What is the function of the switch?

The main functions of switch include physical addressing, network topology, error checking, frame sequence, and flow control. At present, switch also has some new functions, such as support for VLAN (virtual local area network), support for link aggregation, and even some firewall functions.

Learning: Ethernet switch understands the MAC address of each port connected to the device, and 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 connected to the destination node instead of all ports (if the data frame is a broadcast/multicast frame, it is forwarded to all ports).

Eliminate loops: When a switch includes a redundant loop, the Ethernet switch avoids loops through the Spanning Tree protocol while allowing for the existence of a fallback path.

In addition to being able to connect to the same type of network, switches can also serve as interconnects between different types of networks, such as Ethernet and Fast Ethernet. Many switches today offer high-speed connection ports that support Fast Ethernet or FDDI, и т. д., for connecting to other switches in the network or to provide additional bandwidth for critical servers with high bandwidth usage.

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