BBSim Internals

Other Resources:

• Development dependencies

BBSim heavily leverages state machines to control the device lifecycle and channels to propagate and react to state changes.

The most common pattern throughout the code is that any operations, for example a gRPC call to the ActivateOnu endpoint will result in:

1. A state change in the ONU device, that will

2. Send a message on the ONU Channel, that will

3. Trigger some operation (for example send Indications to the OLT)

OLT State Machine

Here is a list of possible states for an OLT:

OLT States

	Initialized	Enabled	Disabled	Deleted
Data model is created for OLT, NNIs, PONs and ONUs	Starts the listener on the NNI interface and the DHCP server, Starts the OLT gRPC server, Moves the ONUs to initialized state	Sends OLT, NNIs and PONs UP indications Transition the ONUs into discovered state	Transition the ONUs into disabled state Sends OLT, NNIs and PONs UP indications	Stops the OLT gRPC Server

Below is a diagram of the state machine allowed transitions:

ONU State Machine

Here is a list of possible state transitions for an ONU in BBSim:

ONU States

Transition	Starting States	End State	Notes
		created
initialize	created, disabled, pon_disabled	initialized
discover	initialized	discovered
enable	discovered, disabled, pon_disabled	enabled
disable	enabled	disabled	This state signifies that the ONU has been disabled
pon_disabled	enabled	pon_disabled	This state signifies that the parent PON Port has been disabled, the ONU state hasn’t been affected.

Below is a diagram of the state machine:

• In blue PON related states

• In purple operator driven states

Service State Machine