What are the differences between hubs, routers, and switches?

Hubs, switches, and routers have become the three swordsmen in network hardware. So, what is the difference between the three?


The conceptual difference between the three:

The hub belongs to the data link layer in the OSI model. It is the same as the transmission medium such as twisted pair, and does not require any software support or only requires little hardware management software. Cheap price is the biggest advantage, but because the hub is a shared device, resulting in heavy networks, the efficiency becomes very low, so we basically can not see the hub in the medium and large networks. Nowadays, hubs generally adopt full-duplex mode, and the transmission speed of common hubs on the market is generally 100Mbps.


The switch is a network device based on MAC (hardware address of network card) identification, which can complete the function of encapsulating and forwarding data packets. The switch can "learn" the MAC address and store it in the internal address table. By establishing a temporary exchange path between the originator and the target receiver of the data frame, the data frame directly reaches the destination address from the original address.


The router  is a network device that works on the third layer (network layer) of OSI, has the ability to connect different types of networks, and can select a data transmission path. The router has three characteristics: working on the network layer, being able to connect to different types of networks, and being able to choose the path of data transmission.