65The output shows that Device A can reach Device B but cannot reach Device C. An error hasoccurred on the connection between Device B and Device C.5. Use the debugging ip icmp command on Device A and Device C to verify that they can send andreceive the specific ICMP packets.Or use the display ip routing-table command to verify that there is a route from Device A to DeviceC.System debuggingThe device supports debugging for the majority of protocols and features, and provides debugginginformation to help users diagnose errors.Debugging information control switchesThe following switches control the display of debugging information:• Module debugging switch—Controls whether to generate the module-specific debugginginformation.• Screen output switch—Controls whether to display the debugging information on a certain screen.Use terminal monitor and terminal logging level commands to turn on the screen output switch. Formore information about these two commands, see Network Management and MonitoringCommand Reference.As shown in Figure 4, assume that the device can provide debugging for the three modules 1, 2, and 3.The debugging information can be output on a terminal only when both the module debugging switchand the screen output switch are turned on.Debugging information is typically displayed on a console. You can also send debugging information toother destinations. For more information, see "Configuring the information center."Figure 4 Relationship between the module and screen output switch
