As for the components of the e-government website operation platform, this section will Website construction The introduction of hardware and network infrastructure platform, including the access part of e-government website (discussed from the perspective of network infrastructure construction), server hardware, and fire prevention for government security.
We will review the network infrastructure construction of e-government websites from several aspects, such as the access media of network access, the access methods necessary for government units to access external networks and the public to connect to e-government websites, various network connections and communication equipment used for government units to connect internal and external networks, such as hubs, switches, routers, etc. The transmission medium and its connector are the carrier of signal transmission on the sample network and the basis of network operation. Government departments should build internal networks and access external networks to provide services. You need to choose the right media for your entertainment. In the actual process of building a station, the selection of transmission media is affected by many factors, such as the type of information to be transmitted between computers, the transmission distance, the external environment on the way to transmission and the type of network built. There are also many types and specifications of transmission media. Therefore, this book only gives a brief introduction here, so that relevant developers can have a general understanding of them.
(1) Twisted pair. Twisted Pair Wire (TP) is the most commonly used transmission medium. Twisted pair consists of two 22-26 copper wires with insulation protection, which can reduce the influence of signal interference. A twisted pair cable is formed by placing one or more twisted pairs in a conduit. Twisted pair cable is relatively cheap, but its transmission speed and distance are limited, so it is often used for short distance information transmission. Twisted pair is most suitable for equipment connection between points in the local network. Without intermediate devices, the maximum distance without distortion of twisted pair transmission box signal is 100 meters. However, when using twisted pair to transmit information, the signal will radiate to Zhou Gang and be easily eavesdropped. The International Electrical Industry Association (EIA) has defined eight types of twisted pair cables
(2) Coaxial cable. Coaxial cable is composed of a single inner conductor enclosed by a hollow cylindrical conductor. Its frequency characteristic is better than that of twisted pair cable, and it can carry out high speed transmission. Its anti-interference ability is A, and its shielding performance is good. It is often used for baseband transmission. All parts of the coaxial cable are connected through the low loss alf connector. The physical performance of the connector is matched with the electrical system. Coaxial cable used for computer network generally selects RG-8 Ethernet thick cable (5051) or RG-58 (509) Ethernet thin cable.
(3) Optical waveguide. Optical fiber is a thin and flexible medium for transmitting light beams. Optical fiber cable is composed of a bundle of fibers, which is called optical fiber cable for short. It has the following advantages: ① it has a wide frequency band; ② it has good electromagnetic insulation performance, is not affected by electromagnetic interference and does not radiate signals, so it is suitable for long-distance information transmission and occasions requiring high safety; ③ The attenuation is small, and the distance between amplifiers is large. Because the optical system can only transmit data in one direction, it must be used in pairs when two-way communication is required, one for input and the other for output. Both ends of the optical group must be connected to the optical interface device
(4) Wireless communication. Wireless communication uses communication satellites to realize data transmission. It is divided into point-to-point satellite emblem wave lines and broadcast satellite emblem wave communication lines. Because satellite ground stations are expensive, the wireless communication network system is mainly used for a large number of information processing systems
(5) Transmission media connector. The most commonly used transmission medium connectors are: T-type connector, RJ-45 unshielded twisted pair connector, DB-25 interface, V35 synchronous interface, etc. The T-connector and BNC connector are thin coaxial connectors. The coaxial cable and T-connector are based on the BNC connector. The RJ-45 unshielded twisted pair connector has 8 connecting pins. In the IIlL SE-T standard, only 4 connectors are used: DB-25 interface, namely R, 232 interface, which is the current common way of connecting the machine to the bus, DB-15 interface is the AVI interface used to connect the network interface card; V35 interface is the high-speed synchronization interface used to connect the remote.
