Automatic creation and reconfiguration of network-aware service access paths

This paper describes an adaptive network infrastructure, Composable Adaptive Network Services (CANS), for bridging the bandwidth and resource gap between network services and mobile clients. CANS enables construction of service access paths augmented with ‘impedance matching’ components that handle operations such as caching, protocol conversion, and content transcoding. The CANS infrastructure focuses on the automatic creation and efficient dynamic reconfiguration of such network-aware access paths, relying upon three key mechanisms: (a) a high-level integrated type-based specification of components and network resources; (b) an automatic path creation strategy; and (c) system support for low-overhead path reconfiguration. We evaluate the CANS infrastructure over a range of network and end-device characteristics using two application scenario: web access and image streaming. Our results validate the effectiveness of the CANS approach for enabling network-aware service access to mobile clients, verifying that (1) communication paths automatically generated by CANS bring considerable performance advantages to applications; (2) desirable adaptation can be achieved using our flexible path creation mechanisms, which consider both underlying network conditions and different performance preferences of applications; and (3) despite their flexibility, both run-time overheads of CANS communication paths and reconfiguration time are negligible for most applications, providing applications with agile adaptation to dynamic changes in networks. q 2004 Elsevier B.V. All rights reserved.