The Structure of the LAN Cable

The structure of the LAN cable
A local area network is usually a network system distributed in a limited geographical area, generally only a few kilometers in the geographical area involved. The local area network is very specific and has a relatively stable and standardized structure.
1. Star structure
A star consists of a central node and sites (network workstations, etc.) connected to the central node through point-to-point links. The star is centered on the central node and implements a centralized communication control strategy. Therefore, the central node is quite complex, and the communication processing burden of each station is very small, which is also called a centralized network. The network configuration of the star structure is simple, the network construction is easy, the control and management are convenient, and the transmission speed is fast. However, this kind of network system has low network reliability and poor network sharing ability, and once the central node fails, the entire network will be paralyzed.
2. Tree structure
The tree structure network is a natural hierarchical structure, also known as a hierarchical centralized network. It is characterized by low network cost and relatively simple structure. In the network, no loop is generated between any two nodes, each link supports bidirectional transmission, and the nodes in the network are convenient and flexible to expand, and it is relatively simple to search for the link path. But in this kind of structural network system, except for the leaf node and its connected link, the failure of any one workstation or link will affect the normal operation of the entire network system.
3. Line structure
A bus-like structure network connects each node device to a bus. All node workstations in the network transmit information through the bus. The communication connection as a bus can be a coaxial cable, a twisted pair, or a flat cable. In the bus structure, the load energy of the hello line, which must pass through data communication, is limited, which is determined by the physical performance of the communication medium itself.
Therefore, the number of workstation nodes in the bus structure network is limited. If the number of workstation nodes exceeds the bus load energy, it is necessary to extend the length of the bus and add a considerable number of additional switching components to make the bus load meet the capacity requirements. . The linear structure network is simple, flexible, and has good scalability.
Therefore, it is very convenient to insert and remove the node device. In addition, the bus structure network has high reliability, fast response speed between network nodes, strong ability to share resources, less equipment investment, low cost, and easy installation and use. When a workstation node fails, it has little impact on the entire network system. Therefore, the bus-structured network is the most commonly used one. However, since all workstations communicate through a shared bus, the real-time performance is poor.
4. Ring structure
The ring structure is a closed-closed ring structure network in which each node in the network is connected by an end-to-end communication link. The structure of the ring structure network is also relatively simple, and the status of each workstation in the system is equal. Communication equipment and lines in the system are relatively economical. In the network, the information has a fixed direction and one-way flow, there is only one path between two workstation nodes, and there is no channel selection problem in the system; the failure of a node will lead to physical paralysis. In the ring network, because the loop is closed, it is inconvenient for charging, the system response delay is long, and the information transmission efficiency is relatively low.