A Configurable Middleware Framework for Small Embedded Systems that Supports Multiple Quality of Service Properties

The majority of microprocessors manufactured in recent years have been deployed in embedded systems, often with real-time requirements, and increasingly they are being networked. Middleware frameworks offer many advantages to distributed systems designers and application programmers. However, there are very few middleware frameworks that are suitable for the low end of the embedded systems market, and they are only coarsely configurable. Furthermore, even fewer middleware frameworks of any size support multiple Quality of Service properties, such as fault tolerance, security, and timeliness. In this paper we describe the design and implementation of MicroQoSCORBA. It represents a fundamental, bottom-up rethinking of what middleware can and should support for resource-constrained devices. This framework can be tailored, with a fine degree of granularity, to both device and application program constraints. This paper also describes the architectural taxonomy that was developed to specify and implement these constraints, the multiple Quality of Service domains that MicroQoSCORBA supports, and it presents an evaluation of our working framework. Our evaluation results illustrate the need to balance tradeoffs between application design, hardware resource constraints, and desired levels of multiple Quality of Service constraints.