Alarm Configuring and Monitoring Guide, Cisco IOS XE 17 (ASR 920 Series Routers)

Alarms

This chapter provides information about alarms supported for SONET and SDH, and their maintenance.

Alarms are triggered when a component fails or does not perform as expected. Alarms are triggered by the chassis.

Alarms can be defined using the following two terms:

Alarm State—It is the state the chassis enters when a certain event occurs. For example, the state of the chassis when the ambient temperature is beyond the specified limits.
Alarm Indication—It is a visual signal to indicate the alarm state. For example, the TEMP LED glows red if the ambient temperature is beyond the specified limits, and it turns green if the ambient temperature is within specified limits.

Typically, a failure condition detected by a chassis results in one or more error conditions sent both upstream and downstream on the network.
- Alarm Indication Signal (AIS)—AIS alarms are reported downstream from a detecting device, and to prevent consequential downstream failures or alarms from being raised.
- Remote Defect Indicator (RDI)—RDI alarms are always reported upstream from the detecting device.

Note

Even when the controller is in the down state with alarms, the cross connection between the controllers is up.

Restrictions for Alarms

In T3, an AIS alarm is supported only in the framed mode and not supported in the unframed mode.

The following table lists the types and sub types of SDH Alarms.

Table 1. SDH Supported Alarms
Alarm Type	Sub Alarm Type
Section Alarms	LOS — Loss of Signal LOF — Loss of Frame RS-BIP — Bit Interleaved Parity
Line Alarms	MS-BIP — Multiplex Section-Bit Interleaved Parity MS-REI — Multiplex Section-Remote Error Indication MS-AIS — Multiplex Section-Alarm Indication Signal MS-RDI — Multiplex Section-Remote Defect Indication AU-AIS — Administrative Unit-Alarm Indication Signal AU-LOP — Administrative Unit-Loss of Pointer
STS Path Alarms	HP-UNEQ — High order Path-Unequipped HP-PLM — High order Path-Payload Label Mismatch HP-RDI — High order Path-Remote Defect Indication HP-BIP — High order Path-Bit Interleaved Parity HP-REI — High order Path-Remote Error Indication TU-LOM — Tributary Unit-Loss of Multiframe TU-AIS — Tributary Unit-Alarm Indication Signal TU-LOP — Tributary Unit-Loss of Pointer
VT Path Alarms	LP-UNEQ — Low order Path-Unequipped LP-PLM — Low order Path-Payload Label Mismatch LP-RDI — Low order Path-Remote Defect Indication LP-RFI — Low order Path-Remote Failure Indication LP-BIP — Low order Path-Bit Interleaved Parity LP-REI — Low order Path-Remote Error Indication

Note

TIM alarms are not supported.