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.

  • When the T3 RAI alarm is asserted, the propagation of the RAI alarm is stopped on the T1 interface.

    This behaviour is applicable for the following interface modules:

    • A900-IMA48T-C

    • A900-IMA3G-IMSG

    • A900-IMA1Z8S-CXMS

    • A900-IMA1Z8S-CX

SONET Alarms

Alarms at SONET Layers

SONET equipment detects events and alarms at each of the three layers — section, line and path. A SONET chassis sends alarms in both upstream and downstream directions in order to notify other devices of the problem condition.

The interface of an active alarm or defect is maintained in a down/down state. The process used to troubleshoot down/down SONET interfaces is similar to that of digital interfaces, such as T1 and T3.

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

Table 1. SONET Supported Alarms

Alarm Type

Sub Alarm Type

Section Alarms

  • LOS — Loss of Signal

  • LOF — Loss of Frame

  • SEF — Severely Error Frame

Line Alarms

  • AIS-L — Line AIS

  • REI-L — Line Remote Error Indication

  • RDI-L — Line Remote Defect Indication

  • B2 — Line BIP Error (SF/SD)

  • TCA for B2

Path Alarms

  • AIS-P — STS Path AIS

  • LOP-P — STS Path Loss of Pointer

  • B3 (SF/SD) — STS Path BIP Error

  • UNEQ-P — STS Path unequipped

  • REI-P — STS Path Remote Error

  • RDI-P — STS Path Remote Defect Indication

  • PLM-P — STS path Payload Label Mismatch

  • LOM — Loss of MultiFrame

  • TCA for B3

VT Alarms

  • AIS-V — VT Path AIS

  • LOP-V — VT Loss of Pointer

  • V-BIP (SF/SD) — VT Path BIP error

  • UNEQ-V — VT Path Unequipped

  • REI-V — VT Path Remote Error

  • RDI-V — VT Path Remote Defect Indication

  • PLM-V — VT path Payload Label Mismatch

  • TCA for VT Level BIP

T1 Alarms

  • LOS — DS1/E1 Line loss of Signal

  • AIS — DS1/E1 Path Alarm Indication Signal

  • AIS-CI — DS1/E1 Path Alarm Indication Signal Customer Installation

  • LOF — DS1/E1 Path Loss of Frame

  • RDI/RAI — Remote Defect Indication or Remote Alarm Indication

  • RAI-CI — Remote Alarm Indication Customer Installation

  • TCA for Line and Path DS1

T3 Alarms

  • LOS — DS3/E3 Line Loss of Signal

  • OOF — DS3/E3 Path Loss of Frame

  • SEF — DS3/E3 Path Severely Errored Frame

  • AIS — DS3/E3 Path Alarm Indication Signal

  • SEF/AIS-FE — Far End SEF/AIS

  • TCA for Line and Path DS3

SONET Alarms for APS

Table 2. Feature History
Feature Name Release Information Description

SONET Alarms for APS

 Cisco IOS XE 17.15.1

In APS scenarios, the existing SONET alarms follow the GR-253 standard for alarm soaking. This standardization helps filter out transient conditions by defining specific assertion and clearing times for alarms.

SONET APS Alarm Compliance Standard

On APS ports, SONET section and line alarms adhere to the GR-253 compliance standard for alarm soaking, ensuring high reliability and consistent performance across your network. These alarms incorporate a soaking period with an assertion time of 2.5 seconds and a clearing time of 10 seconds, effectively filtering out transient conditions. This reduces the incidence of false alarms and allows for more precise monitoring of network stab

APS Alarms and Conditions

Table 3. Feature History
Feature Name Release Information Description

New APS Alarms and Conditions

 Cisco IOS XE 17.15.1

New APS alarms and conditions have been introduced to enhance network monitoring and management. These alarms are raised or cleared during APS manual, forced, and lockout switch actions, providing real-time alerts on network changes. This advanced alerting mechanism ensures that network operators are immediately informed of any alterations, enabling them to swiftly respond to and manage network conditions, thereby maintaining optimal performance and reliability.

APS Alarms

New alarms for APS channel mismatch and APS mode mismatch have been introduced to enhance network monitoring and troubleshooting capabilities.

The following table details the triggering actions and the corresponding responses required to address these alarms:

Alarm

Triggering Action

What You Should Do?

K1BYTE_APS_CHANNEL_MISMATCH

Triggers an alarm for an APS channel mismatch, indicating a configuration discrepancy.

The configuration on both Customer Edge (CE) and Provider Edge (PE) routers must be identical. It is important to verify that the settings and parameters are consistent across both routers. This includes APS settings, interface configurations, and protocol parameters. By aligning the configurations on PE and CE routers,

K2BYTE_APS_MODE_MISMATCH

Triggers an alarm for an APS mode mismatch, highlighting an inconsistency in mode settings.

The configuration on both Customer Edge (CE) and Provider Edge (PE) routers must be identical. It is important to verify that the settings and parameters are consistent across both routers. This includes APS settings, interface configurations, and protocol parameters. By aligning the configurations on PE and CE routers,

APS conditions

The APS conditions are raised based on the APS switch action commands such as manual, force and lockout that you have performed on the routers. APS conditions are typically used during maintenance activities or when a specific path needs to be reserved, ensuring that traffic does not inadvertently switch to the protected path, thereby maintaining network stability.

  • Manual—Manually switches the traffic from active protect controller to the active controller.

  • Force—Forces the traffic to switch from active working controller to switch to protect controller.

  • Lock out—Locks the switch to protect port so that APS does not switch to protect controller for any failure on working port or IM. Prevents a working interface from switching to a protect interface.

The following table indicates the new APS conditions that have been introduced:

Conditions

What does it mean?

APS_NE_LOCKOUT_REQ

Indicates a Lockout Request at the near end of a SONET network. This condition is triggered when the local network element requests a lockout, preventing automatic switching to the protection path.

APS_FE_LOCKOUT_REQ

Indicates a Lockout Request at the far end of a SONET network.

APS_NE_FORCE_WK_REQ

Indicates a Forced Switch from the Working path at the near end of a SONET network.

APS_NE_FORCE_PR_REQ

Indicates a Forced Switch from the Protection path at the near end of a SONET network.

APS_FE_FORCE_WK_REQ

Indicates a Forced Switch from the Working path at the far end of a SONET network.

APS_FE_FORCE_PR_REQ

Indicates a Forced Switch from the Protection path at the far end of a SONET network.

APS_NE_MANUAL_WK_REQ

Indicates a Manual Switch from the Working path at the near end of a SONET network.

APS_NE_MANUAL_PR_REQ

Indicates a manual switch from the protect path at the near end of a SONET network.

APS_FE_MANUAL_WK_REQ

Indicates a far end manual switch from the working path, allowing remote user-initiated rerouting.

APS_FE_MANUAL_PR_REQ

Indicates a far end manual switch from the protect path, providing manual control over remote protection paths.

APS_FAIL_TO_SWITCH

Indicates a failure to switch to the protection path in a SONET network.

SDH Alarm

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

Table 4. 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.