A hub (ie HUB, physical layer device) is a device that […]
A hub (ie HUB, physical layer device) is a device that connects multiple twisted pairs or optical fibers under the same physical medium. It usually works at the physical layer (the first layer of the OSI reference model) and is used to connect to a local area network. segment. The hub has multiple ports. When one of the ports receives a signal, it will shape and amplify the attenuated signal, and then broadcast the amplified signal to all other ports so that all segments of the LAN can see the data packets. In the network, the hub acts as a common connection point for devices.
A switch is a network device used for optical/electrical signal forwarding. It usually works at the data link layer or network layer (ie, the second and third layers of the OSI reference model) and supports various data packet protocols. At present, there are many types of switches, such as LAN switches and Ethernet switches. Among them, the local area network switch is mainly used for data exchange in the switched local area network; and the Ethernet switch is mainly used for data transmission in the Ethernet. In the network, a switch is a device used to filter and forward data packets between LAN segments.
A router is a device that connects various LANs and WANs in the Internet. It is usually located at the gateway of two or more network connections. It works at the network layer and is used to implement two LANs or two WANs or a LAN and Internet service provider Network connection. There is usually a routing table in the router, which will automatically select and set the route according to the channel conditions, and then send the signal with the best path. In addition, the router supports Internet Control Message Protocol (ICMP) and other similar protocols, which can help IP hosts and routers transfer control messages, and configure the best route between any two hosts.