Check the router s optical module

You can check a router's optical module by using CLI commands to view port status, transceiver details, and real-time optical parameters such as Tx/Rx power, temperature, and voltage.

Step 1: Access the Router or Switch

Log in to your router or switch via SSH, console, or Telnet using administrative credentials. Ensure you are in privileged EXEC mode or equivalent to run diagnostic commands .

Step 2: Verify Interface Status

Check whether the port connected to the optical module is active:

• Cisco: show interface status — displays link status (up/down), speed, and port type .
• Huawei: display interface — shows interface operational status and basic link information . If the port shows “notconnect”, the issue may be with the fiber cable, remote device, or the SFP module itself .

Step 3: Identify the Installed Optical Module

Determine which transceiver is installed:

• Cisco: show inventory — lists installed SFPs with part number, vendor, and serial number .
• Huawei: display transceiver interface — shows module type and certification status .

Step 4: Check Optical Parameters

Read real-time optical monitoring data (DOM/DDM) to assess module health:

• Cisco: show interfaces transceiver detail — provides Tx/Rx power, temperature, voltage, and bias current .
• Huawei: display transceiver diagnosis interface — shows digital diagnostic monitoring information . Typical parameters to monitor:
• Transmit (Tx) and Receive (Rx) power — ensures signal strength is within normal range.
• Temperature and voltage — detects overheating or power issues.
• Bias current — indicates laser diode health.

Step 5: Troubleshoot Issues

• If the module is not detected, it may be incompatible or faulty.
• Low Rx power may indicate a damaged or too-long fiber cable.
• Abnormal temperature or voltage suggests overheating or hardware failure .

Step 6: Optional Advanced Checks

• EEPROM/vendor info: show idprom interface (Cisco) — confirms module manufacturer and serial number .
• Verbose diagnostics: Some platforms allow verbose flags to get detailed operational metrics . Regularly performing these checks helps maintain stable fiber-optic connections and quickly identifies failing or incompatible optical modules.