According to computer network coverage, computer networks can be divided into three categories: 1. Local area network (LAN), which is a network composed of multiple computers used in a small area. The coverage is usually limited to Within 10 kilometers; 2. Wide Area Network (WAN) is a long-distance network that involves long-distance communications. The coverage can be a country or multiple countries, or even the entire world; 3. Metropolitan Area Network (MAN), which Network coverage can usually extend to the entire city, using communication optical fibers to connect multiple local area networks to public city networks to form a large network.
The operating environment of this tutorial: Windows 7 system, Dell G3 computer.
There are different classification methods for networks from different perspectives, and each network name has a special meaning. The combination of several names or names plus parameters can better reveal the characteristics of the network. Gigabit Ethernet represents a bus-type network with transmission rates up to Gigabit. Understanding the classification methods and type characteristics of networks is one of the important foundations for becoming familiar with network technology.
According to the coverage of computer network, computer network can be divided into: local area network (LAN), wide area network (WAN), and metropolitan area network (MAN).
Local area network (LAN)
Local area network (local area network) is usually referred to as "local area network", abbreviated as LAN. A local area network is a computer network with the least structural complexity.
A local area network is a network composed of multiple computers used in a small area. The coverage is usually limited to 10 kilometers, and it belongs to a small-scale network established by a unit or department.
A local area network is just a group of computers connected through a network at the same location. LANs are usually very close together and are currently the most widely used type of network. A network with the following characteristics is usually called a local area network.
1) The geographical scope covered by the network is relatively small. Usually no more than a few dozen kilometers, or even just within a building or a room.
2) The information transmission rate is relatively high, ranging from 1Mbps to 10Mbps, and has reached 100Mbps. The transmission rate of WAN operation is generally 2400bps, 9600bps or 38.4kbps, 56.64kbps. Dedicated lines can only reach 1.544Mbps.
3) The operation and management rights of the network belong to a certain unit.
Wide Area Network (WAN)
Wide area network (WAN) is a complex network system with wide influence.
WAN is a long-distance network that involves long-distance communications. The coverage can be a country or multiple countries, or even the entire world. Since the geographical distance of wide area networks can exceed thousands of kilometers, information attenuation is very serious. This type of network generally requires leased dedicated lines and is connected through interface information processing protocols and lines to form a mesh structure to solve the routing problem.
WAN consists of two or more LANs, and the connections between these LANs can traverse a distance of more than 30mile*. A large WAN can consist of many LANs and MANs on various continents. The most well-known WAN is the Internet, which consists of thousands of LANs and WANs around the world.
Sometimes the boundaries between LAN, MAN and WAN are very unclear, and it is difficult to determine where the LAN ends and the MAN or WAN begins. But the type of network can be determined by four network characteristics - communication medium, protocol, topology, and boundary points between private and public networks. Communications media are electrical cables, fiber optic cables, radio waves, or microwaves that connect computers to networks. Typically LANs end where the communication medium changes, such as from wire-based cables to fiber optics. A wire and cable LAN is usually connected to other LANs through optical fiber cables.
Metropolitan Area Network (MAN)
Metropolitan Area Network (Metropolitan Area Network) is a computer communication network established within a city, referred to as MAN. It is a broadband local area network. Due to the use of LAN technology with active switching elements, the transmission delay in the network is small. Its transmission medium mainly uses optical cables, with a transmission rate of more than 100 Mbit/s.
An important use of MAN is as a backbone network, through which hosts, databases, and LANs located in different locations in the same city are connected to each other. This function is similar to that of WAN, but the two There are great differences in implementation methods and performance.
Based on a large LAN, usually using technology similar to LAN. One of the main reasons why MAN is listed separately is that there is already a standard: Distributed Queue Dual Bus DQDB (Distributed Queue Dual Bus), that is, IEEE802.6. DQDB is composed of dual buses, and all computers are connected to it.
The typical application of metropolitan area network is broadband metropolitan area network, which is based on IP and ATM telecommunications technology and uses optical fiber as the transmission medium to integrate data, voice and video services within the city. A multimedia communication network with high bandwidth, multi-function and multi-service access.
Broadband metropolitan area network can meet the growing demand for high-speed and high-quality data communication services from government agencies, finance and insurance, universities, middle and primary schools, companies and enterprises, especially the rapidly developing Internet user group. The demand for broadband high-speed Internet access.
The development of broadband metropolitan area networks has gone through a long period, from traditional voice services to image and video services, from basic audio-visual services to various value-added services, from 64 kb/s basic services to 2.5 Gb/s, 10 Gb/s, etc. leased line services. With the development of technology and the increasing demand, the types of business are also constantly developing and changing.
The gradually improving urban broadband metropolitan area network in our country has brought many conveniences to our lives. High-speed Internet access, video on demand, video calls, online TV, distance education, distance conferencing, etc. are what we are using. Behind various Internet applications, metropolitan area networks play a huge role.
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