From a dark box
to a live cell.
The M-plane is how a metal box on a mast becomes a working cell. Here we read a YANG tree over NETCONF, decide hierarchical vs hybrid, watch the O-RU call home by itself (DHCP → call-home → capabilities → PNF registration), wire the planes with real modules (o-ran-interfaces, o-ran-processing-element), push software (download/install/activate), and light a carrier in o-ran-uplane-conf. Verbatim from O-RAN WG4 MP.0 v21.01 + its 95 YANG modules.
The M-plane — NETCONF, YANG, and O-RU bring-up
The player screen is a live animation stage — a YANG tree unfolds, the O-RU climbs its call-home ladder rung by rung, the eAxC flows bind to VLANs, software slots swap, and a carrier keys up until the arrays go active, exactly as the narration reaches each idea. Karaoke subtitles EN + Persian, fullscreen.
The modules that configure an O-RU
These are real module names from the O-RAN MP-YANGs v21.01 package (95 modules). Click one to see what it configures on the radio.
How a new O-RU joins — it calls home
The O-RU is not discovered — it phones home by itself. These five rungs run before any real config, and they are your integration checklist.
| # | Step | What happens | Clause |
|---|---|---|---|
| 1 | DHCP | O-RU powers up, requests an IP + learns its NETCONF controller | §7.4 |
| 2 | NETCONF call home | the O-RU initiates the connection to the controller | §6.3 |
| 3 | Secure session | TLS or SSH channel established | §6.4 |
| 4 | Capability discovery | O-RU declares its supported YANG modules & features | §6.6 |
| 5 | PNF registration | O-RU registers as a physical network function | §6.9 |
If an O-RU never appears in the controller, walk these rungs in order: DHCP lease? → called home? → secure session up? → capabilities exchanged? → registered? Nine times out of ten a radio that will not integrate failed on one of the first rungs — and the fix is never "swap the radio."
The modules you actually touch
| Module | Configures | Stage |
|---|---|---|
| o-ran-mplane-int | M-plane connectivity / call-home endpoints | connect |
| o-ran-dhcp | address acquisition | connect |
| o-ran-module-cap | declared capabilities | discover |
| o-ran-interfaces | VLAN + IP transport | wire planes |
| o-ran-processing-element | eAxC flow → VLAN/MAC/IP mapping | wire planes |
| o-ran-uplane-conf | carriers, endpoints, arrays — carrier bring-up | activate |
| o-ran-beamforming | beam tables / weights | activate |
| o-ran-software-management | download / install / activate | software |
| o-ran-fm | fault / alarm notifications | operate |
| o-ran-sync | lock-state / PTP / GNSS (M5 tie-in) | operate |
o-ran-processing-element is where the eAxC identifiers from Chapter 2 finally get their VLAN and MAC bindings — it is the join between the M-plane you configure and the C/U-plane flows that carry the traffic. Configure it wrong and the fronthaul is "up" but silent.
Who is the NETCONF client?
| Model | Who manages the O-RU | Trade-off |
|---|---|---|
| Hierarchical | only the O-DU | one client, simplest — SMO reaches the O-RU only via the O-DU |
| Hybrid | both the O-DU and the SMO | SMO can manage directly — but two clients can conflict |
This choice colours every step that follows. In hybrid, if the O-DU and the SMO both push config to the same O-RU without coordination, their NETCONF sessions fight over the radio. Decide the management architecture before you rack the first O-RU — it is not a setting you flip later.
🛠 Engineer detail block — what you'll actually meet in the field
- The O-RU calls YOU. Stop looking for a "discover radio" button — NETCONF call home means the O-RU initiates. If it never shows up, the fault is DHCP, the call-home address, or the secure session, in that order.
- o-ran-processing-element is where eAxC lives. The single most common "fronthaul up but silent" bug is a VLAN/eAxC binding mismatch here versus what the O-DU expects. Chapter 2's bit-plan meets Chapter 6's YANG.
- Two software slots are not optional. Download + install to the inactive slot, activate, and keep the old slot bootable. A remote O-RU that bricks on a bad load is a truck roll — the fallback slot is why you avoid it.
- Hybrid M-plane needs a referee. When both O-DU and SMO manage one O-RU, you must define who owns which config, or their edit-configs will clobber each other. Decide it in design, not at 3 a.m.
- o-ran-sync closes the loop with M5. The sync objects you read here are the same lock-state / PTP / GNSS you diagnosed in Chapter 5 — the M-plane is how you actually observe the S-plane.