Check the optical module on the server

You can check a server's optical module using CLI commands on network devices or Linux tools like ethtool to view module type, vendor, link status, and DDM metrics.Checking on Cisco DevicesFor Cisco switches or servers with Cisco-compatible SFP/optical modules, use the CLI commands to inspect module details and health:List all installed modules: Switch# show inventory – displays Product ID (PID), Version ID (VID), and serial numbers .View detailed transceiver metrics: Switch# show interface GigabitEthernet1/0/1 transceiver detail – shows temperature, voltage, Tx/Rx optical power, and vendor information .Check port status and media type: Switch# show interfaces status – confirms link status, speed, duplex, and whether the port uses fiber or copper .These commands help detect installation issues, unsupported modules, or optical degradation early. Cisco optics often support Digital Diagnostic Monitoring (DDM), which provides real-time readings of temperature, voltage, and optical power .Checking on Linux ServersOn Linux servers with network cards using SFP or QSFP modules, you can use ethtool:Identify the network interface: ip link or ifconfigCheck transceiver details: ethtool -m (replace with eth0, p4p1, etc.) This displays:Module type (SFP, QSFP)Vendor name and part numberLaser wavelength and supported fiber typeMaximum supported distance and speedTx/Rx power, temperature, and bias current Check link status and speed: ethtool – shows link detected, speed, duplex, and auto-negotiation status .Monitoring and DiagnosticsDDM metrics: Monitor Tx/Rx optical power, temperature, and voltage to ensure the module operates within safe thresholds .Link verification: Confirm that the link is active (Link detected = yes) and that the negotiated speed matches expectations .Vendor and compatibility: Verify the module vendor, part number, and wavelength to ensure compatibility with your server or switch .Best PracticesPeriodically check optical module health to prevent unexpected link drops and extend hardware lifespan .Use vendor-specific tools or CLI commands for more detailed diagnostics if available.Document module serial numbers and installation locations for inventory management and troubleshooting.By following these steps, you can effectively verify the operational status, health, and compatibility of your server's optical modules, ensuring reliable network connectivity.