Huawei switch has abnormal light reception

Poor light reception on a Huawei switch is usually caused by incompatible optical modules, fiber issues, or incorrect transceiver power levels, and can be resolved through systematic checks and adjustments.

Common Causes

Optical Module and Fiber Incompatibility Ensure that the optical module type matches the fiber type. Single-mode modules must be used with single-mode fiber, and multimode modules with multimode fiber. Mixing these can prevent proper light reception.

Transceiver Power Issues

Low R

X Power: If the received optical power is below the module's threshold, the port may go down or experience packet loss. This can occur if the fiber distance exceeds the module's limit or if the module/fiber is damaged.

High R

X Power: Excessive received power can damage the transceiver. Use optical attenuators if necessary.

T

X Power Problems: Low or high sending power can also affect reception at the remote end.

Physical Connection Problems

Loose or improperly seated optical modules can cause poor reception. Re-plugging the module may restore the link. Fiber jumpers connected to the wrong ports or damaged fibers can prevent signal transmission.

Swapping fiber ends or testing with a loopback can help identify the faulty segment.

Interface Configuration Issues

Check if the port is administratively down using display interface and run undo shutdown if necessary. Ensure the interface rate, duplex mode, and auto-negotiation settings are consistent on both ends.

Troubleshooting Steps

Verify Module and Fiber Compatibility Confirm that the optical module and fiber type match and that the module's rate does not exceed the interface capability. Check Optical Power Levels Use the command display transceiver interface verbose to view RX and TX power. Compare against the module's normal range.

Inspect Physical Connections Re-seat the optical module, check fiber jumpers for damage, and perform a loopback test to isolate the problem. Review Interface Status Run display interface brief to check if the port is up. If the port is down, verify configuration and run undo shutdown if needed.

Replace Faulty Components If the optical module or fiber jumper is defective, replace it and observe the port indicator light. By systematically checking compatibility, power levels, physical connections, and interface settings, most poor light reception issues on Huawei switches can be resolved efficiently.