Supporting end-to-end quality of service properties in OMG data distribution service publish/subscribe middleware over wide area networks

• We demonstrate how DDS scheduling overhead contributes to processing delays.
• The evaluation of the architecture shows that proposed QoS approach shows how DDS services enhance the schedulability and the predictability of DRE applications.
• The framework improves data delivery over heterogeneous IP networks, and confirms its potential impact providing network-level differentiated performance.
• We examine how DDS QoS mechanisms impact bandwidth protection in WANs.
• The customized implementations of DDS can achieve lower end-to-end delay.

Assuring end-to-end quality-of-service (QoS) in distributed real-time and embedded (DRE) systems is hard due to the heterogeneity and scale of communication networks, transient behavior, and the lack of mechanisms that holistically schedule different resources end-to-end. This paper makes two contributions to research focusing on overcoming these problems in the context of wide area network (WAN)-based DRE applications that use the OMG Data Distribution Service (DDS) QoS-enabled publish/subscribe middleware. First, it provides an analytical approach to bound the delays incurred along the critical path in a typical DDS-based publish/subscribe stream, which helps ensure predictable end-to-end delays. Second, it presents the design and evaluation of a policy-driven framework called Velox. Velox combines multi-layer, standards-based technologies—including the OMG DDS and IP DiffServ—to support end-to-end QoS in heterogeneous networks and shield applications from the details of network QoS mechanisms by specifying per-flow QoS requirements. The results of empirical tests conducted using Velox show how combining DDS with DiffServ enhances the schedulability and predictability of DRE applications, improves data delivery over heterogeneous IP networks, and provides network-level differentiated performance.