Data Delivery Object (DDO)¶

A DDO (Data Delivery Object) is the fundamental unit of data exchange in the DaaS-IoT overlay.
Every message, event, telemetry packet, configuration update, or synchronization signal is encapsulated inside a DDO.

DDOs provide a unified abstraction over heterogeneous transports (INET4, Bluetooth, etc.), ensuring consistent behavior across platforms.

1. Purpose of a DDO¶

A DDO serves as a self-describing container that includes:

message metadata
routing and addressing information
semantic classification (typeset)
payload data
timing information

This abstraction allows DaaS-IoT to remain independent of the underlying transport layer while preserving deterministic message handling.

2. Structure of a DDO¶

A typical DDO includes the following fields:

DIN¶

The unique 32-bit identifier of the sender or receiver node.

Typeset¶

A 16-bit message classifier describing the semantic meaning of the payload.

Timestamp¶

Time-synchronization metadata used for ordering, delay estimation and diagnostics.

Payload¶

The raw binary content interpreted according to the typeset schema.

Size¶

Total payload length (in bytes).

3. DDO Lifecycle¶

1. Creation¶

The sender node constructs a DDO, sets its typeset, attaches the payload and prepares it for transmission.

2. Serialization¶

The DDO is encoded into a transport-ready buffer by the SDK.

3. Transmission¶

Drivers (INET4, Bluetooth, etc.) deliver the DDO to the destination DIN.

4. Reception¶

The receiving node reconstructs the DDO and extracts metadata and payload.

5. Handling¶

Based on the typeset, the DDO is dispatched to the correct handler, decoder or subsystem.

4. Role of DDOs in the Overlay¶

DDOs provide:

consistency across heterogeneous transports
predictable message boundaries
timestamp-based ordering
integration with routing metrics
support for system messages (Frisbees, dATS packets, topology updates)

The DaaS-IoT Python binding (pydaasiot) exposes high-level APIs to construct, manipulate and inspect DDOs directly.

Summary¶

DDOs form the backbone of communication in the DaaS-IoT overlay, delivering a clean, transport-independent mechanism for reliable, structured message exchange across nodes.