Example of Both REI-L and REI-P Counters Incrementing

In Figure 20, the wavy line indicates that there is a line error in the section between Repeater2 and Router2.

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

Figure 20: Example of a Router Receiving Both An REI-L and REI-P Counter Incrementing

What It Means

In Figure 20, the progression of events occurring after the failure is as follows:

1. Repeater2 detects some parity errors in the B1 byte from a corrupted SONET frame.
2. ADM2 detects parity errors in the B2 byte.
3. ADM2 sends an REI-L upstream to Router2.
4. Router1 detects parity errors in the B3 byte.
5. Router1 sends back an REI-P upstream to Router2.
6. Router2 sees incrementing REI-L and REI-P errors.