Smooth troubleshooting of vswitches and vrouters

Source: Internet
Author: User

Vswitches and vrouters are still commonly used. So I studied how to solve the problem of vswitches and vrouters. Here I will share with you, hoping to help you. I first asked about the network conditions of my friend's organization, which has two floors. I used to use a four-Port Express Broadband Router to share the Internet. There was only one machine on the second floor, use a network cable pulled from a router on the first floor to directly connect to the Internet.

Now, with machines added, a vswitch and vro are also required on the second floor to provide multi-host internet access, in addition, the original four-Port Express routers are directly upgraded to an eight-port tengda Broadband Router to facilitate the access of more machines. I thought it should be very simple. I just needed to set up a new vro and connect the vswitch and vro on the second floor. So I readily agreed and decided to give it to him over the weekend. After arriving at a friend's organization on weekends, I soon set up a new router and connected all the computers on the first floor to the Internet, then I took an eight-port 10/100 M switch of the Tp-link they had bought and went upstairs. I thought the connection should be OK. A problem occurred! After all the network cables are connected, the computers on the second floor can access each other, but the computers on the first floor, including routers, cannot access the Internet. Where is the problem? From the fault perspective, there should be a problem between the vswitch on the second floor and the Broadband Router on the first floor. In order to eliminate the problem of the router port connected to the vswitch, I tried to connect the vswitch to different ports on the vro, but the fault still persists.

Because the vswitch and the vro are connected to the vro through the UPLINK port, I suspect that the up-link port of the vswitch is faulty. Therefore, the vswitch obtains the following information, find the root network cable, connect the UP-LINK port to the vro, and then connect a computer to the vswitch. The Internet access is completely normal, indicating that the up-link port of the vswitch and the vro is normal. Is there a problem with the network cable connected to the building? Can I use this network cable to access the Internet normally? Because there is no tester and the network cable is buried in the wall, you cannot perform a careful test on the network cable. However, if you connect the network cable to a computer, the computer can immediately access the internet. No problem with the network cable?

No problem with the vswitch, no problem with the vro, no problem with the network cable, but the vswitch and the vro cannot be connected. At this point, the problem seems to be in a dead state. Is the network cable on the second floor too long to exceed the Ethernet limit? The length of the network cable between two floors is less than 50 meters. Shouldn't it be possible to connect directly to the computer to access the Internet? I can't help but check the Network Properties of the computer on the second floor. I hope to find some clues and find that all their network cards are 10 m. I seem to have some thoughts, but I cannot grasp them after careful consideration. The vswitch and vro are both 10 M/M Adaptive and should not be unable to connect due to speed problems. Seeing that the sky is going to be late, I had to give up for the moment and let them use it first. Wait for me to find a solution.

The next day, I decided to post the problem on the IT network forum and ask about the solution. enthusiastic netizens proposed two ideas: First, check that UPLINK ports and other ports share ports, there may be port contention issues, and there may be problems with the crystal head. I have considered port contention during the test. I tried to connect only one machine and change too many ports. Therefore, I should be able to eliminate the problem of at least the crystal head. If there is a problem with the crystal head, should I still be unable to connect to the computer? The problem is that a network cable can connect to a computer but cannot connect to a switch. When I re-summarized the problem to a netizen, my mind suddenly flashed. By the way, I could connect to a computer but could not connect to a switch. What is the difference between a computer and a switch? The vswitch ports are 100/10 M Adaptive, while the computer Nic is 10 M. A computer NIC that can be connected to 10 M cannot be connected to a M vswitch, the problem may be caused by the speed of the network cable.

Since the Unit cabling time of a friend was earlier, 10 M Ethernet was popular at that time. Therefore, the network cable buried in the wall may be 10 m. Because the vro is a 10/100 M Adaptive port, when connected to the computer upstairs, the peer is found to be a 10 M Nic, The vro will set the port to 10 M communication mode, so the network cable can be used normally. However, when a vswitch is connected, because the vswitch and the vro are also 10/100 M Adaptive ports, the vro will find that the Peer end is a M device, so the M speed communication mode is adopted, at this time, the 10 m network cable cannot be used, so the switch and the router are unable to communicate. Yes, it must be. I immediately rummaged through the Cabinet and found a 10 m old hub. The next day, I rushed to my friend's unit and changed the M switch on the second floor to a 10 m hub. Then I connected the computer. Haha, I finally got through.

Looking back at the problem solving process, we were lost because we couldn't find the cause of the problem when we found that every device seemed to be okay. In fact, communication is normal, and it is the result of a reasonable combination of different devices. It is normal for devices that do not match to work collaboratively, by carefully analyzing the similarities and differences between the results of various tests, you can quickly locate the cause of the problem.

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