What is a Network Switch?

A network switch is a device that expands the network and can provide more connection ports in a sub-network in order to connect more computers. With the development of the communications industry and the advancement of the national economy informatization, the network switch market is steadily rising. It has the characteristics of high cost performance, high flexibility, relatively simple, and easy to implement. Therefore, Ethernet technology has become the most important LAN networking technology today, and network switches have become the most popular switches.

Network switch

In a broad sense,

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.

In addition to being able to connect to the same type of network, the switch can also interconnect between different types of networks, such as Ethernet and Fast Ethernet. Many switches today provide high-speed connection ports that support Fast Ethernet or FDDI, for connecting other switches in the network or providing additional bandwidth for key servers with large bandwidth consumption.

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 directly connect some important network computers to the ports of the switch. In this way, the network's key servers and important users 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 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).

Elimination of loops: When the switch includes a redundant loop, the Ethernet switch avoids the generation of loops through the spanning tree protocol, while allowing backup paths to exist.

Further training: The Ethernet AC machine appreciates the MAC address of the device connected to each port, and maps the address with the responding port and stores it in the MAC address table in the AC machine cache.

Forwarding / Filtering: When the destination address of a data frame is mapped in the MAC address table, it is forwarded to the port of the adjacent destination node instead of all ports (if the data frame is a broadcast / multicast frame, it is forwarded to all ports) .

1. The switch establishes a mapping of the address to the AC port based on the source MAC address in the received data frame, and writes it into the MAC address table.

2. The switch compares the destination MAC address in the data frame with the established MAC address table to determine which port to forward.

3. If the destination MAC address in the data frame is not in the MAC address table, it is forwarded to all ports. This process is called flooding.

4. Broadcast frames and multicast frames are forwarded to all ports.

The internet

The tight budget makes network professionals have to choose cheap network switch hardware when designing the LAN access layer.

These cheap network switches are naturally not at the same level as the relatively large manufacturers in terms of support, quality, and advanced functions, but some companies believe that buying these cheap network switches is sufficient to deal with the current situation.

Lower-cost vendors can offer a wide variety of lower-priced switches, including managed and unmanaged fixed-configuration Layer 2 switches, as well as a variety of fixed and modular Layer 2 and Layer 3 switches. ^[1]

For specific construction practices, please refer to the National Building Standard Design Atlas Smart Home Control System Construction Atlas 03X602 and the international standard specification EIA / TIA569 Business Building Communication Channel and Space Standard.

when

Hardware is still an important part of data center network equipment, but the impact of switch software cannot be underestimated.

It's hard to compare software with networking if it's not in a conversation about software-defined networking (SDN). However, the role of network switch software in a data center network has little to do with SDN.

For a long time, the most important thing when buying a network switch is the data in the specification table. Even in the era of commercial chips, hardware is still important. But as the way companies use the network continues to change, the features and functions of the underlying operating system in the data center become equally important.

How can the right network switch software make the network more flexible, smart, and cost-effective? Is a white box switch the answer? In addition to competitive prices and sufficient bandwidth, what other factors should network engineers consider when buying or upgrading their data center network? These issues will be explored in the next article, Switch software plays an increasingly important role in data center networks. ^[3]