Networking Reference
In-Depth Information
Likewise, results (sensor data) provided by the sensor nodes in response to the
received requests are sent back to the requesting applications as HTTP reply mes-
sages via the SIM_Web_Service class . When data produced by the sensor nodes in
a WSN is to be sent to a client in response to a given HTTP request, such data is
mapped into a REST compliant representation. Possible formats are HTML, XML
and JSON. This mapping is responsibility of the Driver class of the Communication
component .
4.2.1.2 Communication
Considering the WSN operation phases, this component includes the several classes
responsible for performing the phase (iii) data collection and delivery (see Sect. 3.2 ) .
FromtheHTTP requestmessages received and processed by the SIM_Web_Service
class , this component manages and distributes sensing tasks to the respective sensor
nodes, collects the received results and forwards them back to the Web server so that
they are properly delivered to the requesting application.
The Manager Class. The Manager class of the Communication component
directly interacts with the SIM_Web_Service class and determine, based on the analy-
sis of the incoming messages content and by querying the database maintained at
the gateway, which nodes are able to meet the received request (Fig. 4.3 ). The main
parameters used to perform the matching between a requested sensing task and the
nodes in a given WSN that are able to execute the task are (i) types of environmen-
tal variables to be monitored (depend on the sensing units available in the node);
(ii) geographical location of the node; and optionally (iii) quality of service (QoS)
Fig. 4.3 Simplified view of the interactions for the submission of application request messages;
message processing; and sensor data delivery
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