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Locate Loss of Signal and Loss of Frame Alarms
Problem
A loss of signal (LOS) or loss of frame (LOF) alarm indicates that a signal could not be detected at the T3 interface.
Solution
To locate the LOS or LOF alarm, check the connection between the router port and the first T3 network element. In the example network in Figure 1, the X indicates that there is a connection problem between Router 2 and the nearest T3 network element.
Figure 1: Location of an LOS or LOF Alarm in a T3 Network
 | Note: Tx represents the transmit port and Rx represents the receive port. |
Sample Output
user@router2> show interfaces t3-1/1/1 extensive[... Output truncated...]
Active alarms : LOF, LOS
Active defects : LOF, LOS
DS3 Media: Seconds Count State
PLL Lock 0 0 OK
Reframing 273 2 Defect Active
AIS 0 0 OK
LOF 273 2 Defect Active
LOS 273 2 Defect Active
[...Output truncated...]
Meaning
The sample output shows that Router 2 (Rx) detected a cumulative LOS and LOF for 273 seconds. The defect was declared twice during that time.
