Definition and Classification of Computer Networks
computer network definition
- The precise definition of a computer network is not unified
- The simplest definition of a computer network is: a collection of interconnected , autonomous computers
- Interconnection: Refers to the data communication between computers through wired or wireless methods.
- Autonomy: refers to an independent computer, which has its own hardware and software and can be run independently.
- Set: refers to the need for at least two computers
- A better definition of a computer network is: a computer network is mainly interconnected by some general-purpose, programmable hardware that is not specifically designed to achieve a specific purpose (for example, transmitting data or video signals). These programmable hardware can be used to transmit many different types of data and support a wide and growing number of applications.
- The hardware connected to the computer network is not limited to ordinary computers, but includes smart hardware such as smartphones.
- Computer networks are not designed specifically to transmit data, but can support a wide variety of applications
Computer network classification
Classified by switching technology
- circuit switched network
- message switching network
- packet switched network
Sort by user
- Public network: refers to a large-scale network funded and built by telecommunications companies. Public networks need to pay fees in accordance with the regulations of telecommunications companies.
- Private network: refers to a network constructed by a department for the special business needs of the unit. This network does not provide services to people outside the unit.
Classification by transmission medium
- wired network
- wireless network
Sort by coverage
- Wide Area Network WAN: The coverage range is from tens to thousands of kilometers. It can cover a country, region or even across several continents. Sometimes it is also called a long-distance network. The WAN is the core part of the Internet. Its task is to provide long-distance communication for the core router. High-speed connections to interconnect metropolitan area networks and local area networks distributed in different areas
- Metropolitan Area Network MAN: The coverage area is generally one city, which can span several blocks or even the entire city. Its operating distance is 5 to 50 kilometers. The Metropolitan Area Network is usually used as the city's backbone network, interconnecting a large number of enterprises, institutions and campus LANs. Metropolitan area networks have begun to become the information service infrastructure of new-generation cities, providing access and various information services to a large number of users, and there is a trend to integrate traditional telecommunications services, cable TV services and Internet services.
- Local area network LAN: Generally connected by microcomputers or workstations through high-speed communication lines, the rate is usually above 10Mbit/s, and it is geographically limited to a smaller range, such as a laboratory, a building or a campus, and the distance is generally within About 1 km, a local area network is usually owned, used and maintained by a certain unit alone. In modern times, a campus or enterprise usually has many interconnected local area networks. Such a network is usually called a campus network or an enterprise network .
- Personal Area Network (PAN): It is not used to connect ordinary computers, but is a network that connects electronic devices for personal use, such as portable computers, printers, mice, keyboards, and headphones, using wireless technology at personal work places. Therefore, Also often called wireless personal area network, the coverage range of wpan is approximately 10m
Classified by topology
Bus-type network: uses a single transmission line to connect computers. The advantages are that it is easy to build a network, convenient to add and remove nodes, and save lines. The disadvantage is that the communication efficiency is not high under heavy load. If any part of the bus fails, the entire network will be paralyzed.
Star network: Each computer is connected to a central device through a separate line. The central device was a computer in the early days, later a hub, and now it is usually a switch or router. This network topology facilitates centralized control and management of the network. The disadvantages are high cost
Ring network: It connects all computer network interfaces into a ring
Mesh network: Generally, each node is connected to other nodes by at least two paths. It is mostly used in wide area networks. The advantage is high reliability, but the disadvantages are complex control and high line costs.
