IoT Access Technoogy IEEE 802.15.4: ZigBee

The ZigBee protocol, developed in the late 1990s, was ratified in 2004 and has since grown to over 400 companies members of the ZigBee Alliance. 

 

The ZigBee Alliance is an industry group that focuses on certifying interoperability between vendors and driving the evolution of ZigBee as an IoT solution for connecting smart objects. ZigBee solutions are aimed at smart objects and sensors with low bandwidth and power needs.

 

ZigBee is most well-known in automation for commercial, retail, and home applications and smart energy. In industrial automation, ZigBee-based devices can handle various functions, such as measuring temperature and humidity, tracking assets, controlling lighting, thermostats, and security functions.

ZigBee uses the IEEE 802.15.4 standard at the lower PHY and MAC layers, with the network and security layer and application support layer specified on top of these layers. The network layer provides mechanisms for network startup, configuration, routing, and securing communications, while the application support layer interfaces the lower portion of the stack with higher-layer applications.

ZigBee predefines many application profiles for certain industries, and vendors can optionally create their own custom ones at this layer. While this structure has provided a fair degree of interoperability for vendors with membership in the ZigBee Alliance, it has not provided interoperability with other IoT solutions.

ZigBee employs Ad hoc On-Demand Distance Vector (AODV) routing within a mesh network. This routing system refrains from transmitting a message until a route is required. In the event that the subsequent hop for a route is absent from its routing table, a network node disseminates a request for a routing connection. This generates a surge of routing-related traffic; however, after evaluating several responses, the connection's optimal path with the fewest hops is identified. 

 

This technique markedly differs from conventional enterprise routing protocols, which typically acquire the whole network topology in some fashion and subsequently maintain a comprehensive yet consolidated routing table.

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