Wireless Ad Hoc and Sensor Networks

Task management planeMobility management planePower management planeBackground on Networking 39Application layerTransport layerNetwork layerData link layerPhysical layerFIGURE 1.7Sensor network protocol stack. (Reprinted from Akyildiz, I.F. et al., Computer Networks,Vol. 38, 393–422, 2002. With permission.)WINS (Pottie and Kaiser 2000), smart dust motes (Kahn et al. 1999), mAMPS(Akyildiz et al. 2002) use the protocol stack. This protocol stack combinespower and routing awareness, integrates data with networking protocols,communicates power efficiently through the wireless medium even in thepresence of mobility, and cooperating efforts among the sensor nodes.Depending on the sensing tasks, a variety of application software can bebuilt and used in the application layer. Common application managementprotocols include sensor management protocol (SMP), task assignment anddata advertisement protocol (TADAP), and sensor query and disseminationprotocol (SQDDP) (Akyildiz et al. 2002). Application level protocolsperform administrative tasks, such as rules for data aggregation, clusteringof nodes, exchanging location determination information, time synchronizationof the sensor nodes, mobility, ON/OFF feature, querying the sensornode configuration, and authentication, key distribution, and security.The transport layer helps maintain the flow of data, whereas the networkinglayer oversees the routing of data supplied by the transport layer.There are not many transport layer protocols for WSNs. Communicationbetween base station and sensor nodes are purely through UDP typeprotocols because each sensor node has limited memory. Protocols suchas TCP from computer networks cannot be used because sensor nodes donot have a global address. Instead, end-to-end schemes must considerattribute-based naming to indicate the destination. The power consumption,scalability, and data-centric routing makes sensor networks differentand they demand new types of transport layer protocols.