DDS Gateway#

DDS-Gateway
status: valid
security: YES
safety: ASIL_B
tags: contribution_request, feature_request
realizes: wp__feat_request
doc__dds_gateway
Generic Document

Overview#

The DDS Gateway introduces a communication bridge within the S-CORE communication stack. It enables controlled and configurable data exchange between mw::com (LoLa) (intra-ECU communication via IPC binding) and DDS-based systems (inter-ECU communication), allowing integration with distributed DDS environments while preserving existing application implementations.

Architecture Concept#

The DDS Gateway acts as a centralized communication bridge between local mw::com (LoLa) communication and DDS domains, enabling inter-ECU communication between mw::com participants via DDS transport.

==============================        ==============================
           ECU 1                              ECU 2
==============================        ==============================

+-------------------------+           +-------------------------+
|     Application A       |           |     Application B       |
|   (mw::com LoLa)        |           |   (mw::com LoLa)        |
+-----------+-------------+           +-----------+-------------+
            |                                     ^
            |  mw::com (LoLa - IPC)               | mw::com (LoLa - IPC)
            v                                     |
    +---------------------+               +---------------------+
    |     DDS Gateway     |               |     DDS Gateway     |
    |       (ECU 1)       |               |       (ECU 2)       |
    +----------+----------+               +----------+----------+
               |                                     ^
               |                                     |
               v                                     |
      ===================   DDS NETWORK   ===================
               |                                     ^
   ==============================                    |
            ECU 3                                    |
   ==============================                    |
               |                                     |
               v                                     |
    +---------------------+                          |
    |   DDS Application   |--------------------------+
    |     (optional)      |
    +---------------------+

Each DDS Gateway instance connects to: - Local mw::com (LoLa) participants (IPC binding) - A DDS domain for inter-ECU communication

The gateway is responsible for:

  • Translating data in both directions between mw::com and DDS representations

  • Routing data across DDS domains

  • configure QOS on DDS for each route

  • Applying E2E protection

Scope#

The DDS Gateway provides:

  • Bridging between mw::com (LoLa) and DDS via the gateway:

    • mw::com (LoLa) → DDS GW → mw::com (LoLa) (inter-ECU communication via DDS)

    • mw::com (LoLa) → DDS GW → DDS applications

    • DDS applications → DDS GW → mw::com (LoLa)

  • Configurable routing:

    • Mapping between mw::com events(TBD for fields and methods) and DDS topics

    • Support for DDS domain-based routing

  • Dynamic Type handling:

    • Runtime type definition via configuration or via dynamic library

    • No dependency on DDS IDL generation

    • Enables data translation and consistent serialization across middleware boundaries

    • Supports DDS standard encodings (e.g., XCDR1 and XCDR2) for interoperability

  • End-to-End (E2E) protection:

    • Centralized handling of Counter, CRC, and DataID

    • Validation and protection configurable per route

  • DDS stack abstraction:

    • Pluggable DDS implementations via defined interfaces

  • Execution and performance model:

    • Asynchronous processing using internal worker queues

    • Support for configurable priority-based routing

    • High-priority routes can be processed with dedicated queues and worker pools to achieve low-latency data delivery

    • Normal-priority routes are handled via standard processing queues

    • Priority configuration is defined per route

  • DDS QoS configurability:

    • Ability to configure DDS Quality of Service (QoS) policies per route

    • Enables tuning of reliability, durability, and latency behavior based on use case

Motivation#

S-CORE currently focuses on local communication via mw::com (LoLa) but does not provide a standardized mechanism for inter-ECU communication using DDS-based systems.

In mixed middleware environments:

  • Integration with DDS requires custom adapters

  • Applications may need to embed DDS logic, reducing abstraction

  • Communication with native DDS applications is not standardized

  • Inter-ECU communication between mw::com participants via DDS is not standardized

  • Multi-domain DDS setups are difficult to manage consistently

The DDS Gateway addresses these challenges by introducing a centralized, configurable component responsible for bridging and routing communication across middleware boundaries.

Key Value#

  • Standardized integration with DDS systems

  • Direct interoperability with native DDS applications via the gateway

  • Standardized inter-ECU communication between mw::com participants via DDS

  • Clean separation between mw::com (LoLa) and DDS

  • Reduced integration effort

  • Support for distributed and multi-domain systems

  • Performance and determinism:

    • Low-latency processing for high-priority data flows

    • Controlled execution via configurable worker queues

    • Predictable behavior for mixed criticality communication

  • Interoperability across heterogeneous systems:

    • Enables communication between systems with different architectures (e.g., 32-bit / 64-bit, different endianness)

    • Ensures consistent data representation via Dynamic Type handling

  • Centralized handling of safety (E2E) and type management

Reference#

The detailed Feature Request is available here:

  • DDS Gateway Feature Request:https://github.com/eclipse-score/score/issues/2726