The hub, which has only two ports, called the bridge. The bridge needed to connect two network elements. Network with Hub is a "common rail". Data packets during transmission through the hub to be delivered to all computers connected to the LAN. There are two types of hubs. Passive hubs. These devices send a signal obtained without pretreatment.
Active hubs (repeaters mnogopostovye). Receive incoming signals, process them and send to the connected computers Switches Switches are needed to organize a closer connection between the computer network, the sender and the destination computer. In the process of data transmission through a switch in his memory can be written about MAC-addresses of computers. With this information, the switch is a routing table in which each of the computers listed him of belonging sion a specific network segment. When you receive a packet switch data, it creates a special internal connection (segment) between its two ports, using the routing table. It then sends the data packet to the appropriate port of the destination computer, based on information described in the packet header.
Thus, the compound is isolated from other ports, which allows computers to exchange information with maximum speed, which is available for the network. If switch there are only two ports, it is called a bridge. The switch provides the following capabilities: to send a packet with the data from one computer to the destination computer, increase the data rate Router A router on the principle of operation resembles a switch, but has a larger set of features, he examines not only the MAC, and IP-addresses of both computers involved in data transmission.