, types of business requirements, size of coverage areas, and physical geographic boundaries determine the size of the AN network, the type of equipment, and maintenance management and service management. In the construction of village dialects, in the principle of “high starting point”, basically, the optical cable is used according to the test of the access network, and it is determined that some townships end offices switch to fiber optic access equipment and install ONUs to the corresponding administrative villages. . 4. With the increase of the capacity of the Jianye telephone network, the capacity of the relay transmission network becomes a “bottleneck”. To solve this problem, the optical cable mesh network is first established, which lays a foundation for the PDH transition to SDH. Combined with the village telephone project, it is planned to establish three ring systems in the city: the ring one system: the cable of Jianye-Dongfeng-Yongyou-Chaoshi-Longcun-Komat-Jianyu will form a ring network; the ring system will: Jianye-Xiaoqiao - Yushan-Dikou-Nanya-Jianyu's optical cable forms a ring; the ring three system: the cable connection of Jianye-Xulund-Jiyang-Fangdao-Jianyu is formed into a ring. After the ring network is formed, the transmission circuits of each end station in the ring increase, which can basically meet the development needs of the past two years. Both of them realize the dual physical routing of relay transmission, and at the same time, according to the business needs, segmented core, SDH transmission Construction can take the form of overall planning and step-by-step implementation. In the initial stage, you can build a link with tight business requirements, and gradually improve the structure of the network when conditions permit. 5. For the new access network feeder segment, when the distance is ≥ 2KM, in principle, the cable will not be newly laid, and the optical cable will be used. The specific transmission technology can be flexibly selected according to the service needs and the network environment. The construction of the access network should be sufficient. The use of copper cables, new fiber optic cable, OAN access technology, HDSL, ADSL and wireless access for the shop, in the selection of equipment should pay attention to meet the requirements of maintenance and network management. Because the towns and villages of Jianye are surrounded by mountains, it is not appropriate to adopt wireless local loop technology, but the urban area is flat and open, and it can be used for small capacity after the mature CDMA technology is matured, mainly used to make up for the shortage of cable. Conclusion The optimization of the Jianye telephone network should be carried out in three parts: the switching network, the relay transmission network and the user access network. Due to the large proportion of investment in the access network, there are many types of access network technologies. It is not very mature. Therefore, it should be promoted after the experiment has gained experience, especially the test of V5 interface. The module technology is mature, and its special relay transmission technology should be paid attention to when applying. SDH is critical to the security and reliability of the entire telephone network, and it is necessary to transition from PDH to SDH in due course. The main line penetration rate of Jianye is just at the turning point from the take-off period to the big development period. In the next few years, the Jianye telephone will be in a big development stage, the market prospect is very promising, and the requirements for the types of telecommunications services will be increasingly improved. It is necessary to hurry up, keep up with the trend of new communication technologies, do a good job in the construction of communication networks, adjust and supplement in time, and let the communication construction develop in a healthy and orderly manner so that the communication network is continuously optimized. References: 1, Jiang Baishun, Xu Jijin, "Several problems in the application of access networks and their development strategies" "Telecom Technology" NO?8, P152, Che Lijun, Sha Weijin, "The optical digital loop carrier system Development" World Telecom, Vol. 9, No. 3, P 303, Qi Jiangxing, Chai Yuanbo, "Talk about V5 Interface", "Telecom Technology" NO?4 1997 P1?4, Shenzhen Zhongxing New Communication Equipment Co., Ltd. "ZXOAN Zhongxing Optical Connection Introduction to Network Access Technology 5, District Weiwei, “Re-discussion on the Construction of User Access Network”, Modern Telecom Technology, NO.7.1996.7.P6

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