OpenDDS vs. RTI Connext DDS: Choosing the Right Data Distribution Service Solution

The OMG Data Distribution Service (DDS) standard is an open standard, meaning it is publicly available and provides a normative reference that ensures consistency, portability and interoperability across implementations. Unlike open‑source software, which is distributed with its source code, an open standard can be realized in many ways, including through open‑source implementations such as OpenDDS, managed by OCI (Object Computing Inc.). Commercial distributions, most notably RTI’s Connext® DDS, also adhere to the same standard but offer additional features, support and proven reliability.

When choosing between an open‑source DDS solution and a commercial one, consider the specific capabilities you require, the level of support you need, and the criticality of your application.

Open‑Source DDS Core Features

Open‑source DDS often delivers a full implementation of the DDS API, making it a solid foundation for most projects. However, commercial DDS like RTI Connext provides a broader feature set that can be decisive for mission‑critical or highly specialized applications.

Standard OMG DDS Capabilities Offered by RTI Connext (Not Commonly in Open‑Source)

• Multi‑language support – C++, C++03, C++11, Java, Ada, C# and .NET (OpenDDS only offers traditional C++).
• Presentation QoS – control sample arrival order at the subscriber.
• Writer‑side content filtering – reduces bandwidth and CPU usage on receivers.
• Extensible type definitions – flexible data type evolution without sacrificing portability or expressiveness.
• Request/reply paradigm – a messaging pattern defined by the OMG standard.
• XML QoS configuration – specify QoS settings via XML files.
• Coherent data across topics – achieved with coherent sets and presentation scopes.

Enhanced (Non‑Standard) Features in RTI Connext

• Delivery guarantees – application‑level acknowledgments, virtual GUIDs for redundant routing, durable subscriptions and writers, and collaborative datawriters.
• Packet batching – combine small packets for higher throughput.
• Historical data queries – retrieve past data from topics.
• IP mobility – dynamic addition, removal, and modification of IP connections.

Application Components and Services Beyond the Core DDS

Commercial DDS often bundles services that simplify integration with external systems and accelerate development:

• Routing Service – forwards and transforms data across networks.
• Record & Replay Service – captures high‑speed data for playback to live or simulated systems.
• Database Integration Service – persist DDS data in relational databases and monitor changes via DDS.
• Web Integration Service – expose DDS data over HTTP for browser‑based applications.
• Persistence Service – maintain data availability for late‑joining applications.
• DDS Connectors – scripting interfaces for Python, JavaScript and Lua.
• System Designer – graphical configuration of DDS systems.
• Prototyper – rapid prototyping, testing and exercising of DDS deployments.
• Cloud Discovery Service – deploy DDS in cloud environments.

Tools for DDS Implementation

Robust tooling is essential for debugging complex distributed systems. RTI Connext offers a comprehensive suite:

• Admin Console – visualise participants, topics, writers, readers, QoS settings and data types; auto‑detect connection issues.
• Monitor – detailed insights into DDS entities, traffic and internal state.
• rtiddsspy – command‑line utility to inspect published and subscribed data.
• Excel Add‑in – read/write DDS data directly from Microsoft Excel.
• Heap Analysis Tool – capture DDS heap snapshots and identify memory leaks.

DDS Security

Open‑source DDS typically lacks built‑in support for the DDS Security standard, TLS or DTLS transports. RTI Connext DDS has implemented the DDS Security standard since its Secure beta in 2015 and offers a Secure WAN transport that includes TLS/DTLS. For more details, consult the RTI Connext DDS Secure documentation.

Certification

Certification can be critical for regulated industries. RTI Connext DDS Cert, a certified subset of the DDS API, has achieved DO178C Level A certification. See the Connext DDS Cert overview for full specifications.

Robustness

Field performance is the ultimate benchmark. Connext DDS has been deployed in over 1,000 projects and runs on more than 1 million devices worldwide. Notable use cases include:

• Grand Coulee Dam – 24/7 operation, 300,000 data points.
• NASA KSC Launch Control – 300,000 points at 400,000 messages per second.
• Raytheon Zumwalt destroyer – 1,500 DDS applications, 10 million publishable pairs.
• Shanghai PVG Airport Ground Control – standardized across Southeast China Regional Airports since 2015.

RTI invests heavily in testing, with extensive automated suites, rigorous training, and the industry’s largest IIoT Testing Lab, featuring 240‑core scale tests, 32 Xeon CPUs, 128‑board micro arrays, and nearly 100 different computer types.

Platform Support

Ensure your target architecture, OS and compiler are supported. Connext DDS covers the widest range of platforms in the industry. If a platform is unsupported, open‑source DDS can be rebuilt from source with provided instructions. However, rebuilding libraries requires careful validation to match the rigor of commercial releases.

Cost

Open‑source DDS may appear cheaper initially, but hidden costs arise: missing features, additional development effort, and reliance on community or third‑party support. Commercial DDS offers a clear cost structure and dedicated support, which can reduce time‑to‑market and long‑term maintenance expenses.

Time to Market

Speed matters. Commercial DDS provides a more complete feature set, robust tooling, and proven reliability, often reducing development cycles. With over 50 engineers dedicated to Connext DDS development and an additional support team, the risk of delays is minimized.

DDS Support

Support quality is critical for mission‑critical applications. RTI offers 24/7 support through US and Europe centers, with engineers who specialize in distributed real‑time and embedded systems. Their escalation policies, direct access to development resources, and rich online documentation—including user group articles, instructional videos, example code and training—ensure rapid problem resolution.

Getting Started with RTI Connext DDS

Define your requirements clearly before selecting an implementation. Consider the following questions:

• Is your preferred programming language supported?
• Do you need integration with scripting languages?
• Will you require cloud or relational‑database connectivity?
• Is future security or certification a concern?
• Do you need a release that has undergone rigorous testing and field deployment?

If your product demands rapid delivery, rock‑solid performance, comprehensive support and a future‑proof feature set, RTI Connext DDS is the logical choice.