GSN is a Java environment that runs on one or more computers composing the backbone of the acquisition network. A set of wrappers allow to feed live data into the system. Then, the data streams are processed according to XML specification files. The system is built upon a concept of sensors (real sensors or virtual sensors, that is a new data source created from live data) that are connected together in order to built the required processing path. For example, one can imagine an anemometer that would sent its data into GSN through a wrapper (various wrappers are already available and writing new ones is quick), then that data stream could be sent to an averaging mote, the output of this mote could then be split and sent for one part to a database for recording and to a web site for displaying the average measured wind in real time. All of this example could be done by editing only a few XML files in order to connect the various motes together.