GPON ONU O1-O7 state transition

1. Initial-state(O1)

When onu is powered on, it will be in this state, that is, LOS/LOF state.

2. Standby-state(O2)

When onu receives a downstream traffic, it enters the O2 state.

When onu receives a data packet of the Upstream_Overhead message type, it will configure some corresponding options, including delimiter value, power level mode, and pre-assigned equalization delay

3. Serial-Number-state(O3)

After entering O3, olt will send a Serial_Number request to onu, and then onu will reply to olt with its SN+Passwd. After olt passes the authentication, it will send an onuID to onu through the Assign_ONU-ID message. When onu receives the ONUID , it enters the O4 state

4. Ranging-state(O4)

Ranging state, logical ranging stage, after receiving the reply sent by olt, it enters O5

5. Operation-state (O5)

After entering this state, onu can directly send uplink data and ploam messages

6. POPUP-state(O6)

When the optical signal is detected to be lost, it enters this state and then transfers to the O1 state.

7. Emergency-Stop-state(O7)

When onu receives the Disable_Serial_Number message, it enters this state and then transfers to the O2 state.