【 Weak current College 】 switch malfunction general classification and troubleshooting steps

The network administrator at work often encounter a variety of switch failure, how to quickly and accurately detect the failure and troubleshooting? this article in respect of common fault type and troubleshooting steps for a brief introduction. Because of the switch in the corporate network application range is extensive, from low-end to the mid-tier, from midrange to high-end, almost every level of the product, so switch the chance of failure than a router, such as a hardware firewall is much higher, which is why we first discuss switch failure categories and troubleshooting steps.
First, switch failure classification:
Switch fault in General can be divided into hardware failures and software faults. Hardware failures are mainly refers to switch the power supply and backplane, module, port and other parts of the fault can be divided into the following categories.
(1) power failure:
Because the external power supply is unstable, or power line aging or lightning, and other causes corrupt or fan stopping power, and thus does not work properly. Because of the power that cause damage to other parts within things often happen.
If the POWER led on the Panel is green, that is normal; if the light is off, the switch does not have the normal power supply. This problem is very easy to find, is also very easy to solve, but also the most easily preventable.
For such a failure, first of all should do the external power supply, usually by introducing separate power line to provide independent power source, and add the regulator to avoid transient-voltage or low voltage. If conditions allow, you can add a UPS (uninterruptible power supply) to guarantee the normal power switch, UPS provides voltage function, and some not, pay attention to when choosing. In the engine room set professional lightning protection measures, to avoid damage to the switch and lightning. There are so many do lightning engineering professional company, implementation of network wiring can be considered.
(2) port failure:
This is the most common hardware failures, fiber optic ports or twisted pair RJ-45 port, plug connector must be careful. If you accidentally fibre plug dirty, can cause fiber port pollution rather than normal traffic. We often see many people like to electrification-plug connector, in theory, Yes, but it also inadvertently increase the port's failure rate. When you are not careful handling, can also cause physical damage to the port. If you purchase Crystal head size too large, into the switch, you can easily destroy the port. In addition, if you add in the port of twisted pair some exposed outdoor, in case the cable were struck by lightning, will result in even the switch port is striking, or cause more unpredictable damage.
In General, the port is a fault or damage several ports. Therefore, when troubleshooting a port connected computer failure, you can replace the connection port, to determine if it is damaged. Experience this type of failure, you can turn off the power supply, with alcohol tampon cleaning port. If the port is corrupted, it can only replace the port.
(3) module fault:
The switch is made up of many modules, such as: stacking module, management module (also called control module), the extension module. These module failure probability is very small, but when problems arise, they will suffer huge economic losses. If you swap modules accidentally, or handling switches is subjected to collision, or power instability, this can cause this type of failure.
Of course, above these three modules are external interface, easier identification, you can also use the led on the module to identify the failure. For example: stacking module has a flat trapezoid-port switch, or a similar to a USB interface. Management module has a CONSOLE port, and network management to connect your computer to facilitate management. If the extension is fiber connections, there will be a pair of optical fiber interface.
To exclude such failure, first make sure the power switch and module, and then examine the normal supply of each module is inserted in the correct location, last check connection module cable properly. When the connection management module, but it is provided for connection rate, parity, flow control, and other factors. Connect the extension module, you need to check for matching modes of communication, such as: use full-duplex mode or half-duplex mode. Of course if you confirm the module failed, the solution is only one, that is, you should immediately contact the vendor for a replacement.
(4) backplane failure:
Switch for the module is a patch on the back panel. If the environment is wet, damp circuit circuit board, or components due to factors such as high temperature, lightning strike damage will have Board does not work properly. For example: thermal performance is poor or the environment temperature is too high, causing the tank temperature instigated components burn out.
In the external power supply properly, if you switch the internal modules are not working properly, it may be a backplane is broken, this is the case even if the electrical maintenance engineer, I am afraid it is last resort, the only solution is to replace the back panel.
(5) cable fault:
In fact, such a failure in theory, does not belong to switch their fault, but in actual use, cable fault often lead switch system or port does not work, so here are the kinds of failures into switch hardware failure. For example, connectors and plugs are not tight, cable production order errors, or when no specification, cable connection should use the crosshair but uses a direct line, cable in the two fibre cross connection, the error line connections are causing network loops, etc.