Main functions and features of the switch
A switch is a network device used to forward electrical signals. It can provide an exclusive electrical signal path for any two network nodes connected to the switch. The most common switch is an Ethernet switch. Other common ones are telephone voice switches, optical fiber switches, etc.
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 a firewall.
Learning: The Ethernet switch understands the MAC address of the device connected to each port, and maps the address to 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) .
Elimination of loops: When the switch includes a redundant loop, the Ethernet switch avoids loops through the spanning tree protocol, while allowing the existence of backup paths.
In addition to being able to connect to the same type of network, the switch can also interconnect different types of networks (such as Ethernet and Fast Ethernet). Nowadays, many switches can provide high-speed connection ports that support Fast Ethernet or FDDI, etc., which are used to connect to other switches in the network or provide additional bandwidth for key servers that take up a lot of bandwidth.
Generally speaking, 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 port of the switch. In this way, key servers and important users of the network have faster access speeds and support greater information flow.
Finally, briefly summarize the basic functions of the switch:
1. Like a hub, the switch provides a large number of ports for cable connection, so that the star topology can be used for wiring.
2. Like repeaters, hubs, and bridges, when it forwards frames, the switch regenerates an undistorted square electrical signal.
3. Like a bridge, the switch uses the same forwarding or filtering logic on each port.
4. Like a bridge, the switch divides the LAN into multiple collision domains, and each collision domain has an independent broadband, thus greatly improving the bandwidth of the LAN.
5.In addition to the functions of a bridge, hub, and repeater, the switch also provides more advanced features, such as virtual local area network (VLAN) and higher performance.
Switching (switching) is a general term for technologies that send the information to be transmitted to the corresponding route that meets the requirements by manual or automatic equipment according to the needs of transmitting information at both ends of the communication. According to different working positions, it can be divided into wide area network switch and local area network switch. Wide-area switch (switch) is a kind of equipment that completes the information exchange function in the communication system.
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