21-6Configuring System DebuggingOutput of the debugging information may reduce system efficiency. The debugging commands areusually used by administrators in diagnosing network failure. After completing the debugging, disablethe corresponding debugging function, or use the undo debugging all command to disable all thedebugging functions.Output of debugging information is related to the configurations of the information center and thedebugging commands of each protocol and functional module. Displaying the debugging informationon a terminal (including console or VTY) is a common way to output debugging information. You canalso output debugging information to other destinations. For the detailed configurations, refer toInformation Center Commands in the System Volume. By default, you can output debugginginformation to a terminal by following these steps:To do… Use the command… RemarksEnable the terminal monitoringof system information terminal monitorOptionalThe terminal monitoring on theconsole is enabled by defaultand that on the monitoringterminal is disabled by default.Available in user viewEnable the terminal display ofdebugging information terminal debuggingRequiredDisabled by defaultAvailable in user viewEnable debugging for aspecified moduledebugging { all [ timeouttime ] | module-name[ option ] }RequiredDisabled by defaultAvailable in user viewDisplay the enabled debuggingfunctionsdisplay debugging [ interfaceinterface-typeinterface-number ][ module-name ]OptionalAvailable in any viewYou must configure the debugging, terminal debugging and terminal monitor commands first todisplay the detailed debugging information on the terminal. For the detailed description on theterminal debugging and terminal monitor commands, refer to Information Center Commands in theSystem Volume.Ping and Tracert Configuration ExampleNetwork requirementsAs shown in Figure 21-4, Device A failed to telnet Device C. Now it is required to determine whether anavailable route exists between Device A and Device C. If no such a route exists, you need to locate thefailed nodes in the network.
