Adaptive Service Access in Shared Wireless Environments Xiaodong Fu, Vijay Karamcheti TR2001-824 March 15, 2002 Adaptation to network changes is important to provide applications with seamless service access in a shared wireless environment. Path-based mechanisms, which augment data paths with application-specific ``bridging'' components guided by minimal application input, are promising approaches for providing such support. Although shown to be successful in static network situations, their utility under dynamically changing network conditions has not been well-studied. In this paper, we answer this question by investigating the performance of a path-based approach, CANS (Composable Adaptive Network Services) in a dynamic environment. We find that the suitability of CANS-like approaches is hampered by inaccurate component models and expensive planning and reconfiguration. We address these problems by extending CANS to support (1) generalized path creation strategies to match different application performance preferences; (2) refined component models that enable adjustment at a finer granularity and more accurately represent behavior of component compositions; and (3) local planning and reconfiguration mechanisms that improve responsiveness. We present the problems and evaluate our solutions using an image streaming application. The experiment results show that our solutions are effective.