Connectivity at the Core: The Status of DDS in AUTOSAR
Written by Emilio Guijarro
September 20, 2022
Since 2016, RTI and the AUTOSAR consortium have been in direct contact through AUTOSAR’s Intra-Vehicle Communications Working Group (WG-IVC). Many AUTOSAR automotive experts have since recognized RTI’s expertise and experience in the standardization, development and support of DDS-related technologies. As a result, AUTOSAR has been hosting and supporting the development of DDS for more than five years within its Classic and Adaptive software platforms.
Before jumping into the specification status of each of these platforms, let's define these acronyms:
- AUTOSAR (AUTomotive Open System ARchitecture) is a worldwide development partnership of vehicle manufacturers, suppliers, service providers and companies from the automotive electronics, semiconductor and software industry.
- DDS is a middleware protocol and API standard for data-centric connectivity from the Object Management Group® (OMG® ). It integrates the components of a system together, providing low-latency data connectivity, extreme reliability, and a scalable architecture that business, safe and mission-critical applications need.
As you may infer from the above definitions, AUTOSAR and DDS can complement each other extremely well, as automotive systems keep growing in complexity, and thus require more flexible, interoperable and full-featured communication frameworks. This is the advantage of using DDS in AUTOSAR to help deliver connectivity at the core.
Status of DDS in the AUTOSAR Adaptive Platform
Since DDS was introduced in AUTOSAR through the Adaptive Platform’s Communication Management Functional Cluster (commonly referred to as “ara::com”), the Adaptive Platform has long reaped the benefits of comprehensive standard materials for DDS-oriented communications management.
The centerpiece of this approach is the “DDS Network Binding” section of “Specification of Communication Management”, which in Release 22-11 of AUTOSAR will reach its fifth edition. In this section, the language-independent, service-oriented semantics of ara::com are mapped to the DDS standard type system and APIs. This section details:
- How Service Interfaces are expressed in the DDS-IDL language
- How Service Instance providers and consumers exchange data in run-time
- How Service Instances are advertised, discovered, and bound to
This functionality has been present and improving since AUTOSAR Release 18-03, but since then it has received many eagerly anticipated additions and improvements. These upgrades include:
- Analysis on DDS safety measures with regards to ISO-26262 requirements for safe communication
- Topic-based Service Instance advertisement/discovery (validated towards R22-11)
- DDS-SECURITY™ integration with AUTOSAR’s Identity and Access Management Functional Cluster (validation planned for R23-11)
With all these features already incorporated in Release 21-11, RTI’s efforts are currently focused on validation, vendor adoption and, of course, AUTOSAR’s Classic Platform.
Status of DDS in the AUTOSAR Classic Platform
In the past, DDS had sometimes been considered unsuitable for microcontroller-based Electronic Control Units (ECUs). This was mostly due to constraints on processing power, ROM and ROM footprint, which for decades have been measured in single-digit megahertz and kilobytes.
This trend has been changing for a few years now, thanks to the advent of the following factors:
- Increasingly powerful microcontroller designs, such as Infineon’s TC3xx and TC4xx lines (Tricore-based), or NXP’s S32Z and S32E lines (ARM-based)
- Central and Zonal microprocessor-based computers, where DDS clearly surpasses competing technologies such as SOME/IP or PDU-based communication
- Pervasive Ethernet connectivity across the vehicle (10,100,1000BASE-T1)
In this hardware environment, DDS implementations in the RTI Connext® product family such as Connext® Micro and the Connext® Cert add-on are a perfect match. Connext Micro is ported and validated (among other embedded real-time operating systems) to AUTOSAR Classic OS, while Connext Cert provides an ISO-26262 certification package.
But DDS still needs a way to further integrate into AUTOSAR’s Classic Platform, for which two initiatives have been rolled out over the past year:
- Standardization of a DDS Basic Software Module (BSwM) in the Classic Platform, led by Huawei and supported by RTI, targeting Send-Receive RTE communication semantics in R22-11
- RTI Connext Integration Toolkit for AUTOSAR Classic, a standards-based automatic coder for AUTOSAR Classic Send-Receive SW-C models
While standardization of the DDS BSwM will not be complete and validated until 2024 at the earliest, RTI’s Connext Integration Toolkit for AUTOSAR Classic is already available as part of Connext Drive® and has been tested on Vector’s MICROSAR and Elektrobit’s Tresos AUTOSAR product suites, with additional vendors in the works. It’s all part of RTI’s ongoing efforts to provide connectivity at the core, while helping automakers create tomorrow’s vehicles, today.
About the author
Emilio Guijarro is a software engineer with over 15 years of experience in the defense and automotive industries, including automotive infotainment systems. In 2019 he joined RTI to work on the integration of DDS in automotive use cases and in specific development environments, including the AUTOSAR ecosystem.