Question 1
A network engineer is troubleshooting a new GPON deployment where an ONT fails to register with the MA5800 OLT. The ONT is in a constant cycle of attempting to range. The optical power at the ONT is measured at -22 dBm, which is well within the receiver's sensitivity range. The OLT logs show 'Ranging failure' for the ONT's serial number. Which of the following is the most probable cause for this specific issue?
Answer and explanation
Correct answer: B
While sufficient optical power is necessary, it is not the only requirement for successful registration. The GPON standard includes a management protocol called OMCI (ONT Management and Control Interface) for the OLT to manage the ONT. If the ONT is from a non-certified third-party vendor, its OMCI implementation may be incompatible with the Huawei OLT, leading to a failure during the ranging and provisioning process, even with perfect optical levels. A -22 dBm signal is a healthy level, not too high. A rogue ONT would typically cause issues for other ONTs on the same PON port. Incorrect VLAN configuration affects service provisioning after registration, not the ranging process itself.