BinaryWS: Enabling the embedded web

The web is the most powerful paradigm on the Internet today. The widespread use of web services, almost universally in enterprise and Internet services, makes them very attractive for use in sensor networks as well. With the rapid expansion of IPv6 in sensor networks thanks to the 6LoWPAN standard, it is possible to implement web services suitable for very embedded nodes and networks. The SENSEI project makes use of web service concepts and a resource model to realize the SENSEI framework for the embedded web. This paper introduces Binary Web Services (BinaryWS), which enables end-to-end web services for even the most constrained devices and networks. Also, the paper analyzes several key schemes for encoding XML, which greatly reduce payload sizes. Results are given for the implementation of BinaryWS on Contiki and TinyOS sensor nodes, and for the comparison of XML encoding schemes for typical sensor network XML payloads. Results from an early experimental campaign proven the scalability of the approach. The combination of the BinaryWS protocol and the Efficient XML Interchange (EXI) standard are shown to be ideal for realizing the embedded web.