Packaging Quality of Service Control Behaviors for Reuse

Citation: Schantz RE, Loyall JP, Atighetchi M, Pal PP. Packaging Quality of Service Control Behaviors for Reuse. Proceedings of ISORC 2002, The 5th IEEE International Symposium on Object-Oriented Real-time distributed Computing, April 29 - May 1, 2002, Washington, DC.

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Abstract Two limitations of the current implementations of adaptive QoS behaviors are complexity associated with inserting them into common application contexts and lack of reusability across applications. What is needed is a way of bundling all the specification for systemic behavior into one place, and making it feasible to insert the collection of related QoS management artifacts into applications as a single, reusable behavior. As a means of addressing these issues, we have developed a new abstraction intended specifically to bundle together the lower level abstractions, specifications and implementations associated with providing adaptive QoS behaviors in a manner which is both easier to package, and makes the behavior bundle reusable in a variety of applications and styles of use. We call an integrated bundle of adaptive behavior specification and implementation a "qosket". In general, we see qoskets as the delivery vehicle for packaging the elements needed for supporting complex QoS attributes in an application independent manner. We envision an expanding set of prepackaged off-the-shelf behaviors developed by QoS specialists available to be bound with and perhaps customized for specific application contexts, making it relatively simple to include complex adaptive behavior in a wide array of distributed applications. Qoskets are a first step towards individual behavior packaging and reuse, as well as a significant step toward the more desirable (and much more complex) ability to compose behaviors within an application context. They are a means toward the larger goal of flexible design tradeoffs at runtime among properties such as real time performance, dependability and security, varying with current operating conditions. In this paper we introduce the concept of qoskets as reusable systemic behaviors, lay out elements of our design for qoskets within the QuO framework, and use a case study example to highlight the issues of using qoskets in practice.