No abstract

The transmission of voice-over-Internet protocol (VoIP) network traffic is used in an increasing variety of applications and settings. Many of these applications involve communications where VoIP systems are deployed under unpredictable conditions with poor network support. These conditions make it difficult for users to configure and optimize VoIP systems and this creates a need for self configuring and self optimizing systems. To build an autonomic system for VoIP communications, it is valuable to be able to measure the user perceived utility of a system. In this paper we identify factors important to the estimation of user perceived utility in task dependent VoIP communications.

We present a non-analytic approach to self-assessment for Autonomic Computing. Our approach leverages utility functions, at the level of an autonomic application, or even a single task or feature performed by that application. This paper describes the fundamental steps of our approach: instrumentation of the application; collection of exhaustive samples of runtime data about relevant quality attributes of the application, as well as characteristics of its runtime environment; synthesis of a utility function through statistical correlation over the collected data points; and embedding of code corresponding to the equation of the synthesized utility function within the application, which enables the computation of utility values at run time. We employ a number of case studies, with their results and implications, to motivate and discuss the significance of application-level utility, illustrate our statistical synthesis method, and describe our framework for instrumentation, monitoring, and utility function embedding/evaluation.