Step 1: Locate Loss of Signal and Loss of Frame Alarms

Purpose

A loss of signal (LOS) or loss of frame (LOF) alarm indicates that a signal could not be detected at the T3 interface.

Action

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 6, the X indicates that there is a connection problem between Router2 and the nearest T3 network element.

Figure 6: 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...]

What It Means

The sample output shows that Router2 (Rx) detected a cumulative LOS and LOF for 273 seconds. The defect was declared twice during that time.