Use displaycpu commands to ensure core switch Security

The core switch is still quite common, so I have studied the displaycpu command details in the switch. Here I will share it with you and hope it will be useful to you. In the LAN operating environment, the working status of core switch equipment is extremely important. It directly affects the efficient and stable operation of LAN networks. When a fault occurs in a LAN, the network administrator should learn to find the cause of the fault from the background management system of the core switch, which can greatly improve the network management efficiency.

This is not the case. This article uses the core switch products of the Quidway series, a mainstream product on the market, as an example to recommend some tips on how to use the display command of the core switch and efficiently manage the network, I hope this content will inspire you!

Use the displaycpu command to determine the switch card status

Currently, multiple plug-in cards are installed at the same time on core switch devices. Each plug-in card can be integrated with up to 24 optical fiber switch ports, the CPU resources of the Board plug-in card where the switch port is located may be greatly consumed. In severe cases, the Board plug-in card may be paralyzed, at this time, all the switching ports connected to the motherboard plug-in card will not work properly, so the working subnets connected to each optical fiber switching port will not be able to access the Internet normally.

Obviously, when there are multiple working subnets in the LAN that cannot access the Internet at the same time, we need to check whether the switch plug-in card is working properly. The easiest way to check and determine the switch plug-in card status is to use the displaycpu command of the switch to observe their CPU consumption rate. If you find that the CPU consumption rate of a plug-in card exceeds 50%, in this case, the data traffic on a certain switch port is very large. In this case, we need to check the traffic status of each fiber switch port in sequence and find the switch port with an exception, and temporarily disable the port so that the working status of the corresponding plug-in card on the core switch can be restored to normal. The following describes how to use the displaycpu command to view the working status of the core switch plug-in card:

Log on to the background management interface of the core switch with the system administrator account, and run the "sys" string command in the command line status of the interface to switch the working mode of the core switch to the System View Mode; enter the string command "displaycpu" and click the Enter key. The result 1 is displayed on the System screen. here we can see that several plug-ins are installed on the target core switch, CPU usage of each plug-in card in the last 5 seconds, the last minute, and the last five minutes. If the CPU usage rate in the last five minutes is found to be above 50%, it indicates that the working status of the switch plug-in card may be abnormal. At this time, we must check all the optical fiber switching ports connected to the plug-in card in order to observe the information traffic of each switch port. If the information traffic of the port is abnormal, we must use the "shutdown" command in time to disable the working status of the corresponding optical fiber switch port to avoid affecting the working status of Multiple Working subnets.

How to manage the network by using the switch Display command

Use the displayint command to check the switch port status. As mentioned above, if a plug-in card of the switch is abnormal, then we need to check the bandwidth traffic of each switch port on the card device. How can we check the traffic status of a specific optical fiber switch port? In fact, it is very simple. We can use the displayint command to complete the task. With the displayint command, we can not only view the bandwidth traffic of the specified optical fiber switch port, but also the bandwidth traffic of the ordinary Ethernet port; in addition to traffic information, this command can also view other status information of the target switching port, such as the link type, duplex mode, working speed, traffic control, and network cable type of the port.

For example, if you want to check the working status of the g0/1/23 optical fiber switch port, you can use the telnet command to log on to the background management system of the target core switch and run the "sys" string command, switch the working mode of the core switch to the global configuration mode. In this mode, enter the string command "displayintg0/1/23" and click the Enter key. The result shown in 2 is displayed on the System screen, from this we can see that the g0/1/23 optical fiber switch port is in the "up" status, and the port supports the traffic control function, using the full duplex mode, the switching port operates at 1000 mbps. You can even see the specific virtual working subnet to which the switching port is divided.

When we see that the number of input and output data packets on the target exchange port reaches more than 1000 per second in the result interface shown in figure 2, consider whether the bandwidth traffic of the switch port is abnormal, especially whether the abnormal data traffic is caused by a broadcast storm, if a broadcast storm exists in a virtual subnet, it will not take long for the whole LAN to be significantly affected. In severe cases, the whole Lan may be paralyzed. To determine whether a specified switching port has a broadcast storm, we can run "displayintg0/1/23" every second to write down the value of each output broadcast packet, compare the two values before and after. Once we see that the value of the output broadcast packet is increasing with more than 1000 packets per second, there is a broadcast storm on the exchange port, in this case, the only thing we need to do is temporarily disable the running status of the g0/1/23 optical fiber switch port to prevent the broadcast storm from affecting the working status of the entire core switch.

When you want to disable the running status of the g0/1/23 optical fiber switch port, You can execute the string command "intg0/1/23" in the global configuration status of the core switch ", switch the background management system of the core switch to the view mode of the target switch port. In this status, run the "shutdown" string command, you can temporarily change the status of the target switch port to "down". Then, the virtual working subnet connected to the switch port will not be able to access the Internet, then the broadcast storm will not affect the core switch. To solve the broadcast storm, we need to find the L2 Switch that maintains connection with the g0/1/23 optical fiber switch port and log on to the background management system of the switch, continue to use the displayint command to view the data traffic of each Ethernet switch port, so that you can find the final "Sin.