Performance Evaluation And Comparison Of Routing Algorithms In Zigbee/ Ieee 802.15.4
P. M. Anitha · i-manager’s Journal on Software Engineering · 2010
ZigBee defines two layers of the OSI (Open Systems Interconnection) model: the Application Layer (APL) and the Network Layer (NWL). Each layer performs a specific set of services for the layer above. The different layers communicate through Service Access Points (SAPs). These SAPs enclose two types of entities: (1) a data entity (NLDE-SAP) to provide data transmission service and (2) a management entity (NLME-SAP) to provide the management services between layers. The ZigBee Network Layer (NWK) is responsible for Network management procedures (e.g., nodes joining and leaving the network, security and routing). It also encloses the neighbor tables and the storage of related information. The NWK Layer provides one set of interfaces, the Network Layer Data Entity Service Access Point (NLDE-SAP)is used to exchange data with the SAP. IEEE 802.15.4/ZigBee devices can be classified based on their functionalities: They are, Full Function Devices (FFD) implementing the full IEEE 802.15.4/ZigBee protocol stack, Reduced Function Devices (RFD) implementing a subset of the protocol stack. Regarding the devices role in the network, ZigBee defines 3 types of devices: ZigBee Coordinator (ZC) which is One for each ZigBee Network, initiates and configures Network formation, Acts as an IEEE 802.15.4. Personal Area Network (PAN) Coordinator, acts as ZigBee Router (ZR) once the network is formed, and is a Full Functional Device (FFD) implementing the full protocol stack. If the network is operating in beacon-enabled mode, the ZC will send periodic beacon frames that will serve to synchronize the rest of the nodes. The ZigBee Network Layer [3] is responsible for network management (e.g., association/disassociation, starting the network, addressing, device configuration and the maintenance of the NIB -network Information Base) and formation, message routing and security-related services. The ZigBee Network Layer supports two service entities [4] . NLDE provides a data service, allowing the