【 Weak current College 】 network management with network failure of five common blind spot---Power By 【 China power house network 】

As a network administrator, in the actual maintenance network, experience network failure is almost inevitable. From symptoms to look for a network failure solution is the same, but in the actual operating environment, addressing the same phenomenon of failure, may be very different; if we solve network problems, bad brains, vulnerable to some general dogmas, eventually causing network problems solving efficiency is not high. 　　On the contrary, if we can rut, seldom the blind spot to start to solve network problems, maybe can receive a multiplier effect. Here are a few network troubleshooting experience and share.　　Jumper laid flat LAN network built some time, during this time the network has been operating normally. Can last a few days, because of the switch cover dust too many reasons or outside interference, LAN often have several workstations doesn't go online, this phenomenon is the author often simply replacing a switch port, or simply to switch and workstation network adapter to connect the cable between your jumper can eliminate no Internet access. Can these two days have a workstation encountering the same network failure, the author attempts to use the previous workaround to troubleshoot network problems, I found the previous method actually doesn't work. Later, I was on the failed computer to switch the connection line between a detailed inspection, but never found suspicious. In despair, author on LAN switches over the jumper is direct and network line tester to connect information point there directly and failure are connected to the computer, and then make the signal testing to find the network tester Control Panel 1, 2, 3, 6, all in a light condition.　　Later, when I direct the jumper and switch connected to a port, even when the computer was unable to surf the Internet found fault symptom disappear immediately, but after many days after the computer has no network connection does not appear. Through this network trouble shooting action, we can seeclearly the day after the encounter out conventional methods are unable to resolve the network connectivity failure, we try to connect a jumper cables, which perhaps could receive unexpected results. Alignment to start in the local area network environment, we sometimes encounter network problems, it is a workstation in the correct logon into the Windows system, and open the local network neighborhood window, you can only see the name of the local computer, but cannot see the name of the other computers in LAN. Typically, in the Network Neighborhood window as long as you can see the local computer name, it indicates that the installation on the local computer's network adapter devices in terms of hardware is not a problem, but also that network driver installation is correct.　　In view of the local connection, other property parameters found various parameters configuration is correct. To view a network connection when the physical line, I see the connect to the computer's network cable stay very long in the wiring of staff may consider that the alignment is artistic factors, will excess cable mutual binding together, when the author will together of opening all of the cables, once again into my network places window, the Network Neighborhood window not only appeared in the local computer name, the name of another computer in the LAN is also displayed.　　Then view the information on the Internet, I found that when the computer uses ordinary twisted pairs as connection media, if you connect the two nodes of twisted pair cable length is greater than 100 meters, then network traffic signals will produce substantial attenuation, eventually leading to the local computer does not communicate properly with the LAN. In addition, twisted-pair cable for alignment, if people with extra cable mutually binding together, then network connections of communication lines has been artificially increased the value of inductive reactance, so can easily lead to signal an error occurred during transmission. Preinstalled start as we all know, in a bulk purchase of some brand of computer, computer vendors tend to be good for Windows operating system preinstalled, but also for our direct configured network. But when we apply these good operating system preinstalled and configured the network parameters of the computer, access to the units of the local area network, a network connection is not stable, often for a minute to go online and do not have access to the Internet. Check those unstable computer on the Internet, we found these computer network parameters configured and no errors.　　Then check the PC and switch the connection line between physical, I found physical lines are connected, but I do not trust the connectors for contact with laminate, specifically to the individual connector pull down and reseat it, but such efforts or unable to eliminate computer cannot be stable Internet access. Later I will those faulty computer to reinstall the operating system, and according to the original network configuration set their Internet access parameters are configured, and then place them in the access to the LAN. Summary This is a network fault, the author believes that the purchase of large quantities of computer, computer vendors in order to save the time of the installation system, they tend to use the network or hard disk cloning methods, to help us pre-installed operating system and configure your network parameters.　　But once the machine tools and machines of various components install location is different or individual component model is not exactly the same, then through the Clone method to install a good operating system is likely to occur in this way or that way, then these are cloned computer in practical work process is prone to the phenomenon of instability, the network connection is not stable phenomena, of course, also belongs to this class of problems within. Therefore, when we were in peacetime on the Internet, if you are experiencing frequent network disconnection failure, may wish to try through conventional methods to troubleshoot the network connection failure reason, if according to this method can't find obvious cause of the failure, then we should consider reinstalling your operating system, which tend to be not significant network fails to clear all. Transceiver start unit is through LAN fiber transceivers, routers, switches and other network devices are connected to fiber-optic lines, and local telecommunications sector directly interconnected. The last few days, click the workstations in the LANBetween the access, the connection speed is fine as long as you access the Internet network to go out, we'll find network connection speed significantly slower.　　Came across this network communication failure, I believe that most of the local area network of export network equipment or fiber-optic lines, see fiber transceivers, router both network device, I see them displayed as normal. In order to accurately locate network connection failure, the author of the first router devices and optical fiber transceiver device to disconnect, and then one network is configured properly and running very good. Laptops direct access to the optical fiber transceiver device, and then in the notebook computer attempts to access the Internet, I found the results to a single host in the form of direct access to the Internet network is not successful, this indicates that the network connection failures and router device-independent, and very likely and fiber-optic lines or optical fiber transceiver. What is optical fiber transceiver is damaged, or connect LAN broadband fiber optic lines out of the question?, I call a local telecommunications sector technicians, ask them to help test the fiber-optic lines is a shorted or ruptures, but professional and technical personnel of the technical tests revealed that the fibre line is connected, it further affirmed that network failure is caused by the optical fiber transceiver. But Media Converter generally accept the processing of data signals are weak signal, the device does not have a specific reason is not very easy to be damaged. Then I remembered the units in the last few days the AC input voltage instability, has been part of the electrical equipment have accidentally burned, so I doubt the converter without UPS power protection, is likely to be an unstable input power supply shocks. When you try to apply optical fiber transceiver device off, the whole all workstations in the LAN and are able to access Internet network, and thus the entire LAN does not have access to the Internet's fault had been completely ruled out. From this network trouble shooting process we future once using conventional methods to troubleshoot the internal network, did not find any problems, we must broaden the analysis of ideas, and receiving from the network connections section, to gradually eliminate the transceiver to the specific cause of the failure in part, not only to look at network, otherwise easily solve network problems during the walk several detours connector to start a government building LAN is 100 Gigabit Desktop, Gigabit backbone network topology, LAN-to-use master switch is a CISCO Catalyst 3550 model of brand products, L2 switch all using Bay Company products. In actual operation, we sometimes see the main switch and part of the secondary network traffic between switches are not working properly, causing many station cannot be stable Internet access. Came across this network failure, most cases are optical transceiver modules is experiencing a problem, usually as long as the optical fiber transceiver modules replace or swap out the interface, you can turn off the network fault elimination. If this method does not add the network fault elimination, there is another way we try, it is the master switches over to the faulty optic head and there is no fault of the fiber head into groups for a swap, and let the module stays, this might be able to receive the miraculous. Exchange Connector to crack because some network problems, mainly the network communication process is relatively complex, and the runtime environment is constantly evolving, so many communication failures are not necessarily physical failure, change the connection connector can sometimes give unexpected results.