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Prior to R10 release, the SON use case had control loop flows for PCI and ANR configuration changes based on O-RAN O1 interface (netconf interface from O-RAN SMO to the O-CU/O-DU). Control loop messages are forwarded from Policy to SDN-R. As shown in Figure 1, the netconf client in SDN-R communicates with netconf servers in the RAN-Sim RAN simulator which has abstracted functionality representing O-DU/O-CU in the RAN.
Figure 1: SON Use Case flow for O1-based control loop actions in ONAP Rel 3 to Rel 10
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As shown in Figure 2, there are operational policies in the Policy module which forward the control loop messages to SDN-R/O1 and SDN-R/A1-PMS.
For details on control loop policies and message formats, please see: R11 Control Loop Policy and Message Formats
There are new modules in the RAN-Sim RAN Simulator to terminate the A1 messages, along with a new ran-app modules representing an abstraction of an xApp hosted in the Near-RT RIC which interacts with the O-CU/O-DU in the RAN. For more details of the enhancements to RAN-Sim for A1 Support, please see: R11 Ran-Sim Enhancements .
Figure 2: SON Use Case flow for O1-based and A1-based control loop actions actions in ONAP Rel 11
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