Monitoring Redundant SCGs

You monitor and maintain redundant SONET Clock Generators (SCGs) installed in the T320 router and the T640 routing node to ensure that there is no interruption of function. SCGs provide a clock signal for SONET/SDH, and select a clock signal from any Flexible PIC Concentrator (FPC), or from the external clock inputs.

Table 117 lists the tasks you perform to monitor redundant SCGs.

Table 117: Checklist for Monitoring the Redundant SCG

Monitor SCG Tasks	Command or Action
Understanding Redundant SCGs
Displaying Redundant SCG Hardware Information	show chassis hardware
Monitoring Redundant SCG Status
Monitor the Redundant SCG Environmental Status	show chassis environment show chassis environment scg
Display the Redundant SCG LED States at the Command Line	show chassis craft-interface
View the Redundant SCG LEDs	Remove the rear component cover and look on the SCG faceplate at the back of the T320 router or T640 routing node chassis.
Displaying Redundant SCG Mastership
Display the SCG Master and Standby from the Craft Interface Output	show chassis craft-interface
View the SCG LEDs	Remove the rear component cover and look on the SCG faceplate at the rear of the T320 router or T640 routing node chassis.
Performing a Swap Test on a Redundant SCG	Take the SCG offline. request chassis scg offline slot number Replace the SCG with one that you know works. Bring the SCG online. request chassis scg offline slot number Verify the SCG status. request chassis scg offline slot number
Returning the SCG	See Return the Failed Component, or follow the procedure in the M40e or M160 router hardware guide.