Analysis of improper switch installation faults and solutions (1)

Improper switch installation failure analysis and solutions, preliminary analysis of improper switch installation failure, irrelevant to the server. Locate the faulty source of vswitch installation. The problem lies in a vswitch. perform data tests to analyze the faulty vswitch installation.

A vswitch is a key connection device in a LAN. It has a large number of vswitches in a LAN. In such a network environment, the administrator needs to reasonably deploy the vswitch based on its performance and characteristics, because your improper deployment will pose hidden risks in the later network O & M. I would like to share with you a case of network failure caused by improper switch installation location.

Improper switch installation and Failure

The computer room in a middle school encountered a very strange switch installation failure in a computer test simulation test: when students are doing a simulated test, client computers frequently experience network interruptions with servers. However, in case of an improper switch installation failure, each client can PING the server with a latency of less than 10 ms.

The server is not visible from the network neighbors, and every client computer can access each other through the network neighbors when a fault occurs. Because the final simulated examination file of the student must be stored on the server after being operated on the local machine, this failure causes the simulated examination to fail.

Preliminary Analysis of improper switch installation faults, irrelevant to the server

After observation, it is found that the solution for improper switch installation and failure occurs when the number of students accessing the server increases. as a result, the fault point is located on the server at the beginning, and the number of connections on the server may be incorrect. When the server is installed, the number of connections is set to 999, while the number of connections of servers working in other data centers is set to 256. Is the failure caused by excessive connections? So we reduced the number of connections to 512 and 256 in sequence, and the Failure remained after the server was restarted. Based on the experiment results, the failure assumption caused by the number of connections setting is excluded.

The IBMX3600 server is newly purchased, so it is suspected that the fault is caused by a conflict between the new device and the installed examination system. So I immediately moved to another backup server, IBMX236, which can be used normally in another laboratory. However, when I switched to the backup server, the fault remained. So far, it is preliminarily determined that the fault has nothing to do with the server.

Locate the faulty source for improper switch installation. The problem lies in one switch.

So where exactly is the problem? In this lan, there are only three types of devices except Network cables: computers, servers, and switches. Based on tests that have been performed, the client computer and server faults have been ruled out. If the PING command is successful, the network cable is correct. Therefore, consider whether the fault is caused by a switch. Two types of switches are in use in the lab, namely, the netshitong DCS 2026 and H3C S1024R Switches of Digital China.

In order to determine the improper installation failure of the switch, 20 client computers and IBMX3600 servers in the laboratory are connected to one switch. First, the H3C S1024R switch was tested. When 20 client computers are connected to the server by pinging the server for a long time, the test questions are stored on the server. If the switch is improperly installed, no fault occurs. Then, the 20 computers were connected to the DCS 2026 switch. When 15th client computers were stored on the server, the switch was improperly installed to reproduce the fault, it is preliminarily determined that the cause of the improper installation of the switch is the switch.

Perform data testing to analyze vswitch installation failures.

Why does a switch of DCS 2026 cause improper installation of network switches? We decided to conduct a data test. In order to make the test result more appealing, we found a 3rd switch from CISCO, a 355 manufacturer, to perform a test in the same environment. During the test, the connection environment remains unchanged. All three types of switches use the factory default settings. A file with a size of MB is prepared on each client computer.

After 20 computers are connected to shenzhou.com DCS 2026, H3C S1024R, and CICCO3550 in turn, the 845MB files on each computer are copied to the shared folder on IBMX3600, which is displayed by the Network neighbors. The EtherPeek packet capture software is used on the server to analyze all data flowing through the ports connected to the server.