Related Documentation
- M, T Series
- List of Common SONET Alarms and Errors
- Displaying SONET Alarms and Errors
- Locating Most Common SONET Alarms and Errors
- Locating Loss of Signal Alarms
- Locating Alarm Indication Signal Alarms
- Locating Remote Defect Indication Alarms
- Locating Remote Error Indication Line Errors
- Locating Bit Error Rate Alarms
- Locating Payload Label Mismatch Path Alarms
- Locating Loss of Pointer Path Alarms
- Locating Unequipped Payload Alarms
- Locating Phase Lock Loop Alarms
Locating Alarm Indication Signal Alarms
An alarm indication signal (AIS) is sent downstream to signal an error condition. There are two types of AIS alarms:
- Alarm indication signal path (AIS-P) is sent by an LTE to a downstream PTE when an LOS or LOF is detected on a upstream SONET section.
- Alarm indication signal line (AIS-L) is sent by an STE to a downstream LTE when an LOS or LOF is detected on an incoming SONET section.
- Example of a Router Receiving Only an AIS-P Alarm
- Example of a Router Receiving Both an AIS-L and AIS-P Alarm
Example of a Router Receiving Only an AIS-P Alarm
Problem
Figure 1 shows a router receiving only an AIS-P alarm. The X indicates that the LOS or LOF occurs in the section between Router 1 and Repeater 1.
Solution
All diagnostics are from the perspective of Router 2 (the Juniper Networks router).
Figure 1: Example of a Router Receiving Only an AIS-P Alarm
Meaning
In Figure 1, the progression of events occurring after the failure is as follows:
- Repeater 1 detects an LOS or LOF on an incoming SONET section.
- Repeater 1 sends an AIS-L downstream to ADM1 (LTE).
- ADM 1 sends an AIS-P to Router 2 (PTE).
- The only alarm that Router 2 receives is the AIS-P alarm from ADM 1.
Example of a Router Receiving Both an AIS-L and AIS-P Alarm
Problem
Figure 2 shows a router receiving both an IS-L and AIS-P Alarm. The X indicates that the LOS or LOF occurs in the section between ADM 2 and Repeater 2.
Solution
All diagnostics are from the perspective of Router 2 (the Juniper Networks router).
Figure 2: Example of a Router Receiving Both an AIS-L and an AIS-P Alarm
What It Means
In Figure 2, the progression of events occurring after the failure is as follows:
- Repeater 2 detects an LOS or LOF on the incoming section.
- Repeater 2 sends an AIS-L and AIS-P downstream to Router 2.
- Router 2 receives both an AIS-L and an AIS-P from Repeater 2.
Related Documentation
- M, T Series
- List of Common SONET Alarms and Errors
- Displaying SONET Alarms and Errors
- Locating Most Common SONET Alarms and Errors
- Locating Loss of Signal Alarms
- Locating Alarm Indication Signal Alarms
- Locating Remote Defect Indication Alarms
- Locating Remote Error Indication Line Errors
- Locating Bit Error Rate Alarms
- Locating Payload Label Mismatch Path Alarms
- Locating Loss of Pointer Path Alarms
- Locating Unequipped Payload Alarms
- Locating Phase Lock Loop Alarms
Published: 2012-12-10
Related Documentation
- M, T Series
- List of Common SONET Alarms and Errors
- Displaying SONET Alarms and Errors
- Locating Most Common SONET Alarms and Errors
- Locating Loss of Signal Alarms
- Locating Alarm Indication Signal Alarms
- Locating Remote Defect Indication Alarms
- Locating Remote Error Indication Line Errors
- Locating Bit Error Rate Alarms
- Locating Payload Label Mismatch Path Alarms
- Locating Loss of Pointer Path Alarms
- Locating Unequipped Payload Alarms
- Locating Phase Lock Loop Alarms
