First, to understand the function of the fronthaul M-Plane, let’s remember the Fronthaul Planes, Please read this and continue.
What is the M-Plane?
Management Plane: refers to non-real-time management operations between the O-DU and the O-RU like:
- Performance Management (PM).
- Configuration Management (CM).
- Fault Management (FM).
- File Management.
What are the M-Plane Archtecture?
The M-Plane supports two architectural models for O-RU Management:
- Hierarchical management model
- The O-RU is managed entirely by one or more O-DU(s) using a NETCONF-based M-Plane interface. When the O-RU is managed by multiple O-DUs, it is typically for enabling O-DU and/or transport connectivity redundancy capabilities.
- Hybrid Management model
- The hybrid architecture enables one or more direct logical interfaces between management systems and O-RU in addition to a logical interface between O-DU and the O-RU ( Which is called here Open Fronthaul M-Plane).
- It should be noted that the NETCONF clients connecting to the O-RU may be of different classes (e.g. O-DU and NMS). For example, functions like O-RU software management, performance management, configuration management, and fault management can be managed directly by the management system(s).
- The O-RU has end-to-end IP layer connectivity with the NMS. From a physical network point of view, this connectivity could be via the O-DU, where the O-DU is acting as an IP/Ethernet packet forwarder, and forwards the packets between O-RU and the NMS.
- Direct logical communication between an O-RU and NMS can be enabled via O-RUs being assigned routable IPs or local private IPs resolved by a NAT function in the network (or implemented at the O-DU).
- Configuration of “non-carrier” aspects of an O-RU together with functions like O-RU software management, file management, trace, and troubleshooting are managed directly by the management system (e.g., SMO).
- For carrier-related parts, management is performed by the OAM function of the O- DU, based on SMO-provided configuration information via the O1.
- There is no explicit signaling to indicate that an O-RU is operating in a hierarchical or hybrid configuration. All NETCONF servers supporting this M-Plane specification shall support multiple NETCONF sessions, and hence all complaint O-RUs shall be able to support both hierarchical and hybrid deployment.
- NETCONF server exists in O-RU.
- NETCONF Client exists in O-RU Controller which can be O-DU or NMS.
- NETCONF also natively supports a hybrid architecture that enables multiple clients to subscribe and receive information originating at the NETCONF server in the O-RU.