Application point of view: Describes switch device status errors and faults

Switch Equipment is still quite common, So I studied the status error of Switch Equipment and shared it with you here. I hope it will be useful to you. Without any clue, I had to go to the Central Data Center of the organization, open the cabinet, and want to see if any switch in the LAN is not running properly.

The status of the signal lights in the control panel of each vswitch is carefully observed. The author finds that all the signal lights are green and blinking. Obviously, they are simply observed by the naked eye, it is difficult to determine whether the switch is working normally. It seems that I can only use the laptop to check and test each switch in sequence.

Through the network cable, the author first connects the laptop to the top switch device of the wiring cabinet, and opens the system operation dialog box, in which the Ping command is executed on the target gateway device address, the result returned by the test is displayed as normal, which indicates that the working status of the top switch is normal. Connect the laptop to the second vswitch device and run the Ping command in the same way to test the connection. The result shows that the IP address of the target gateway device can be pinged properly, it seems that there is no problem with the second switch device. Then, in the third switch device, when you perform the Ping test on the gateway device address, the system returns a test result such as "Request timed out". Is there a problem with the third switch?

I carefully observed this switch and found that the signal lights in the control panel of the switch are green and blinking, but in fact the 24 ports of the switch, only a few switching ports are connected with network cables. It is reasonable to say that only the signal lights corresponding to the switching ports that are connected to the network cables are green and blinking, the signal lights of other ports should not be in the green and blinking state. How can the signal lights corresponding to all switching ports become in this state? Apparently, the working status of the third switch is incorrect. After further checks, I found that the previous faulty workstation that cannot access the Internet happens to be connected to this switch, no wonder some workstations can access the Internet or some cannot access the Internet in the LAN.

After finding the cause of the fault, I plan to restart the switch device to check whether the switch has errors similar to cache overflow, because restarting can often solve many hidden faults of switch devices. After restarting the switch device, the author again performs an online test in the faulty workstation system. This time, when the IP address of the target gateway device is pinged, the command is successfully executed, when trying to access the network content again, it is also normal. It seems that by restarting the switch device, the failure of the switch status is solved successfully.

Fault solution Summary

Looking back at the entire troubleshooting process, it is not difficult to find that some workstations can access the Internet and some cannot access the Internet in the LAN, the reason is that all workstations that cannot access the Internet are connected to switches with incorrect status, while all workstations connected to switches in normal status can access the network normally. The reason why I took some detours in the Process of troubleshooting this fault is that as long as the signal lights in the switch control panel are green and flickering, the switch must work normally. In fact, the switch's Traffic Signal status sometimes deceives us.

In addition, in order to help your friends solve switch faults efficiently in the future, we recommend that you troubleshoot the switch in a proper order. In general, when a switch fails to work normally, we may troubleshoot the switch in the following order:

First, the physical lines connected to the vswitch are gradually checked from far to near. Considering that many network faults of the vswitch are often discovered by computers that keep the connection with it, therefore, when we check the failure of the switch, we should try to start from the terminal computer, and then check the network cable, switch port module, network jumper, switch equipment in turn, until the cause of the fault is found.

When we confirm that the switch is not working properly, we can perform a key inspection on the switch from the outside to the inside. For example, you can first observe the status of each port signal of the vswitch. Depending on the status of the signal, you can probably determine where the switch has encountered a fault. For example, if the Link light of a switch is not on, it means that there is a problem with the corresponding switching port or the network cable is not inserted. If the Link light is yellow and does not flash continuously, this means that the switch device is working on the 10 Mbit/s data transmission status at the moment. If the Link signal lights are green and keep flashing, it indicates that the switch is working on 100 Mbit/s transmission status.

If there is a problem inside the switch, we cannot rashly remove the switch device. In this case, we should check the switch system settings to eliminate the parameter configuration factors, when it is confirmed that there is a hardware problem, consider using other normal devices to replace.