What are the hardware and software of the communication network, and what are the uses of each? 30

The communication system is generally composed of three parts: the sender (source and transmitting equipment), the channel receiving equipment (the host and the receiving device), and the noise source.

The source is the ** of the information, and its function is to convert the original signal into the corresponding electrical signal, that is, the baseband signal. The function of the transmitting device is to perform various transformations and processing of the baseband signal, such as amplification and modulation.

The channel is the transmission medium for transmitting the signal, and the host is the receiver of the information, corresponding to the source. The function of the receiving device is the opposite of that of the sending device, which processes and transforms the received signal.

A noise source is a concentrated representation of noise in the channel and scattered elsewhere in the communication system.

Commonly used network communication equipment is as follows:

1. Switches.

Switching technology is used to increase the sum of data input and output and the bandwidth of the mounting medium. Typical switches** have very low latency and can economically divide the network into small, collision domains, providing higher bandwidth for each workstation. It can be understood as an advanced bridge, which has the function of a bridge, but the performance is stronger than that of a bridge.

Second, the bridge. A bridge, also known as a bridge, is a storage device that connects two LANs, and can be used to connect network systems with the same or similar architecture.

3. Repeater.

It is a device that connects network lines, and is often used for the two-way work of physical signals between two network nodes. The repeater is the simplest network interconnection device, which mainly completes the function of the physical layer, and is responsible for transmitting information bitwise on the physical layer of two nodes, and completing the function of replication, adjusting and amplifying the signal, so as to extend the length of the network.

It is a simple signal amplifier, the signal is attenuated in the process of transmission, and the role of the repeater is to amplify the signal so that the signal can be transmitted farther.

Fourth, the router.

A router is a connection at the network layer, that is, a connection between different networks. The choice of path is the main task of the router. Path selection includes two basic activities: one is the determination of the best path; The second is the transmission of inter-network information packets.

5. Gateway. A gateway (protocol converter) is a facility with a protocol translation function that operates on top of the OSI network layer in an interconnected network, so it is called a facility because the gateway is not necessarily a device, and it is possible to implement the gateway function in a host.

Commonly used network equipment includes: computers (whether they are personal computers or servers), hubs, switches, bridges, routers, gateways, network interface cards, wireless access points, printers and modems, repeaters, etc.

1. Connected devices in the network include network adapters, repeaters, hubs, transmission lines, etc.

2. Inter-network connection devices include bridges, routers, etc.

Generally, there are the following devices: Network adapter: also known as network interface card (network card), it is plugged into the bus of the computer to connect the computer to other network devices, and the network adapter generally only realizes the functions of the network physical layer and the data connection layer.

Network transceiver: It is an interface device for network adapters and transmissions. It provides signal level translation and signal isolation.

Network Conversion Equipment: It is a conversion device between different transmissions in the network. Such as twisted pair and optical fiber, etc.

Multiplexer: A type of terminal controller. It is used to improve the utilization of communication channels.

Interrupter: also known as a disruptor, extends the transmission distance, such as an Ethernet interrupter can be used to connect different Ethernet segments to form an Ethernet. Hub:

Abbreviation, hub, can be regarded as a multi-port interrupter (one interrupter is dual-port) The above devices are all network devices working at the physical layer. Bridge: Two LANs can be connected into a logical LAN.

Network-connected devices that operate at both the physical and data connection layers. Switches: Early switches were the equivalent of multi-port bridges.

Router: An interconnected device that operates between multiple networks at the network layer. It provides the ability to select paths between networks.

Gateway: It can be regarded as a general term for multiple interconnected devices between networks, but generally refers to the equipment that realizes the interconnection of multiple networks above the transportation layer, also known as the application layer gateway. View the original post

The communication system consists of the source (sender). The host (receiver), channel, message, and protocol are composed.

The source is the sender of the message, and the host is the receiver of the message. A message is the content of data sent by both parties to the communication, including text, audio, data, etc. The channel is the medium of message transmission, which can be a wired transmission channel such as optical fiber and coaxial cable, or a wireless transmission channel such as wifi; A protocol is a rule that both parties to a communication follow when sending data.

This includes how communication is set up, datagram format, etc.

Generally, it is composed of the source (originating equipment), the destination (receiving equipment) and the channel (transmission medium), and the kiricha is called the three elements of communication.

The defibrillation information (language, text, image or data) from the source is first converted into an electrical signal by the terminal equipment (such as a ** machine, teletypewriter, fax machine or data terminal device, etc.) at the sending end, and then the baseband signal is converted into a form suitable for transmission in the transmission medium after being coded, modulated, amplified or transmitted by the originating device.

It is transmitted through the transmission medium, and is restored into a message at the receiving end through the receiving device and provided to the recipient. Most of this point-to-point communication is transmitted in both directions. Therefore, there are both sending and receiving devices at both ends where the communication object is located.