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 -