What is this switch for?

The main functions of the switch include physical addressing, network topology, error checking, frame sequence and flow control. At present, switches also have some new functions, such as supporting VLAN (Virtual Local Area Network), supporting link aggregation, and some even have the function of firewall.

Learning: The Ethernet switch knows the MAC address of the device connected to each port, maps the address with the corresponding port, and stores it in the MAC address table in the switch cache.

Forwarding/filtering: When the destination address of a data frame is mapped in the MAC address table, it is forwarded to the port connecting the destination node, not all ports (if the data frame is a broadcast/multicast frame, it is forwarded to all ports).

Eliminating loops: When the switch contains redundant loops, Ethernet switches avoid loops by spanning tree protocol, while allowing backup paths.

Switches can not only connect the same type of networks, but also interconnect different types of networks (such as Ethernet and Fast Ethernet). Nowadays, many switches can provide high-speed connection ports supporting fast Ethernet or FDDI, which can be used to connect other switches in the network or provide extra bandwidth for key servers with large bandwidth occupation.

Generally speaking, each port of the switch is used to connect an independent network segment, but sometimes in order to provide faster access speed, we can directly connect some important network computers to the ports of the switch. In this way, the key servers and important users of the network will have faster access speed and support greater information flow.