A.WDM side outer loopback

B.Client side outer loopback

C.WDM side inner loopback

D.Client side loopback

A.Optical power verification

B.Fiber connection verification

C.Subrack verification

D.Board Verification

A.Cascading mode

B.Cascade Mode

C.Overlapping Mode

D.Nested Mode

A.ODU4

B.ODU1

C.ODU3

D.ODU2

A.When the number of errors in the PM segment of the ODU layer exceeds the limit, the number of errors exceeds the specified error threshold.

B.When the PM segment of the ODU layer is degraded by bit errors, and the number of error codes exceeds the specified bit error degradation threshold

C.The error error of the ODUkTCMn layer exceeds the limit, and the number of error errors exceeds the specified error degradation threshold.

D.The ODUkTCMng signal is degraded, and the number of bit errors exceeds the specified error threshold.