Wireless network troubleshooting steps

Network troubleshooting can be encountered in actual projects. After encountering problems, we need to have a clear solution to the problem, so that we can find out the problem quickly, then let us look at it.

First, the basic steps of network troubleshooting

Troubleshooting Network Problems For some older engineers who are more experienced and savvy, it is possible to find the problem quickly. But in fact, they are also accumulating experience little by little, and they can be summed up so quickly and efficiently. Therefore, for novices, they must not be too anxious. If they want to be in one step, they should be implemented step by step and gradually accumulate from the foundation. Here we must first understand the five major steps in network troubleshooting:

(1) Look at the symptoms first.

(2) List as many reasons as possible for the symptom.

(3) Then check for each reason.

(4) Find the reason.

(5) Solve the problem.

The second step is very critical, because the more possible causes are found, the greater the success rate of troubleshooting

Second, troubleshooting cases

The sequential process is especially important. It reflects the logic of a person. Here is a simple example to familiarize yourself with the specific steps:

The figure is the customer's network topology diagram. Two APs are connected to one POE switch, one gateway device is connected to the POE switch, and a “cat” (modem) is connected to the gateway. Now customers use their mobile phones to receive only network signals, but they don't even have access to the Internet.

First of all, we should follow the order in the wrong order, here we use the order from bottom to top. When the phone is connected to Wifi, if there is no signal, we will gradually analyze from the AP:

AP:

(1) The POE switch does not supply power to the AP. After the AP is powered off, it naturally leads to no signal.

(2) In order to prevent the network, the SSID of the AP is hidden, and the search signal is not found.

(3) AP performance, AP performance includes hardware and software. The hardware is divided into CPU-function-antenna. If any part of the problem occurs, the AP performance may be poor, and no signal can be found.

POE switch:

(1) The hardware failure causes a problem in the power supply, and the AP has no power, so no signal can be found.

(2) The problem of the network cable causes a problem with the connection.

(3) The rate or working mode of the switch port does not match. When the traffic is too large, the rate is insufficient. As a result, the AP goes offline and cannot find the signal gateway:

Gateway:

(1) Power failure, POE switch does not supply power.

(2) If the dial-up is unsuccessful, the username and password may be incorrect, or the dial-up may fail due to the configuration of the gateway itself.

After analyzing so many reasons, we can test one by one and the problem can be solved easily. However, now the customer's situation is that there is a signal, can not access the Internet, so it is necessary to go from step to step. Mobile phone networking can actually be divided into two steps:

The first step, the principle of mobile phone access through wireless wifi is to scan the SSID, that is, to find the signal name and encryption method, that is, to find the name of WIFI, enter the password to join.

The second step is to try to connect to the network:

(1) If the signal is unstable during the connection process, it may be a performance problem of the AP. The AP performance includes the software part + hardware part, or it may be caused by interference.

(2) If the IP address is displayed during the connection process, it means that the mobile phone can access the AP, that is, the AP has power and works normally, then the AP and the POE switch are normal;

(3) If the IP can be successfully obtained, it means that the DHCP function of the intranet part of the gateway, that is, the dynamic allocation of the IP address function is normal, then the gateway intranet part is no problem. However, the external part of the gateway cannot be defined. Then only the part of the gateway external network to the "cat" section, can receive the signal but can not access the Internet, analysis of the reasons, may be the wrong insertion of the network cable, should be inserted into the gateway's external network interface (Wan port), or can not access When you go to the Internet, you will not be able to get online.

(4) Of course, there is also a common fault, that is, the problem of the network cable. Problems occur in the process of making the crystal head of the network cable, which may also cause various kinds of network failures.