Example of a Router Receiving Only an AIS-P Alarm

In Figure 15, the X indicates that the LOS or LOF occurs in the section between Router1 and Repeater1.

All diagnostics are from the perspective of Router2 (the Juniper Networks router).

Figure 15: Example of a Router Receiving Only an AIS-P Alarm

What It Means

In Figure 15, the progression of events occurring after the failure is as follows:

1. Repeater1 detects an LOS or LOF on an incoming SONET section.
2. Repeater1 sends an AIS-L downstream to ADM1 (LTE).
3. ADM1 sends an AIS-P to Router2 (PTE).
4. The only alarm that Router2 receives is the AIS-P alarm from ADM1.