The role of network switches

The functions of network switches are: 1. Physical addressing; 2. Network topology; 3. Error checking; 4. Frame sequence; 5. Flow control; currently switches also have some new functions, Such as support for VLAN, support for link aggregation, and some even have firewall functions.

The operating environment of this article: Windows 7 system, Dell G3 computer.

A network switch is a device that expands the network and can provide more connection ports in a subnetwork to connect more computers. With the development of the communications industry and the advancement of informatization of the national economy, the network switch market has shown a steady upward trend. It has the characteristics of high cost performance, high flexibility, relative simplicity and easy implementation. Therefore, Ethernet technology has become the most important LAN networking technology today, and network switches have become the most popular switches.

Function

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 support for VLAN (Virtual LAN), support for link aggregation, and some even have firewall functions.

In addition to connecting the same type of network, the switch can also interconnect between different types of networks (such as Ethernet and Fast Ethernet). Many switches today are able to provide high-speed connection ports that support Fast Ethernet or FDDI, etc., to connect to other switches in the network or to provide additional bandwidth for critical servers that consume 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 speeds, we can directly connect some important network computers to the ports of the switch superior. In this way, key servers and important users of the network will have faster access speeds and support greater information traffic.

Learning function: The Ethernet switch learns the MAC address of the device connected to each port, 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) forwarded to all ports).

Eliminate loops: When the switch includes a redundant loop, the Ethernet switch uses the spanning tree protocol to avoid the occurrence of loops while allowing backup paths to exist.

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

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