-Computer networks in primary and secondary schools at all levels.
Yosie Wong huadu district beixing town Liu Hua high school
abstract:
Network education has been paid much attention by the educational circles because of its wide audience, low investment, unrestricted by teachers' places, easy to carry out high-level education and relatively easy to ensure teaching quality. At present, some websites of major universities in China have carried out this application. But now the primary and secondary school campus network is in the construction stage. The fundamental motivation of computer network construction in primary and secondary schools is to improve the management efficiency and teaching quality of schools. Not only a large amount of capital investment and the construction of a large-scale computer network can be used for school education. Establishing a small local area network and teaching network can meet the application needs of the school and bring great educational benefits.
Keywords: network card hub LAN server
In the construction of computer networks in primary and secondary schools, different schools can build different levels of computer networks according to their own characteristics and actual conditions. In other words, qualified schools can invest in building a relatively perfect campus computer network at one time, while other schools can build some small local area networks first, and then gradually improve the campus network according to the actual situation. Conditions refer to capital, school size, computer knowledge of computer users and technical ability of computer professionals. Therefore, when the level of personnel applying and developing computer networks is good, they can make full use of the computer networks they use. Otherwise, it is best not to rush to build a large-scale and complex computer network.
I. Network connection mode
1, bus structure
This is a widely used way in early NOVELL networks. It is a typical bus topology with a network transmission rate of 10Mbps.
The file server and the student workstation are connected through a 50 ohm thin coaxial cable, which runs through the whole network, and the maximum network segment does not exceed185m. The student workstation is equipped with a network card with BNC socket, and the computer connects the network card with the coaxial cable through a T-connector, and each connection is regarded as a node. The network segment must be connected to a 50 ohm terminator with one end grounded.
The disadvantage of this structure is that if one node in the network fails, it will affect the normal operation of the whole network and lead to the paralysis of the whole network.
2. Star structure
The topology of this networking mode is star, and the transmission rate reaches 10Mbps. Different from the traditional bus structure, a hub is added in the topology structure, and all workstations are connected to the hub through unshielded twisted pair (UTP). In actual networking, hubs are often connected into a bus structure with thin coaxial cables, and the workstations on each hub are connected in a star shape. The distance between twisted pair and student workstation shall not exceed 100 meters.
Each student workstation in the star network structure is equipped with a network card with RJ-45 interface, which is connected with the RJ-45 interface of the hub through a twisted pair connected with RJ-45 connector. Because HUB has the function of dynamically monitoring network operation and fault tolerance, the failure of a node in the network only affects the student workstations connected to the node, but does not affect the normal operation of the whole network.
Network construction can have the following different levels:
1, Local Teaching Network (LATN) is applied to the computer local area network of the teaching classroom, and there are two forms:
One is the ordinary computer local area network, which connects the computer as a server with the computer as a workstation without additional equipment and provides the usual network functions. This way can realize the sharing of software and hardware on the network, which is of great help to the management of the computer room. But it does not provide convenience for classroom teaching interaction (unless special software is compiled). There is also a teaching network in the classroom, that is, on the basis of the above-mentioned network, a hard card (LATN card) is attached to each computer to switch between audio and video analog signals, and the screen information of teachers' computers and teachers' voices are switched to students' computers, or the screen information of students' computers is switched to other computers to assist teachers in classroom teaching. Teaching network has low cost and strong practicability, and has a broad market at present. However, due to the form of analog signal transmission, the transmission distance is limited, which is limited to one classroom. All digital information transmission is the ultimate trend of network development.
Local teaching networks usually provide the following teaching functions:
Two-way language teaching system for teachers and students.
A broadcast function that transmits the display content of a teacher's computer to all or part of the screen of a student's computer.
Teachers supervise and check the control function of students using computers.
Teachers convey the function of students' operation to students.
The function of students asking questions and teachers answering questions on the computer.
2. Small office peer-to-peer network
By establishing a peer-to-peer network of small office computers, you can share all kinds of office resources: printers, hard disks, intermediaries, documents and other materials. , so that all kinds of * * * shared files do not need to be transmitted between machines through floppy disks, which reduces the workload and the possibility of computer virus spread and improves the utilization rate of equipment. This networking form has low requirements for equipment and is easy to implement. Especially in the environment of Win95 and Win98, the operation is very convenient.
Additional equipment required, general routing network structure: coaxial cable, network card, twisted pair, hub.
Network card: Small offices only need 10M Ethernet, but each PC can be configured with 10/ 100 network card to move to fast Ethernet if necessary.
Hub: It runs at the speed of 10 or 100Mbps, and provides additional ports to meet the development needs.
Printer: There are three forms of printer * * *: (1) The easiest way is to install a buffer for printing * * *.
Connect multiple PCs that need printing services to realize the enjoyment of printers, and there is no requirement for computer networks; (2) an ordinary printer connected to a PC and set as a print server; (3) The network printer connected as a network device runs faster. At present, some computer companies have also introduced multifunctional printers that integrate network printers, fax machines, scanners and photocopiers.
3. Small client server LAN
As an interconnection method, client-server LAN has more network functions than peer-to-peer network. This includes the management of network system resources, network security management and so on. This includes the management of network system resources, network security management and so on. When a department or department in a school needs to share resources and provide certain security measures for managing files and resources on the computer, it is necessary to adopt the client/server form based on the network.
The network operating system of LAN can choose MS Windows NT, Novell Nerware and UNIX. At present, it is often used to support more software. Windows NT is more suitable for Windows-based clients. When customers often use DOS system as the operating platform and have more requirements for file services, it is best to choose Novell Netware to establish a small client/server LAN, and it is best to have a dedicated server. PC, Pcserver and dedicated server with better performance belong to different levels of servers, which can meet the needs of different levels.
For primary and secondary schools, libraries, computer classrooms with teaching networks and catering systems can all establish small local area networks.
4. The whole school computer information network
When it is necessary to connect all kinds of computer equipment in the whole school to realize an information management system and teaching applied to the whole school, it is necessary to establish a campus computer information network for the whole school. There is no exact definition of the concept of "campus network", and there is no unified standard for the construction of campus network. Literally speaking, the campus information network for the whole school should refer to the computer network system applied to the computer education of information management in the whole school. Each school has its own characteristics because of its own application needs and different architectural environments, but the most fundamental purpose is to improve the educational efficiency of the school.
Before establishing the campus computer information network, we need to consider the following questions:
(1) What functions does the computer campus network need to provide, and the feasibility of application requirements (including technical feasibility and requirements for users)?
(2) How much money can the school bear? What is the investment to complete the required functions?
(3) What is the input-output ratio of building a campus network?
(4) Can other cheaper and more reasonable means be used to achieve the same function?
(5) Will there be a long-term development plan for the construction of campus network? Has the school itself further applied its development power?
A complete campus network system should usually include the following parts:
(1) Campus information service system.
(2) database service system; Including the principal's office system; Student management system; Educational administration management system; Financial management system; Asset management system; Restaurant life management system; File management system.
(3) Educational resource management inquiry system.
(4) CAI application system.
(5) Email system.
The core function of campus computer network in primary and secondary schools is to provide * * * access to various information resources; * * * Sharing of teaching resources, * * * Sharing of educational knowledge, * * * Sharing of management information, and strengthening between teachers and students and between teachers. The interaction between managers and teachers provides a foundation for the modernization of school education and the scientific management. According to the current technical development, the establishment of campus network will be the information management technology adopted in the construction of campus network.
Second, the construction mechanism of computer network
1, the construction of computer network, especially the construction of computer campus network, needs a systematic and comprehensive analysis and
Planning process. Due to the long construction period, network management, maintenance and software system development should be managed by special personnel. From the point of view of perfecting the network, it is also necessary for someone to engage in the development of network applications for a long time. Therefore, the primary task of network construction is to establish a network construction team including school leaders, technicians, logistics personnel and heads of various departments and groups. Through the mutual cooperation of the team members, * * * completed the network building workbench and the later application development and maintenance work.
2. A project requirement analysis model combining top-down and iterative prototype method is adopted.
The traditional life cycle method emphasizes the top-down development mode, and requires that requirements must be strictly defined before actual development to improve the success rate of software development. Prototype method is to improve the design scheme through continuous modification and expansion after obtaining a set of basic requirements through preliminary analysis.
3. Multi-party and multi-party scheme authentication
Network construction scheme is the blueprint of campus network, which should not only reflect the application needs of the school, but also be practical and correct in network technology, and need reasonable capital investment. Generally speaking, making a plan requires the following steps:
(1) Form a preliminary plan according to the demand analysis.
(2) Discussion scheme of school and system integration.
(3) Ask the network expert group to discuss the scheme.
(4) Form the final network construction scheme.
4. Network implementation method of third-party supervision
For the implementation of network construction projects, although system integrators have project quality assurance schemes, ordinary primary and secondary schools do not have the corresponding technical force to supervise network construction projects.
5. Pay attention to the development of application systems to ensure the "sustainable development" of network applications.
For the construction of campus network, the completion of network hardware can only be regarded as half of the whole work. Compared with setting up a network, the construction of a network application system is more complicated, with large hidden workload, long construction period and low profit.
6. Perfect network management system and application development plan.
A perfect network, if no one uses it, means nothing. While building a network, schools can't ignore the construction of application teams.
Design, including: network management technicians: network application developers: network users (teachers, students, employees, etc. )
Therefore, at the same time of computer network construction, it is also required to have a reasonable training plan and establish a team to develop and apply networks.
The "Teacher Fan Training Model" in Singapore's "Master Plan" is worth learning. In this plan, teachers trained by the Ministry of Information will train other teachers through part-time work, and this workload will be converted into one-third of their own work. The fan-shaped teacher training model will produce twice the result with half the effort.
At the same time, the use and management system of the network should also be synchronized with the network application to ensure the normal operation of the network.
refer to
China Audio-visual Education? Xu Zhou Jiang Fuxi
Computer education news? Huang Mingdong Long Aizhen
Contemporary educational science translation, introduction to educational technology? Wurenze Chunqiu Publishing House
Contemporary educational scientific translation, the application of computers in modern education? Zhang Chunqiu Publishing House