How are wide area network, metropolitan area network and local area network divided?

WAN, MAN and LAN are divided based on “coverage”. The coverage of LAN is generally within a few kilometers. Its characteristics such as convenient installation, cost saving, and convenient expansion make it widely used in various offices. A wide area network is a long-distance network that connects computer communications in local area networks or metropolitan area networks in different areas, covering a range from dozens to thousands of kilometers. A metropolitan area network is a computer communication network established within a city.

Computer networks are divided into wide area networks, metropolitan area networks and local area networks. The main basis for their division is: the role (coverage) scope of the network.

Computer network refers to the connection of multiple computers and their external devices with independent functions in different geographical locations through communication lines. The management of network operating systems, network management software and network communication protocols A computer system that realizes resource sharing and information transfer under and coordination.

There are different classification methods for networks from different perspectives, and each network name has a special meaning.

• According to the scope of the network, computer networks can be divided into wide area networks, metropolitan area networks and local area networks.

• According to the network topology, the network can be divided into bus type, ring type, star type and other structures.

• According to the communication method of the network, computer networks can be divided into point-to-point transmission networks and broadcast transmission networks.

• According to the transmission medium of the network, computer networks can be divided into wired networks, optical fiber networks, wireless networks, etc.

LAN (Local Area Network)

The coverage of a local area network is generally within a few kilometers. It has the advantages of convenient installation, cost saving, Features such as easy expansion make it widely used in various offices. The LAN can realize functions such as file management, application software sharing, and printer sharing. During use, by maintaining the security of the LAN network, it can effectively protect data security and ensure the normal and stable operation of the LAN network.

A local area network is naturally a regional network formed in a local area. Its characteristic is that the distribution area is limited, which can be large or small. It can be as large as the connection between a building and an adjacent building, or as small as an office. the relationship between. Compared with other networks, the LAN itself has faster transmission speed, more stable performance, simple framework, and closed nature, which is why many organizations choose it. The local area network itself is generally composed of computer equipment, network connection equipment, and network transmission media. Computer equipment includes servers and workstations, and network connection equipment includes network cards, hubs, and switches. Network transmission media is simply Network cable is composed of three major components: coaxial cable, twisted pair and optical cable.

A LAN is a private network, typically within or near a building, such as a home, office, or factory. Local area networks are widely used to connect personal computers and consumer electronic devices, allowing them to share resources and exchange information. When LANs are used in companies, they are called enterprise networks.

A local area network connects various computers, external devices and databases in a certain area to form a computer communication network, and connects to local area networks or databases in other places through dedicated data lines to form a larger information processing system.

LAN connects network servers, network workstations, printers and other network interconnection devices through network transmission media to realize system management files, share application software, office equipment, send work schedules and other communication services.

The LAN is a closed network, which can prevent information leakage and external network virus attacks to a certain extent, and has high security. However, once an incident such as a hacker attack occurs, it is very likely to cause the entire LAN to be paralyzed. All work within the network cannot be carried out, and a large number of company secrets may even be leaked, causing serious damage to the company's business development.

MAN (Metropolitan Area Network)

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.

Metropolitan area network is divided into 3 layers: core layer, aggregation layer and access layer:

• The core layer mainly provides high-bandwidth service bearing and transmission to complete Interconnection with existing networks (such as ATM, FR, DDN, IP networks) is characterized by broadband transmission and high-speed dispatch.

• The main function of the aggregation layer is to provide the business access node with the aggregation and distribution processing of user business data, and at the same time to achieve service level classification of the business.

• The access layer uses a variety of access technologies to allocate bandwidth and services to realize user access. The access node equipment completes the multiplexing and transmission of multiple services.

WAN (Wide Area Network)

Wide Area Network (English: Wide Area Network, abbreviated as WAN), also known as wide area network, external network, public network . It is a remote network that connects computer communications in local area networks or metropolitan area networks in different areas. Usually spans a large physical range, covering a range from tens to thousands of kilometers. It can connect multiple regions, cities and countries, or span several continents and provide long-distance communications, forming an international network. remote network. WAN is not the same as the Internet.

The transmission medium of WAN mainly uses telephone lines or optical fibers, and ISP operators connect enterprises. These lines are pre-buried under the road by ISP operators. Because the project is huge, maintenance is difficult, and the bandwidth is It can be guaranteed, so it will be more expensive in terms of cost.

The Internet generally refers to a public wide area network. The cost of a public wide area network will be lower and it is a cheaper online environment. However, compared with a wide area network, it cannot be managed. Bandwidth, using a public online system, the bandwidth of any section cannot be guaranteed.

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