A network is a collection of computers or computer-like network devices connected by a variety of transport media. No matter how the devices are connected, the network transmits data from one network device to another network device through the transmission medium.
This section will explain the composition of a network based on this process.
The network card
A Network Adapter, also known as a Network Adapter, is the interface that connects a computer to the transmission media. Network cards are mainly used to convert computer data into signals that can be transmitted over a transmission medium.
To access the Internet, network devices need to be connected through network cards. The type of network card used varies with the Internet access mode. The types of nics are as follows:
1) Wired network card
A wired nic is a nic that connects to a network through a "wire". The "wire" in question here refers to the network cable. The following figure shows the common forms of wired nics.
2) Wireless card
In contrast to wired network cards, wireless network cards do not need to be connected through network cables, but through wireless signals. A wireless card is usually a wireless card for a Wi-Fi network.
3) Bluetooth adapter
A Bluetooth adapter is also a wireless network card. The difference between bluetooth adapter and wireless card is the way of data communication.
Classified by installation mode
A network adapter is usually a subordinate device of a network device. According to their installation mode, network adapters can be divided into built-in network adapters and external network adapters.
1) Built-in network adapter
As network cards have become necessary to connect to the network, many network devices have built-in network cards. Therefore, the built-in network card is also called the integrated network card. For example, today's motherboards are integrated with wired network cards.
2) External network adapter
Many network devices allow users to install additional network cards in addition to the built-in ones. This type of nic is called an external nic and is sometimes referred to as a standalone nic. Because it can be plugged into the motherboard in a variety of expansion slots, so it can be disassembled at will, with a certain degree of flexibility. The wired network card and wireless network card mentioned above are external network cards.
The network cable
Network cables are used to connect devices on the network for data communication between devices. Common network cables include twisted-pair cables, optical fibers, and telephone lines.
A twisted pair cable is a network cable. It consists of twining two copper wires with an insulating layer, as shown in the picture. There are eight such copper wires. Each one is distinguished by its corresponding color. In real life, computers in homes and businesses connect to the Internet through twisted pair cables. The sequence of these twisted-pair cables is usually EIA/TIA 568B, which is orange and white, orange, green and white, blue, blue and white, green, brown and white, and brown.
Optical fiber is a thin and soft medium for transmitting optical signals. Most optical fibers must be wrapped in several layers of protection before use. The main function of optical fiber is to convert the data to be transmitted from electrical signals to optical signals for communication. Optical cats are installed at both ends of the optical fiber for signal conversion.
A telephone line is the wire that connects a telephone. Telephone wires are also made of insulated copper wires. Unlike twisted-pair wires, telephone lines have only two or four wires, which are not necessarily wound together, and there is no color ordering.
Network devices refer to the devices in the network, such as switches, routers, and modems. They are terminal devices that send or receive data.
A Switch connects multiple network devices to form a LAN. It is a network device used for electrical (optical) signal forwarding, for data exchange.
A Router, also called a Gateway, is used to connect multiple logically separate networks. A logical network is a separate network or a subnet. When data is transferred from one subnet to another, the routing function of the router is used to complete the transfer. It will automatically select and set routes according to the situation of the channel, to the best path, in order to send signals. Routers are also used for data conversion. Routers are easily distinguishable from switches. The biggest difference is that routers have WAN and LAN interfaces, while switches do not.
A Modem, commonly known as a "cat," is a type of computer hardware. It translates the computer's digital signals into pulses that can be sent over ordinary telephone lines. These pulses are then picked up by another modem at the other end of the line and translated into the computer's digital signal language.