Component-Based Dynamic QoS Adaptations in Distributed Real-Time and Embedded Systems

Abstract

Large scale distributed real time and embedded (DRE) applications are complex entities that are often composed of different subsystems and have stringent Quality of Service (QoS) requirements. These subsystems are often developed separately by different developers increasingly using commercial off-the shelf (COTS) middleware. Subsequently, these subsystems need to be integrated, configured to communicate with each other, and distributed. However, there is currently no standard way of supporting these requirements in existing COTS middleware. While recently emerging component-based middleware provides standardized support for packaging, assembling, and deploying, there is no standard way to provision QoS required by the DRE applications. We have previously introduced a QoS encapsulation model, qoskets, as part of our QuO middleware framework that can dynamically adapt to resource constraints. In this paper we introduce implementing these QoS behaviors as components that can be assembled with other application components. The task of ensuring QoS then becomes an assembly issue. To do so we have componentized our QuO technology instead of integrating QuO into the middleware as a service. To date, we have demonstrated our approach of QoS provisioning in MICO, CIAO, and Boeing’s Prism component middleware. We present experimental results to evaluate the overhead incurred by these QoS provisioning components in the context of CIAO CCM. We use a simulated Unmanned Aerial Vehicle (UAV) application as an illustrative DRE application for the demonstration of QoS adaptations using qosket components.

This work was supported by the Defense Advanced Research Projects Agency (DARPA) and Air Force Research Laboratory under contracts F33615-00-C-1694 and F33615-03-C-3317.