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How to Solve the Failure of the Optical Module?

Dec. 14, 2020

When using an optical module, you will encounter a variety of failure problems more or less, such as whether the optical module model is selected correctly, whether the jumper used is correct, and other common problems. Customers have the ability to judge and have clear solutions. However, many customers do not know how to troubleshoot and solve certain problems that occur during use, such as abnormal transmission. 

Transmission troubleshooting and solutions

This type of fault problems mainly includes the port not being up, the port status is up but not receiving or sending packets, the port is frequently up or down, and CRC errors. The specific investigation methods and solutions are as follows:

Port is not up

Take the 10G SFP+/XFP optical module as an example. When the optical port of the optical module cannot be connected to other equipment, it can be checked from the following five aspects:

1.The first step is to check whether the speed and duplex mode of the ports at both ends match-execute the "show interface brief" command to check. If it does not match, configure the speed and duplex mode of the ports through the speed and duplex commands.

2.The second step is to check whether the speed and duplex mode of the device port and the optical module match-execute the "show interface brief" command to check. If it does not match, configure the speed and duplex mode of the port through the speed and duplex commands.

3.The third step is to check whether the ports at both ends are normal-test whether the ports at both ends can be up through loopback. Use 10G SFP+ direct-connect cables (suitable for short-distance connection, or use SFP+ optical modules and fibre jumpers) on the 10G SFP+ ports on the board for interconnection, and use XFP optical modules and optical fibres for testing on the 10G XFP ports To check whether the port can be up. If it can be up, it means that the opposite port is abnormal; if it cannot be up, it means that the local port is abnormal. You can check whether the fault is resolved by replacing the local and opposite ports.

 

10G SFP+

4.The fourth step is to check whether the optical module is normal-mainly to check whether the DDM, optical power, wavelength, distance and other parameters are normal. If it is not normal, replace the optical module that matches the optical interface.

DDM information-Use the "show interfaces transceiver detail" command to check whether the parameters are normal. If an alarm occurs, it means that the optical module is faulty or the optical module does not match the optical interface type.

Optical power-Use an optical power meter to test whether the port's receiving and emitting power is within the normal range and stable.

Wavelength/distance-Check whether the wavelength and distance of the optical modules at both ends are the same through the "show transceiver interface" command.

5.The fifth step is to check whether the optical fibre is a normal-for example, single-mode SFP+ optical module with single-mode optical fibre, and multi-mode SFP+ optical module with multi-mode optical fibre. If it does not match, replace it with the matching optical fibre immediately.

If the cause of the failure is still not found after the above inspections, it is recommended that you directly contact the supplier's technicians for technical assistance.