Connectivity Framework
7 : Connectivity Standards
Similar to the way a database controls access to stored data , a databus controls data access and updates by many simultaneous components . At its core , DDS is built around a data-centric publish-subscribe data exchange pattern . However , the standard also defines a request-reply data exchange pattern , and vendors offer queuing . The key abstraction is that applications interact with the databus itself , not directly with other applications participating in that interaction . DDS offers precise data-centric quality-of-service ( QoS ) control , reliable multicast , configurable delivery , multiple levels of data durability , history , component and transport redundancy , automatic discovery , connectivity management , and transport agnostic fine-grained data-centric security . In addition , one-to-many and many-to-one communications is a key strength . DDS offers powerful ways to filter and select exactly which data goes where , and “ where ” can be thousands of simultaneous components . To support small , edge devices , there are lightweight versions of DDS that run in constrained environments . The DDS databus ensures ultra-reliable operation and simplifies application code . It does not require servers , greatly easing configuration and operations while eliminating failure and choke points .
A DDS-based system has no hard-coded interactions between components . The DDS databus automatically discovers and connects publishing and subscribing components . No configuration changes are required to add new components ( e . g . a smart machine ) to a system . Components can be developed or sourced from independent parties . DDS overcomes problems associated with point-to-point system integration , such as lack of scalability , interoperability and the ability to evolve the architecture . It enables plug-and-play simplicity , scalability and exceptionally high real-time performance .
DDS is commonly used for system integration and for building autonomous systems , because of the flexibility , reliability and speed necessary to build complex or real-time applications . DDS is a proven technology for reliable , high performance , large-scale IIoT software systems across many vertical industries . IIoT applications using DDS include wind farms , hospital integration , medical imaging , autonomous planes and cars , rail , asset tracking , automotive testing , smart cities , communications , data center switches , video sharing , consumer electronics , oil & gas drilling , ships , avionics , broadcast television , air traffic control , SCADA , robotics and defense .
DDS Gateways exist for many other connectivity technologies , including DNP3 , C37.118 , Modbus , HLA , JMS and so on . The DDS-Web v1.0 specification 1 defines a standardized gateway for Web Services . A standard for a gateway between OPC-UA and DDS is underway at the OMG . The OPC Foundation is developing an OPC-UA-DDS pubsub profile 2 with the goal of adding DDS as an additional publish-subscribe communication option to OPC-UA . Work is underway at oneM2M , investigating an interworking gateway between oneM2M and DDS , a DDS protocol binding for oneM2M , and DDS based direct exchange of data between oneM2M entities 3 .
1
See [ OMG-DDSWEB ]
2
See [ OPC-DDS ]
3
See [ ONEM2M-27 ]
IIC : PUB : G5 : V1.0 : PB : 20170228 - 48 -