To support the daily work of network professionals, the following GPON network troubleshooting procedure has been compiled for study and reference. Start—Preliminary fault location—Check fiber status—Check ONU status—Check equipment operating status—Check equipment data configuration—Check upstream equipment status—End.
Common Issues
Issue 1 (Unable to access the Internet): Possible causes:
- User terminal failure
- Data configuration issues
- Upstream equipment issues
- Network attacks. Preliminary assessment of fault location and cause:
- User terminal or external line failure, e.g. PON port failure. Optical path issues.
- Data configuration issues, including: incorrect T-CONT template bound to the ONT. Examples: incorrect mapping between GEM Port and T-CONT. Incorrect mapping between GEM Port and service flow. Incorrect mapping between GEM Port and user-side VLAN. Incorrect VLAN channel configuration.
- All users on a board cannot access the Internet: board failure
- All users in a chassis cannot access the Internet: optical path issue / control board or uplink board failure / network attack. Issue 2 (ONU cannot register normally): Possible causes:
- Abnormal ONT optical port
- Poor fiber quality connected to the ONT
- Optical power on the ONU side is outside the normal range
- The logical nearest and farthest distances configured on the OLT port do not match the actual distances
- Auto-discovery is not enabled on the OLT port
- The SN of the ONT added on the OLT does not match the actual SN
- An ONT with the same SN already exists on the OLT. Preliminary assessment of fault location and cause:
- Check whether the ONT optical port is working normally.
- Use an optical power meter to check whether the ONT optical power is normal and whether the optical attenuation is appropriate.
- Check whether the ONT configuration is normal.
- Check whether the SN configured on the ONT matches the SN of the actual device.
- An ONT with the same SN may already be online on the OLT; please try replacing the ONU.
