The following diagram shows the relation between modules and the flow of information between them.

Arguments included in ofp_state_s::udal (UDAL) are called UDA (User-Defined Argument),
but arguments inputted in the command-line are called UIA (User-Inputed Argument).
Options are either Double-UIA (DUIA) or Single-UIA (SUIA).
DUIA options consist of two UIA, first one is the UDA identifier and the second one is the UDA value.
/option value
SUIA options consist of one UIA, including the UDA identifier and the UDA value.
/optionvalue
The OFP state contains 3 major argument lists.