Optics and Hardware Configuration Guide for Cisco 8000 Series Routers

Optical configuration

Updated: June 16, 2026

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Introduces optical configuration and outlines the main concept, process, task, principle, and reference areas in this section. Guides technical users to quickly locate the procedures and supporting data they need.

Optical configuration covers optics-controller settings such as frequency, chromatic dispersion, transmit power, and host squelch behavior.

Configure frequency

Use this task to configure frequency on an optics controller.

You can select any C-band frequency from 196.1 THz to 191.3 THz, in both ITU and non-ITU channels.

Note

The 100MHz-grid keyword accepts only frequency values as user input. The 50GHz-grid keyword accepts frequency, ITU-channel, or wavelength values as user input. The Cisco IOS XR software then calculates the frequency for a given wavelength or ITU-channel.

Before you begin

Identify the optics controller optics R/S/I/P and the frequency value that you want to configure.

Procedure

	1.	Enter XR configuration mode. Example: `Router#config`
	2.	Enter optics controller configuration mode. Example: `Router(config)#controller optics 0/2/0/16`
	3.	Configure the DWDM carrier frequency. Example: `Router(config-Optics)#dwdm-carrier 100MHz-grid frequency 1921500`
	4.	Commit the configuration. Example: `Router(config-Optics)#commit`
	5.	Exit optics controller configuration mode. Example: `Router(config-Optics)#exit`
	6.	Exit XR configuration mode. Example: `Router(config)#exit`
	7.	Verify the frequency in the running configuration. Example: This example shows the running configuration: `Router#show run controller optics 0/2/0/16 Fri May 28 01:42:32.488 UTC controller Optics0/2/0/16 dwdm-carrier 100MHz-grid frequency 1921500 cd-low-threshold -5000 cd-high-threshold -5000 !`
	8.	Verify the configured frequency on the optics controller. Example: This example shows how to verify the frequency configuration: Router#show controller optics 0/2/0/16 Fri May 28 01:47:23.953 UTC Controller State: Up Transport Admin State: In Service Laser State: Off LED State: Off FEC State: FEC ENABLED Optics Status Optics Type: QSFPDD 400G ZRP DWDM carrier Info: C BAND, MSA ITU Channel=80, Frequency=192.15THz, Wavelength=1560.200nm Alarm Status: ------------- Detected Alarms: None LOS/LOL/Fault Status: Alarm Statistics: ------------- HIGH-RX-PWR = 0 LOW-RX-PWR = 0 HIGH-TX-PWR = 0 LOW-TX-PWR = 0 HIGH-LBC = 0 HIGH-DGD = 0 OOR-CD = 0 OSNR = 0 WVL-OOL = 0 MEA = 0 IMPROPER-REM = 0 TX-POWER-PROV-MISMATCH = 0 Laser Bias Current = 0.0 mA Actual TX Power = -40.00 dBm RX Power = -40.00 dBm RX Signal Power = -40.00 dBm Frequency Offset = 0 MHz Laser Temperature = 0.00 Celsius Laser Age = 0 % DAC Rate = 1x1.25 Performance Monitoring: Enable THRESHOLD VALUES ---------------- Parameter High Alarm Low Alarm High Warning Low Warning ------------------------ ---------- --------- ------------ ----------- Rx Power Threshold(dBm) 13.0 -24.0 10.0 -22.0 Tx Power Threshold(dBm) 0.0 -16.0 -2.0 -14.0 LBC Threshold(mA) 0.00 0.00 0.00 0.00 Temp. Threshold(celsius) 80.00 -5.00 75.00 0.00 Voltage Threshold(volt) 3.46 3.13 3.43 3.16 LBC High Threshold = 98 % Configured Tx Power = -10.00 dBm Configured CD High Threshold = -5000 ps/nm Configured CD lower Threshold = -5000 ps/nm Configured OSNR lower Threshold = 9.00 dB Configured DGD Higher Threshold = 80.00 ps Baud Rate = 60.1385459900 GBd Modulation Type: 16QAM Chromatic Dispersion 0 ps/nm Configured CD-MIN -26000 ps/nm CD-MAX 26000 ps/nm Second Order Polarization Mode Dispersion = 0.00 ps^2 Optical Signal to Noise Ratio = 0.00 dB Polarization Dependent Loss = 0.00 dB Polarization Change Rate = 0.00 rad/s Differential Group Delay = 0.00 ps Temperature = 21.00 Celsius Voltage = 3.42 V Transceiver Vendor Details Form Factor : QSFP-DD Optics type : QSFPDD 400G ZRP Name : CISCO-ACACIA OUI Number : 7c.b2.5c Part Number : DP04QSDD-E30-19E Rev Number : 10 Serial Number : ACA244900GN PID : QDD-400G-ZRP-S VID : ES03 Firmware Version : 161.06 Date Code(yy/mm/dd) : 20/12/08 !

The optics controller is configured with the frequency value, and the controller output shows the active frequency.

What to do next

Continue with related optical configuration tasks as required for your deployment.

Configure chromatic dispersion

Use this task to configure chromatic dispersion on an optics controller.

When you configure the maximum and minimum values for chromatic dispersion for any data rate, ensure that the minimum difference between the configured values is equal to or greater than 1000 ps/nm.

The default chromatic dispersion search ranges are:

Table 1. Default CD search range
Muxponder Rate	FEC Value	Default CD Search Range (Min-Max)
400	OFEC	-26000 to +26000
400	CFEC	-2400 to +2400
300	OFEC	-50000 to +50000
200	OFEC	-50000 to +50000
100	OFEC	-80000 to +80000

Before you begin

Identify the optics controller optics R/S/I/P and the supported chromatic dispersion range that you want to configure.

Procedure

	1.	Enter XR configuration mode. Example: `Router#configure`
	2.	Enter optics controller configuration mode. Example: `Router(config)#controller optics 0/0/0/13`
	3.	Configure the maximum chromatic dispersion value. Example: `Router(config-Optics)#cd-max 4000`
	4.	Configure the minimum chromatic dispersion value. Example: `Router(config-Optics)#cd-min -4000`
	5.	Commit the configuration. Example: `Router(config-Optics)#commit`
	6.	Exit optics controller configuration mode and XR configuration mode. Example: `Router(config-Optics)#exit Router(config)#exit`
	7.	Verify the chromatic dispersion values in the running configuration. Example: This example shows the running configuration for the optics controller: `Router#show run controller optics 0/0/0/13 Thu May 13 12:24:42.353 UTC controller Optics0/0/0/13 cd-min -4000 cd-max 4000 !`
	8.	Verify the configured chromatic dispersion values on the optics controller. Example: This example shows how to verify the configured chromatic dispersion values for the optics controller: Router#show controller optics 0/0/0/13 Controller State: Up Transport Admin State: In Service Laser State: On LED State: Green FEC State: FEC ENABLED Optics Status Optics Type: QSFPDD 400G ZR DWDM carrier Info: C BAND, MSA ITU Channel=61, Frequency=193.10THz, Wavelength=1552.524nm Alarm Status: ------------- Detected Alarms: None LOS/LOL/Fault Status: Alarm Statistics: ------------- HIGH-RX-PWR = 0 LOW-RX-PWR = 0 HIGH-TX-PWR = 0 LOW-TX-PWR = 0 HIGH-LBC = 0 HIGH-DGD = 0 OOR-CD = 0 OSNR = 35 WVL-OOL = 0 MEA = 0 IMPROPER-REM = 0 TX-POWER-PROV-MISMATCH = 0 Laser Bias Current = 0.0 % Actual TX Power = -7.87 dBm RX Power = -8.27 dBm RX Signal Power = -8.43 dBm Frequency Offset = 130 MHz Performance Monitoring: Enable THRESHOLD VALUES ---------------- Parameter High Alarm Low Alarm High Warning Low Warning ------------------------ ---------- --------- ------------ ----------- Rx Power Threshold(dBm) 1.9 -28.2 0.0 -25.0 Tx Power Threshold(dBm) 0.0 -15.0 -2.0 -16.0 LBC Threshold(mA) 0.00 0.00 0.00 0.00 Temp. Threshold(celsius) 80.00 -5.00 75.00 15.00 Voltage Threshold(volt) 3.46 3.13 3.43 3.16 LBC High Threshold = 98 % Configured Tx Power = -6.00 dBm Configured CD High Threshold = 80000 ps/nm Configured CD lower Threshold = -80000 ps/nm Configured OSNR lower Threshold = 9.00 dB Configured DGD Higher Threshold = 80.00 ps Baud Rate = 59.8437500000 GBd Modulation Type: 16QAM Chromatic Dispersion 0 ps/nm Configured CD-MIN -4000 ps/nm CD-MAX 4000 ps/nm Second Order Polarization Mode Dispersion = 5.00 ps^2 Optical Signal to Noise Ratio = 36.30 dB Polarization Dependent Loss = 0.40 dB Polarization Change Rate = 0.00 rad/s Differential Group Delay = 4.00 ps Temperature = 54.00 Celsius Voltage = 3.37 V Transceiver Vendor Details Form Factor : QSFP-DD Optics type : QSFPDD 400G ZR Name : CISCO-ACACIA OUI Number : 7c.b2.5c Part Number : DP04QSDD-E20-19E Rev Number : 10 Serial Number : ACA2447003L PID : QDD-400G-ZR-S VID : ES03 Firmware Version : 61.12 Date Code(yy/mm/dd) : 20/12/02

The optics controller is configured with the chromatic dispersion values, and the controller output shows the active CD minimum and maximum values.

What to do next

Continue with related optical configuration tasks as required for your deployment.

Configure optical transmit power

Use this task to set the transmit power of the optical signal.

Each QDD-400G-ZR-S and QDD-400G-ZRP-S optical module has its own optical transmit power range. You can change the optical transmit power value based on the module capability.

For transmit power values, see Traffic configuration values for 400G digital coherent optics.

Note

The default optical transmit power value is -10 dBm. With Tx shaping enabled, the maximum power in 1x400G, 4x100G, 3x100G, 2x100G, and 1x100G modes may be less than -10 dBm.

Before you begin

Identify the optics controller optics R/S/I/P and the supported optical transmit power value that you want to configure.

Procedure

	1.	Enter XR configuration mode. Example: `Router#config`
	2.	Enter optics controller configuration mode. Example: `Router(config)#controller optics 0/2/0/16`
	3.	Configure the optical transmit power. Example: `Router(config-Optics)#transmit-power -125`
	4.	Commit the configuration. Example: `Router(config-Optics)#commit`
	5.	Exit optics controller configuration mode. Example: `Router(config-Optics)#exit`
	6.	Exit XR configuration mode. Example: `Router(config)#exit`
	7.	Verify the optical transmit power in the running configuration. Example: This example shows the running configuration for the optics controller: `Router#show run controller optics 0/2/0/16 Thu May 13 12:52:35.020 UTC controller Optics0/0/0/1 cd-min -4000 cd-max 4000 transmit-power -125 !`
	8.	Verify the configured optical transmit power on the optics controller. Example: This example shows how to verify the configured optical transmit power for the optics controller: Router#show controller optics 0/2/0/16 Fri May 28 02:52:06.182 UTC Controller State: Up Transport Admin State: In Service Laser State: Off LED State: Off FEC State: FEC ENABLED Optics Status Optics Type: QSFPDD 400G ZRP DWDM carrier Info: C BAND, MSA ITU Channel=80, Frequency=192.15THz, Wavelength=1560.200nm Alarm Status: ------------- Detected Alarms: None LOS/LOL/Fault Status: Alarm Statistics: ------------- HIGH-RX-PWR = 0 LOW-RX-PWR = 0 HIGH-TX-PWR = 0 LOW-TX-PWR = 0 HIGH-LBC = 0 HIGH-DGD = 0 OOR-CD = 0 OSNR = 0 WVL-OOL = 0 MEA = 0 IMPROPER-REM = 0 TX-POWER-PROV-MISMATCH = 0 Laser Bias Current = 0.0 mA Actual TX Power = -40.00 dBm RX Power = -40.00 dBm RX Signal Power = -40.00 dBm Frequency Offset = 0 MHz Laser Temperature = 0.00 Celsius Laser Age = 0 % DAC Rate = 1x1.25 Performance Monitoring: Enable THRESHOLD VALUES ---------------- Parameter High Alarm Low Alarm High Warning Low Warning ------------------------ ---------- --------- ------------ ----------- Rx Power Threshold(dBm) 13.0 -24.0 10.0 -22.0 Tx Power Threshold(dBm) 0.0 -16.0 -2.0 -14.0 LBC Threshold(mA) 0.00 0.00 0.00 0.00 Temp. Threshold(celsius) 80.00 -5.00 75.00 0.00 Voltage Threshold(volt) 3.46 3.13 3.43 3.16 LBC High Threshold = 98 % Configured Tx Power = -12.50 dBm Configured CD High Threshold = -5000 ps/nm Configured CD lower Threshold = -5000 ps/nm Configured OSNR lower Threshold = 9.00 dB Configured DGD Higher Threshold = 80.00 ps Baud Rate = 60.1385459900 GBd Modulation Type: 16QAM Chromatic Dispersion 0 ps/nm Configured CD-MIN -4000 ps/nm CD-MAX 4000 ps/nm Second Order Polarization Mode Dispersion = 0.00 ps^2 Optical Signal to Noise Ratio = 0.00 dB Polarization Dependent Loss = 0.00 dB Polarization Change Rate = 0.00 rad/s Differential Group Delay = 0.00 ps Temperature = 20.00 Celsius Voltage = 3.41 V Transceiver Vendor Details Form Factor : QSFP-DD Optics type : QSFPDD 400G ZRP Name : CISCO-ACACIA OUI Number : 7c.b2.5c Part Number : DP04QSDD-E30-19E Rev Number : 10 Serial Number : ACA244900GN PID : QDD-400G-ZRP-S VID : ES03 Firmware Version : 161.06 Date Code(yy/mm/dd) : 20/12/08

The optics controller is configured with the optical transmit power, and the controller output shows the configured Tx power value.

What to do next

Continue with related optical configuration tasks as required for your deployment.

Disable auto-squelching

Use this task to disable auto-squelch functionality on the module on the host side.

Table 2. Feature history table
Feature Name	Release Information	Description
Disable Auto-Squelching	Release 25.4.1	Introduced in this release on: Fixed Systems (8010 [ASIC: A100])(select variants only) This feature is supported on: 8011-32Y8L2H2FH 8011-12G12X4Y-A/D
Disable Auto-Squelching	Release 25.1.1	Introduced in this release on: Fixed Systems (8700 [ASIC: K100], 8010 [ASIC: A100])(select variants only) This feature is supported on: 8712-MOD-M 8011-4G24Y4H-I
Disable Auto-Squelching	Release 24.4.1	Introduced in this release on: Fixed Systems (8200 [ASIC: P100], 8700 [ASIC: P100])(select variants only); Modular Systems (8800 [LC ASIC: P100])(select variants only) *This feature is now supported on: 8212-48FH-M 8711-32FH-M 88-LC1-12TH24FH-E 88-LC1-36EH+A8:B12 88-LC1-52Y8H-EM
Disable Auto-Squelching	Release 7.11.1	This release introduces support to disable Auto squelching. This helps to detect weak signals that are hidden within the laser source noise. By disabling Auto squelch, you can reduce the processing overhead in systems that have stable laser sources and minimal noise, helping you optimize the performance of your system. When the Auto squelch function is enabled, the optical module generates a local fault signal on the host side if it detects a fault on the media side. By default, Auto squelch is enabled. The feature introduces these changes: CLI: The host auto-squelch disable keyword has been added. YANG data models: New XPaths for `Cisco-IOS-XR-controller-optics-cfg`. See GitHub and YANG Data Models Navigator.

When auto-squelch is enabled, the squelch function is activated on the module when no suitable media-side input signal from the remote end is available to be forwarded to the host-side output, such as when Rx LOS is asserted. Auto-squelching suppresses unwanted noise from laser sources in communication systems.

When auto-squelching is disabled and no valid signal is detected on the module from the remote end, the module generates a local fault towards the NPU. Disabling auto-squelching provides expanded signal detection and helps detect extremely weak signals that are embedded within laser source noise.

By eliminating the need to continuously monitor and suppress unwanted noise, system resources can be allocated more efficiently, leading to improved performance.

The host auto-squelch disable command disables auto-squelch functionality when there is an invalid input signal from the remote end. This feature provides the flexibility to customize the system behavior according to your requirements.

Before you begin

Identify the optics controller for the host on which you want to disable auto-squelching.

Procedure

	1.	Enter XR configuration mode. Example: `router#config`
	2.	Enter controller configuration mode. Example: `router(config)#controller 0/0/0/0`
	3.	Disable host auto-squelch. Example: `router(config-Optics)#host auto-squelch disable`
	4.	Commit the configuration. Example: `router(config-Optics)#commit`
	5.	Verify that host squelch is disabled. Example: This example shows how to verify the laser squelching disabled configuration: `router#show controllers optics 0/0/0/0 Host Squelch Status: disable`

Auto-squelching is disabled on the host side, and the optics controller output shows the host squelch status as disabled.

What to do next

Continue with related optical configuration or signal validation tasks as required for your deployment.

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Optical configuration

Configure frequency

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Configure chromatic dispersion

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Configure optical transmit power

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What to do next

Disable auto-squelching

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