Diagnostic information in the CLI 754 Go to NNCLI via serial interface.5 Enable action mode.enable6 Run the external loopback test.stack loopback-test external7 Check the results of the command. "stack loopback-test externaloutput" (page 75) shows the output from a pass and from a failure.stack loopback-test external outputPass FailExternal loopback test PASSED. External loopback test FAILED. Your stack cablemight be damaged.—End—Stack monitorThe Stack Monitor uses a set of control values to enable its operation, toset the expected stack size, and to control the frequency of trap sending.The stack monitor, if enabled, detects problems with the units in the stackand sends a trap.The stack monitor sends a trap for the following events.• The number of units in stack changes.• The trap sending timer expires.Each time the number of units in a stack changes, the trap sending timerresets and the stack monitor compares the current number of stack unitswith the configured number of stack units. If it is not equal, the switch sendsa trap and logs a message to syslog. The stack monitor sends traps froma standalone unit or the base unit of the stack.When the trap sending timer reaches the configured number of seconds atwhich traps are sent, the switch sends a trap and logs a message to syslogand restarts the trap sending timer. The syslog message is not repeatedunless the stack configuration changes. This prevents the log being filledwith stack configuration messages.When you enable the stack monitor on a stack, the stack monitor capturescurrent stack size and uses it as the expected stack size. You can choose adifferent value and set it after enabling the feature.Nortel Ethernet Routing Switch 5500 SeriesConfiguration - System MonitoringNN47200-505 03.01 Standard5.1 27 August 2007Copyright © 2005 - 2007, Nortel Networks.