How to check optical modules in Cisco

You can view Cisco optical module (SFP) information using either the web-based utility or CLI commands to check module type, serial number, vendor, and diagnostic metrics like Tx/Rx power, temperature, and voltage.

Using the Web-

Based Utility

Log in to your Cisco switch's web interface. Navigate to Status and Statistics > Diagnostics > Optical Module Status (example: SG350X-48MP switch). Select the switch and port from the drop-down list and click Go.

The page displays: Port: Port number of the SFPDescription: Optical transceiver descriptionSerial Number & PID/VID: Identification of the moduleTemperature, Voltage, Current: Operating metricsOutput/Input Power: Transmit and receive optical powerTransmitter Fault & Loss of Signal: Status indicatorsData Ready: Operational status This method is useful for monitoring module health and troubleshooting fiber connections.

Using CL

I CommandsSSH or console into the switch. Run the following commands depending on your Cisco platform and IOS version:show interface: Displays port link status, negotiation speed, and transceiver type.show interface status: Lists all ports with their operational status.show inventory: Lists installed hardware including SFP modules with PID, VID, and serial number.show interfaces transceiver detail or show interface transceiver detail: Reads DOM/DDM metrics such as Tx/Rx power, temperature, voltage, and bias current.show idprom interface or show idprom transceiver extended: Retrieves EEPROM/vendor information.show logging: Checks for unsupported transceiver messages or errors.

Optional tests:test interface transceiver (if supported) to verify module functionality. Monitor error counters via show interface to detect CRC or input errors indicating cable or connector issues.

Key Notes

Ensure the SFP module is supported by your Cisco switch; unsupported modules may show errors.

CL

I commands provide more detailed diagnostic data than the web interface, including real-time optical power and temperature. Both methods help in inventory management, troubleshooting, and verifying module compatibility. By following these steps, you can effectively monitor and manage Cisco optical modules, ensuring reliable fiber connectivity and early detection of potential issues.