Cause of Cisco router crash

No one liked this, but sooner or later there would be a router crash. All that should be done now is to save the key information in the router memory so as to identify the cause of the router crash and prevent this situation from happening again. To do this, you need to configure the vro to save the core dump information stored on the vro at the time of crash. Next, I will tell you what is the core dump information, what is its usefulness, and how to save these files that are very important for Accident Analysis on the vro.

What is the core dump information?

The core dump information refers to a complete image copy of The vro memory information. When a system crash or unrecoverable error occurs on the vro, all information in the memory is written into the memory of the server for convenience of reloading. Saving a core dump is very important for identifying possible causes of system crashes. Core Dump information does not support personal analysis. It requires technical support from Cisco technical assistance center TAC. When a router crash occurs, you need to open a connection to the technical assistance center and send the obtained information to trained staff. Remember that the core dump information must be saved when the router crashes. After the vro is restarted, such core dump information does not exist.

Important troubleshooting commands used when a router crashes

Before learning how to configure the core dump information, let's take a look at some important commands for troubleshooting the router crash:

Show version): This command displays available information about the hardware configuration, Cisco Internet operating system version, memory, and interfaces of the router. It may be a hardware error that causes the router to crash. This information can also help you understand the vro Running code version and the number of available memory and flash memory.

Display stack show stacks): this is also a very useful command that can be used to monitor the use process and Interrupt Routine of the stack. This command displays information when a similar bus error occurs or a software crash occurs.

Show context): This command can save information such as the reason for restarting the system and stack trace information.

In addition to core dump information, Cisco's technical assistance center may also ask you to provide information displayed by the show tech-support Command. This command displays configuration, statistics, and other information and logs on to the vro.

For more information about these commands, see the Cisco website.

Set Cisco Internet Operating System to save core dump Information

Cisco Internet Operating Systems can save or transmit a core dump file in four different ways. They are:

File Transfer Protocol FTP)

Remote replication protocol (RCP)

Ordinary transmission protocol (TFTP)

The flash drive is stored on the vro instead of transmitted over the network)

We usually recommend that you use the File Transfer Protocol FTP). Therefore, this article will provide the configuration in this case. By the way, whether you are using FTP, RCP, or any other method described above, make sure that the protocol works properly before creating the core dump file. In other words, before using this mode, perform a test to ensure that the system runs normally. For example, you can use the configuration of the replication router to set the server that saves the core dump file to test whether the file transfer protocol runs reliably:

Router # copy running-config ftp

Because the core dump file is not restarted, You need to manually create the core dump file. In Global mode, enter the following command:

Router # write core

This command is useful when the vro fails rather than crashes. Note that it will dump all the information in the memory, not just the information being used. Therefore, ensure that there is sufficient memory to accept the relevant information. In addition, I do not recommend performing this operation on the running vro.

The following is an example of the command used to perform core dump using the file transfer protocol:

Ip ftp username: Set the user's FTP connection.

Ip ftp password: Set the user's FTP connection password.

Exception protocol ftp: sets the file transfer protocol for core dump.

Exception region-size 65536: configure the size of the storage area.

Exception dump ip-address: Set the network ip address of the server to which the core dump is transferred when the router crashes.

Cisco recommends that the router be directly connected to the FTP server without any type of transit.

The debug sanity command is also useful for debugging memory errors, especially for input/output memory. You may use this command when you work with Cisco technical representatives. Let's take a look at the output result of a core dump file using the show version command. Note that the error message is located at the bottom of the Output Message.

Router # show version Cisco Internetwork Operating System SoftwareIOS (tm) RSP Software (RSP-PV-M), Version 12.0 (10.6) ST, early deploymentmaintenance interim SOFTWARECopyright (c) 1986-2000 by cisco Systems, inc. compiled Fri 23-Jun-00 by richvImage text-base: 0x60010908, data-base: 0x60D96000ROM: System Bootstrap, Version 12.0 (19990806: 174725), development softwarebootflash: RSP Software (RSP-BOOT-M ), version 12.0 (9) S, early deploymentrelease software (fc1) Router uptime is 20 hours, 56 minutes

In the event of an accident, another file that will help you is the crashinfo file. It is stored in the Start flash or flash. For more information about the crashinfo file, visit the Cisco website.

Conclusion

The core dump configuration is stored on each vro. Therefore, it is very important to identify the cause by using the core dump information that can be found once the vro crashes. If the core dump information is not saved, it cannot be found once the vro has been restarted. By setting the core dump file, with the help of Cisco's technical assistance center, you can solve the problem at the first time of the router crash.

For more information about the Core dump, visit the Cisco website's "Creating Core Dumps" and "Troubleshooting Router Crashes ."