Switches are classified into managed switches and unmanaged switches according to whether they can be managed or not. Managed switches can be managed through the following methods: management through RS-232 serial port (or parallel port), management through web browser, and through Network management software management.

1. Serial port management
The network management switch comes with a serial cable for switch management. First plug one end of the serial cable into the serial port on the back of the switch, and plug the other end into the serial port of an ordinary computer. Then power on the switch and the computer.The “Hyper Terminal” program is provided in both Windows98 and Windows2000. Open the “Hyper Terminal”, after setting the connection parameters, you can interact with the switch through the serial cable without occupying the bandwidth of the switch, so it is called “Out of band”.

In this management mode, the switch provides a menu-driven console interface or command line interface. You can use the “Tab” key or arrow keys to move through the menus and submenus, press the Enter key to execute the corresponding commands, or use the dedicated switch management command set to manage the switch. Switches of different brands have different command sets, and even switches of the same brand have different commands. It is more convenient to use menu commands.

2. Web management
The managed switch can be managed via Web (web browser), but an IP address must be assigned to the switch. This IP address has no other purpose except for the management switch. In the default state, the switch does not have an IP address. You must specify an IP address through the serial port or other methods to enable this management method.

When using a web browser to manage the switch, the switch is equivalent to a Web server, but the web page is not stored in the hard disk, but in the NVRAM of the switch. The Web program in the NVRAM can be upgraded through the program. When the administrator enters the IP address of the switch in the browser, the switch passes the web page to the computer like a server, and it feels like you are visiting a website, as shown in Figure 2. This method occupies the bandwidth of the switch, so it is called “in band management” (In band).

If you want to manage the switch, just click the corresponding function item on the webpage and change the switch parameters in the text box or drop-down list. Web management can be carried out on the local area network in this way, so remote management can be realized.

3. software management
Network management switches all follow the SNMP protocol (Simple Network Management Protocol), which is a set of network equipment management specifications that comply with international standards. All devices that follow the SNMP protocol can be managed through network management software. You only need to install a set of SNMP network management software on a network management workstation, and you can easily manage the switches, routers, servers, etc. on the network through the LAN. The interface of the SNMP network management software is shown in Figure 3. It is also an in-band management method.

Summary: The management of a managed switch can be managed in the above three ways. Which method is used? When the switch is initially set up, it is often through out-of-band management; after setting the IP address, you can use in-band management. In-band management Because the management data is transmitted through a publicly used LAN, remote management can be achieved, but the security is not strong. Out-of-band management is through serial communication, and data is only transmitted between the switch and the management machine, so the security is very strong; however, due to the limitation of the length of the serial cable, remote management cannot be realized. So which method you use depends on your requirements for security and manageability.