Use NetTool to troubleshoot network faults

Faults and tests:
A power user in Dalian has a site that has a slow access speed and is interrupted from time to time. The network adapter has been replaced and the PC settings have been checked. The problem cannot be determined. In addition, the problem still cannot be solved by changing the network cable to different ports of the switch. Other users connected to the vswitch are normal. After the user purchases the network multimeter, The NT-IL (online network multimeter) Access test for a few minutes, the tester shows on the side of the Switch Level intermittent low problem. Disconnect the network port. The length of the tester test cable is 85 meters. After switching the network cable to another vswitch, the fault will disappear and it is preliminarily determined that the original port of the vswitch is faulty.

Tip:

1. Some vswitches/hubs or some ports do not have a strong level drive capability. When the site is far away from the switch, the problem becomes apparent. However, such a fault is very difficult to find and time-consuming because it is an intermittent fault. After you change the network card, the fault disappears and you may think that the fault has been rectified. In fact, the fault was not ruled out, but did not occur in a short period of time after the NIC was changed. What you think of as a fault is simply ruled out from the surface, and there is no proof.
   
2. There is also a noteworthy Problem in the case described. When troubleshooting, you must first confirm that the fault is a site, several sites, local or global problem. In this way, the scope of the fault can be reduced as soon as possible. For example, in this case, why is there no such problem for sites connected to the same vswitch. However, the problem of changing other ports to the vswitch cannot be solved. After inspection, it is found that the distance between the faulty site and the switch is 85 meters, and the distance between other sites is within 40 meters. This indicates that the network port drive capability of the vswitch is faulty. When the distance of the site is out of a certain range, the drive level is insufficient.