Zigbee communication in depth

Zigbee is a global wireless standard that enables simple and smart objects to work together. This interoperability—multiple devices from different vendors working together to achieve a common goal—is one of the biggest advantages of using the Zigbee protocol.

 

Imagine that you want to automate your home to control the heating and cooling systems, lights, doors, blinds, irrigation system, etc. For these devices to interoperate, they need to "speak" the same language. Even if the light bulb was manufactured by Company A and the switch was manufactured by Company B, if they are Zigbee-certified products they can work together.

To achieve this interoperability among devices, the Zigbee protocol is organized in layers which separate the components and functions into independent modules. Each layer performs a specific set of services for the layer above.

As mentioned in the first topics of this guide, Zigbee is built on top of the IEEE 802.15.4 standard, so the bottom two layers (Physical Layer (PHY) and Medium Access Control Layer (MAC)) are from that specification. The Network Layer (NWK) from the Zigbee specification, which handles network structure, routing, and security, is just above the MAC layer.

Each layer plays an important role in the transmission of wireless data, but it is the Application Layer that enables interoperability. This layer consists of the Application Support Sublayer (APS), the Zigbee Device Object (ZDO), and the Application Framework.