The main functions of the switch include physical addressing, network topology, error checking, frame sequence, and flow control. At present, the switch also has some new functions, such as support for VLAN (virtual local area network), support for link aggregation, and some even have the function of firewall.
In addition to connecting the same type of network, the switch can also play an interconnection role between different types of networks (such as Ethernet and Fast Ethernet). Many switches today can provide high-speed connection ports that support Fast Ethernet or FDDI, etc., for connecting other switches in the network or providing additional bandwidth for critical servers that consume a large amount of bandwidth.
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 port of the switch. In this way, key servers and important users of the network have faster access speeds and support greater information flow.
Learning function: The Ethernet switch learns the MAC address of the device connected to each port, 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).
Loop Elimination: When the switch includes a redundant loop, Ethernet switches avoid loops through the Spanning Tree Protocol while allowing backup paths to exist.
Learning: The Ethernet switch understands the MAC address of the device connected to each port, 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 adjacent to the destination node instead of all ports (if the data frame is a broadcast/multicast frame, it is forwarded to all ports) .
