Troubleshooting Cisco C9300-NM-8X: Why Your Module's LEDs Aren't Lighting Up During POST
Selene Gong
When deploying or troubleshooting Cisco Catalyst 9300 switches, many IT administrators wonder: "Should the Cisco C9300-NM-8X module’s LEDs light up during POST?"
Yes, during POST (Power-On Self-Test), the C9300-NM-8X’s LEDs should illuminate briefly if the module is recognized and functioning correctly. This indicates the switch has detected the module, allowing the ports to initialize and become operational. If your module's LEDs remain unlit, it often signals an installation, compatibility, or hardware issue requiring prompt attention.
What LED Behavior Should You Expect from the C9300-NM-8X During POST?
The Cisco C9300-NM-8X adds eight 10GE SFP+ uplink ports to your Catalyst 9300 switch, supporting 1G and 10G SFP/SFP+ transceivers.
Expected LED indicators during POST:
Green (solid or blinking): Normal detection and initialization
Blinking amber: Link fault or incompatible cabling
Off: Module is not detected or no link is established
Monitoring these indicators during POST helps confirm hardware readiness and simplifies troubleshooting if ports remain inactive.
Why Are the LEDs on My C9300-NM-8X Not Lighting Up?
If your C9300-NM-8X LEDs remain off, consider these possible reasons:
Is the Module Fully Seated?
Ensure the module is inserted firmly with the jackscrew tightened to secure electrical contact. Modules may feel seated but fail to connect fully without tightening. Always disconnect cables during insertion or removal.
Are Supported Transceivers Being Used?
Use Cisco-approved SFP/SFP+ modules (for example, SFP-10G-SR). Unsupported or faulty transceivers can prevent the ports from coming up. Check detection with:
show inventory
show hw-module subslot 0/0 transceiver 0 idprom
Is Your IOS XE Version Compatible?
Firmware incompatibility can prevent module initialization. Check your version:
show version
Modules may operate under IOS XE 16.x but fail under 17.x without updates. Refer to Cisco release notes to confirm compatibility.
Are Port Configuration or Speed Settings Causing Issues?
The module’s ports appear as TenGigabitEthernet1/1/1 through 1/1/8, even when using 1G SFP modules. Speed or duplex mismatches can prevent link establishment. Verify and adjust configurations:
show interfaces status
To manually adjust:
interface TenGigabitEthernet 1/1/1
speed 1000
duplex full
no shutdown
Are There Cabling or Physical Layer Issues?
Faulty cables or noncompliant connections can prevent links from establishing. Even if the connected device shows activity, the Catalyst 9300 may not detect a stable link. Look for blinking amber LEDs indicating faults.
How Can You Troubleshoot C9300-NM-8X Ports Not Lighting Up?
Use these steps to identify and resolve issues:
Reseat the module securely, tightening the jackscrew.
Check and reinsert transceivers, ensuring they are clean and supported.
Verify and update the switch’s IOS XE version if needed.
Review and adjust interface configurations for correct speed and duplex.
Replace cables with known-good, compliant alternatives.
Monitor system logs for detection events:
show log | include MODULE
Testing the module in another working Catalyst 9300 switch can help confirm whether the issue lies with the module or the host switch.
Frequently Asked Questions
Q1.Can I use 1G SFP modules in the C9300-NM-8X? Yes, but the interfaces will appear as TenGigabitEthernet, and configuration may be needed for 1G operation.
Q2.What does “line protocol is down (notconnect)” mean on NM ports? This indicates a physical connectivity issue, such as cable faults, unsupported transceivers, or no signal from the connected device.
Q3.Is the C9300-NM-8X hot-swappable? Yes, but always remove cables and use ESD protection when handling the module.
Q4.Do I need to configure anything to use NM ports? Ports are typically ready for use but may require manual speed and duplex settings depending on connected devices.
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