Hub is neither short nor short. Hub is called "hub" in English.

"Hub" means "center". The main function of the hub is to regenerate, shape and amplify the received signal, so as to expand the transmission distance of the network, and at the same time concentrate all nodes on the node centered on it. It works in the first layer of the OSI (open system interconnect) reference model, that is, the "physical layer". Hub, like network card, network cable and other transmission media, belongs to the basic equipment in LAN and adopts CSMA/CD (a detection protocol) access mode.

Hub belongs to the bottom equipment of pure hardware network, and basically does not have the ability of "intelligent memory" and "learning" similar to switches. It also has no MAC address table owned by the switch, so it sends data by broadcast, not as a target. That is to say, when it wants to send data to a node, it does not send data directly to the destination node, but sends data packets to all nodes connected to the hub. This broadcast data transmission method has two disadvantages: (1) User data packets are sent to all nodes, which may bring unsafe factors in data communication, and it is easy for some people with ulterior motives to illegally intercept other people's data packets; (2) Because all data packets are sent to all nodes at the same time, the above-mentioned * * * bandwidth sharing mode is more likely to cause network congestion and further reduce the network execution efficiency. (3) Non-duplex transmission leads to low network communication efficiency. At the same time, each port of the hub can only carry out data communication in one direction, and it can't carry out bidirectional duplex transmission like a switch, so the network execution efficiency is low and it can't meet the communication needs of a larger network.

For this reason, although the hub technology is constantly improving, it has essentially added some switch technologies, and developed into today's stacked hub technology, and some hubs also have the function of intelligent switches. It can be said that hub products have been technically transformed to switch technology, and have certain intelligence and data exchange capabilities. However, with the continuous decline in the price of switches, the only price advantage is no longer obvious, and the market of hubs is getting smaller and smaller, and it is on the verge of elimination. Nevertheless, hubs are economically attractive to families or small businesses, especially suitable for networks with several computers at home or small and medium-sized companies as branch networks.