Fluke Networks: function of Link LED indicator in Fault Diagnosis

One of the most common faults in the daily network is that the site cannot access the Internet. PC users or network maintenance personnel should first look at the NIC, switch, or HUB indicators to determine whether the connection is normal. This is usually the correct procedure for fault diagnosis ), then, check the software settings on the PC. But is it possible to determine the cable or port problems through the LED lights on the NIC or switch? It has been proved by practice that it is the case that an incorrect decision is made based on the instructions given by the LED that it is a waste of time to find the fault in the wrong direction when solving the fault. So what can the LED light be helpful in fault diagnosis?
The most common LED lights on the port are green, and some are yellow or other colors. First of all, we need to understand that the functions of different manufacturers of LED lights may be different. Green LED lights are the most common. What does it mean? If the green LED light is not on, there must be a problem. This is the most intuitive and correct judgment. But if the green LED light is on, does it mean there is no problem? Both the nic and the hub port have two functions: send and receive. A green LED indicates that a signal is in, but it does not indicate that the signal can be sent normally. That is to say, you cannot simply use a green LED light at one end to determine whether the transceiver is normal. Then to judge whether the sending and receiving are normal, we need to look at the green LED lights at both ends. Usually the switch HUB) and the PC are not together, one is in the office and the other is in the data center, so it is not convenient to quickly check the LED lights at both ends. In particular, it is not easy to find the corresponding port on the switch of the data center when there is no good wiring identifier.
As for the yellow LED lights, some manufacturers define it as sending signals, and some as duplex or half duplex. Therefore, the judgment of the yellow LED light depends on the user's understanding of the NIC or switch HUB. If you do not know the meaning of the yellow LED lights of the NIC and switch, do not make any judgment. Otherwise, it may waste a lot of time in the wrong direction. The statistical data shows that the switch port and network card work in full duplex and half duplex) mismatch accounts for a considerable part of the fault.
To sum up, simply look at the green or yellow LED lights on the NIC or switch to make judgments on the cable, Nic or switch port. Otherwise, incorrect judgment due to a simple phenomenon will lead the fault diagnosis to go astray and waste a lot of time. In addition, there are still some problems, such as the cable string around the Split Pair), the NIC or switch is low in level, it is not possible to draw any conclusion from the LED light, however, these faults may cause intermittent or slow site faults. This problem occurs because the network maintenance personnel do not have some simple testing methods to help them quickly identify faults at the bottom of the network. The Network multimeter of fluke network is the best solution to these problems.

Test the connection string between a PC and a vswitch

Nettool

Network multimeter Nettool is a testing tool designed for network maintenance personnel to solve the most common network site connection problems. It can test the port level, working mode, PC settings, and network information of the cable, Nic, and switch HUB ). As shown in, NT can separately test a certain direction, such as the NIC or vswitch port, or connect NT to the nic and vswitch for both directions ). The cables can be inserted into two interfaces of the instrument to test the self-ring of the cables. As shown in. In addition, the tester can detect the crossover cable during online testing, or even use the instrument to replace it when there is no crossover cable. When the NT string is connected between the network card and the switch, it can automatically check whether the levels at both ends are normal, work in duplex or half duplex) and so on. As shown in.

Errors at both ends of the test

Various problems found

In addition, it can also test whether the network card works normally and automatically detect many problems. With this testing tool, you don't have to rely on uncertain guesses to solve common faults, which speeds up Fault Diagnosis and saves a lot of valuable time.