1 An Extensible Interworking Architecture (EIA) for Wireless Sensor Networks and Internet Min Zhang, Sangheon Pack, Kideok Cho, Dukhyun Chang, Yanghee Choi, and Taekyoung Kwon Multimedia and Mobile Communication Laboratory School of Computer Science and Engineering Seoul National University, Seoul, Korea Email: {mzhang, shpack, kdcho, dhchang, yhchoi, tk}@mmlab.snu.ac.kr http://mmlab.snu.ac.kr/ Abstract One of representative applications of wireless sensor networks (WSNs) is a data collecting system that monitors and gathers physical phenomena in an area of interest. To build an end-to-end data collecting system, how to efficiently integrate WSNs with the Internet should be investigated. In this paper, we first present important design considerations regarding interworking between these two networks and review the existing interworking approaches: gateway-based and overlay-based approaches. Then, we propose a new interworking architecture, extensible interworking architecture (EIA), which forms overlay sensor networks (OSNs) over Internet. EIA employs two advanced functions to improve the data gathering efficiency: application layer graph (ALG) and distributed caching. Compared with previous works, EIA can meet the design requirements on the WSN/Internet interworking more efficiently.