What is DDS and what makes it unique

The OMG-DDS Data Distribution Service is an Object-Management-Group standard and technology to share any kind of data in ways that makes it interoperable, scalable, real-time, and fault-tolerant ways over arbitrary networks. DDS allows system designers to build stateful or stateless systems. The system's state is caught and represented in the data modeled by DDS.

DDS allows application developers to create digital twins of their systems' entities to share or query their states, share Commands or Replies, Events, data streams, videos, audios, structured documents and files, or simply share their messages on the network in real-time and in fault-tolerant ways.

With DDS, Data and their associated Quality of Services are the only contract that binds and integrates distributed applications together. From that perspective, DDS helps build decoupled and flexible distributed architectures where applications do not have to expose their location, their APIs, their internal behavior, nor need to be active and alive at the same time. With DDS, the decoupling is bidimensional, it happens both in Space and Time.\ This disruptive technology provides, secure, low-latency and ultra--high throughput data exchange rates.

Depending on the QoS (Quality of Services) in use, DDS behaves as an in-Memory database where, on behalf of every DDS-aware application, DDS replicates and maintains a local copy of the data based on the application's interest, which is expressed in the concept of data topic. DDS can manage the last data value or an arbitrary history of the updates. It can also store the data on persistent media to make it available for later use. When data is consistently propagated in the network, Applications can Query it, typically with a subset of the Structured Query Language (SQL), or use their own querying language.

In its minimalistic use, DDS behaves as a Message-oriented Middleware, where data throughput and latency performance can be considered more important than data consistency and coherency. In this case, applications can apply a filter to receive only the relevant data. These typical use-cases are not exclusive and can be combined within the same system or application.

As a standard-based technology with open specification, the OMG DDS technology fosters the development of secure interoperate open systems through the adoption of a common protocol (DDSI-RTPS) (DDS-Security). The technology also defines an application integration framework with intuitive and productive APIs available in the most popular and programming languages, ranging from C/C#/C++ to Python/Java/Scala and Javascript, etc... With such well-defined APIs, applications can be ported across compliant DDS implantations with minimal effort. Such standard APIs avoid the vendor locking situation.

In the next blog, we provide the ten most-distinguishing features that make DDS unique when comparing it to other Message-oriented Middleware or Distributed Databases Systems. We will discuss how DDS:

  1. simultaneously models system Things, their Relationships and Metadata,

  2. manages the best-effort deterministic data distribution on non-deterministic network transport layers,

  3. manages the last, or the history states, or both, and organizes them in the desired order,

  4. ensures Data Eventual Consistency and Coherency,

  5. provides Dynamic discovery with no single point of failure Defines Independent,

  6. manages best-effort deterministic data distribution on non-deterministic network transport layers Fault-tolerance and Horizontal scalability,

  7. builds complex information from basic data elements,

  8. manages integrity Rules on the Writing and Reading applications Ability to share data as well as the context in which it is published.

  9. provides a very rich Quality of Service Framework,

  10. provides Secure Data Distribution.

By Ramzi KAROUI, posted on 2022-11-08.