Automatic Network-Aware Service Access

Although advances in wireless networks and the increasing availability of mobile end devices raise the prospect of ubiquitous access to network-based services, such access must cope with an inherent mismatch between the high bandwidth, relatively static connection requirements of many services and the low bandwidth, limited resource, and dynamic nature of mobile clients. In this paper, we describe an application-level programmable network infrastructure called CANS (Composable Adaptive Network Services), which alleviates this mismatch by enabling 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 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 scenarios, web access and image streaming, with client preferences for reduced response time and increased throughput respectively. Our results validate the effectiveness of the CANS approach for enabling network-aware service access to mobile clients, verifying that (1) automatic path creation and reconfiguration is achievable and desirable; and (2) that despite their flexibility, both path creation and reconfiguration can be supported with low run-time overhead.