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.