Configuration Guide for Cisco NCS 1014, IOS XR Releases 26.x.x

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Span Loss

Updated: June 18, 2026

Explains the factors that cause signal loss across fiber-optic spans, how span loss impacts network performance, and methods used to measure and manage signal degradation in optical transmission systems.

Table 1. Feature History

Feature Name

Release Information

Feature Description

Span loss measurement

Cisco IOS XR Release 25.1.1

NCS 1014 measures span loss between two nodes. The measurement is performed using the OSC links created between the nodes by configuring the OSC pluggable to be operational and OSPFv2 protocol on the EDFA2 card on the nodes. These measurements are essential during network changes, like equipment installation or fiber repairs.

You can configure both minimum and maximum span loss thresholds. If the received span loss exceeds the maximum threshold or falls below the minimum threshold, the system will trigger a SPAN-LOSS-OUT-OF-RANGE alarm.

CLI commands are:

  • optical-line-control

  • controller Ots R/S/I/P span-loss min value

  • controller Ots R/S/I/P span-loss min value

    Span loss

    This section explains the types, calculation methods, and reporting for span losses in optical networks.

    Signal span loss control

    This section explains how signal span loss control mechanisms set expected thresholds, monitor loss changes, and trigger alarms to enhance optical link reliability.