Connectivity Framework Annex A: Assessment Template: DDS
A. 6.3 Usage Viewpoint
A. 6.3.1 Architecture( Section 6.3.1)
Summarize the main concepts, and high-level architecture, and terminology. Describe the end-to-end information exchange path.
DDS provides a“ middleware” software layer that abstracts an application from the details of the operating system, network transport, and low-level data formats. An application links to a DDS middleware library to participate in an data exchange. The same concepts and APIs are provided in different programming languages allowing applications to exchange data across of operating systems, languages and processor architectures. Lowlevel details like data wire format, discovery, connections, reliability, timing and QoS management are managed by the middleware layer. It integrates the components of a system together, providing low-latency data connectivity, extreme reliability and a scalable architecture that business and mission-critical Internet of Things( IoT) applications need.
Participant X Participant Y
Information |
Distributed Data Interoperability and Management |
Information( Data in Context) |
Distributed Data Interoperability and Management |
|
Framework |
Data( State, Events, Streams) |
Framework |
Connectivity |
|
|
|
|
Transport |
Messages |
Transport |
Networking |
Network |
Packets |
Network |
|
Link |
Frames |
Link |
|
Physical |
Bits |
Physical |
A. 6.3.2 Technology Options
( Section 6.3.2)
DDS organizes the data exchange between applications as a shared data space. A DDS- DomainParticipant represents an application’ s participation in a data space. Within that data space, a collection of data objects with the same structure( data type) and behavior( QoS) is represented by a named DDS-Topic. A DDS-DataWriter is used to publish updates to one or more data objects on a DDS-Topic. A DDS-DataReader is used to subscribe to updates to one or more data objects on a DDS-Topic.
Updates to data objects on a DDS-Topic originate at a DDS-DataWriter, and are sent directly to all the DDS-DataReaders associated with that DDS-Topic. The data paths are direct and peer-to-peer, with no server or broker in the middle. An application can participate in one or more data spaces. A content-filter can filter can be used to specify the subset of updates of interest to a DataReader. Only the relevant updates are delivered, as defined by the content-filter and the QoS configuration specific to the DDS-DataWriter and DDS-DataReader pair. List the choices to be made for using the connectivity technology in a system.
Selection of the DDS implementation. Note that the applications participating in a data exchange may use different implementations.
IIC: PUB: G5: V1.0: PB: 20170228- 63-