Failure Of Switch Software

- Feb 19, 2021-

    (1) System problems:

  The switch system is a combination of hardware and software. There is a refreshable read-only memory inside the switch, which stores the necessary software system for this switch. This kind of fault is also the same as our common Windows= and Linux. Due to the design at the time, there are some loopholes. When the conditions are right, it will cause the switch to be fully loaded, packet loss, and error packets. So the switch system provides methods such as Web and TFTP to download and update the system. Of course, there may be problems when upgrading the system.

  For such problems, we need to develop the habit of frequently reading the website of the equipment manufacturer. If there is a new system launch or a new patch, please update it in time.

   (2) Improper configuration:

   Beginners are not familiar with switches, or because of different switch configurations, administrators often have configuration errors when configuring switches. For example, incorrect VLAN division leads to network failure, ports are shut down faulty, and the mode configuration of the switch and network card does not match.

   This type of failure is sometimes difficult to find, and it requires a certain accumulation of experience. If you cannot ensure that there is a problem with the user's configuration, please restore the factory default configuration first, and then configure it step by step. It is best to read the explanation book before configuring, which is also one of the habits that the network administrator should develop. Each switch has a detailed installation manual, user manual, in-depth instructions for each type of module.

   As many switch manuals are written in English, users with poor English can consult the supplier’s engineers before making specific configurations.

   (3) Loss of password:

   This may have been experienced by every administrator. Once you forget the password, you can recover or reset the system password through certain steps. Some are simpler, just press a button on the switch. And some need to be solved through certain operation steps. This type of situation generally occurs when data is lost due to human forgetting or switch failure.

   (4) External factors:

Due to the existence of viruses or hacker attacks, it is possible that a host sends a large number of data packets that do not comply with the encapsulation rules to the connected port, causing the switch processor to be too busy, causing the data packets to be too late to forward, and causing buffer overflow and loss. Packet phenomenon. There is also a broadcast storm, which not only consumes a large amount of network bandwidth, but also consumes a large amount of CPU processing time. If the network is occupied by a large number of broadcast data packets for a long time, normal point-to-point communication cannot be performed normally, and the network speed will slow down or be paralyzed.

   A network card or a port failure may cause a broadcast storm. Since the switch can only divide the conflict domain, but not the broadcast domain (without dividing the VLAN), when the number of broadcast packets accounts for 30% of the total communication volume, the transmission efficiency of the network will drop significantly.

   Generally speaking, switch software failures should be more difficult to find than hardware failures. To solve the problem, it may not cost too much money, but more time. It is best to develop the habit of keeping logs in daily work. Whenever a failure occurs, timely record the failure phenomenon, the failure analysis process, the failure resolution plan, and the failure classification summary to accumulate your own experience. For example, sometimes during configuration, due to various reasons, there was no impact on the network or no problems were found at the time, but the problems may gradually appear after a few days. If there is a log record, you can think of whether there is something wrong with the configuration of the previous few days. Since this point is often overlooked, I feel that there are problems in other areas. After many detours, I find the problem. Therefore, it is necessary to keep logs and protect information.