Hello, friend!
I understand that your question is about adding an OLT to U2000, correct?
Generally, if you need to manage a device through NMS, you need to configure the corresponding protocol on the device and NMS software. The common protocol is SNMP.
As the specific model of the OLT is not known, I'll take MA5800 as an example to describe how to commission the NMS. MA5800 provides the function of interconnecting with the NMS. The administrator can maintain and manage MA5800 through the NMS. The following link uses the iManager U2000 network management system (U2000 for short) as an example to describe how to commission the interconnection between the U2000 and the MA5800 in inband and outband modes. SNMPv3 has higher security than SNMPv1 and SNMPv2c. Therefore, it is recommended to use.
More information is available via the below links:
Thanks!