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 T1 interface.

Action

To locate the LOS or LOF alarm, check the connection between the router port and the first T1 network element. In the example network in Figure 3, the X indicates that there is a connection problem between Router2 and the nearest T1 network element.

Figure 3: Location of an LOS or LOF Alarm in a T1 Network

   
NOTE: Tx represents the transmit port and Rx represents the receive port.


 

Sample Output

user@router2> show interfaces t1-1/1/1 extensive

[... Output truncated...]

DS1   alarms   : LOF, LOS

  DS1   defects  : LOF, LOS

  T1  media:            Seconds        Count  State

    SEF                      32            0  Defect Active

    BEE                       0            0  OK

    AIS                       0            0  OK

    LOF                      32            0  Defect Active

    LOS                      32            0  Defect Active

    YELLOW                    0            0  OK

    BPV                       0            0

    EXZ                       0            0

    LCV                       0            0

    PCV                      32        10667

    CS                        0            0

    LES                       0

    ES                       32

    SES                      32

    SEFS                     32

    BES                       0

    UAS                      32

[...Output truncated...]

What It Means

The sample output shows that Router2 (Rx) detected a cumulative LOS and LOF alarm for 32 seconds.