Cisco NCS 1010 Optical Applications Configuration Guide, IOS XR Release 25.x.x

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Optical Time Domain Reflectometer

Updated: February 5, 2026

Overview

This chapter explains how to utilize integrated fiber diagnostic tools to monitor link performance and localize faults in real time. It covers configuring scan parameters, managing baseline references, and analyzing measurement data to ensure network integrity and streamline troubleshooting processes.

Table 1. Feature History
Feature Name Release Information Feature Description

OTDR enhancements

Cisco IOS XR Release 25.4.1

These enhancements have been made to OTDR functionality:

  • OTDR results now include total measured loss and total measured length alongside existing measurements.

  • Unique names can be assigned to SOR files for easier identification.

  • SOR files from automatic and manual OTDR scans are organized into separate folders to differentiate between file types.

CLI:

The keyword label string is added to the command otdr-start controller ots R/S/I/P direction.

    Fiber link monitoring and diagnostics using OTDR

    This topic explains how Optical Time Domain Reflectometers (OTDRs) are used for real-time monitoring and diagnostics of fiber optic links, highlighting their ability to measure loss, reflectance, and detect defects to ensure optimal fiber network performance.

    Automatic OTDR scans

    This topic explains how automatic OTDR scans function as a fiber diagnostics feature, automatically triggering OTDR tests in response to events such as span faults and restorations. It also describes bidirectional scanning capabilities for comprehensive fault detection and rapid fault localization through alarm monitoring.