1What is the Zigbee network protocol? The Simplest View for IOT applications.

Firstly, the Zigbee communications protocol connects low power devices in a personal area network. In addition, Zigbee technology is ideal in an IOT environment where the devices are battery powered. These devices with an attached sensor need to work and communicate in a low power environment.
IOT applications such as home automation and AMR smart metering typically use the Zigbee technology protocol.
2What exactly is the Zigbee wireless communications protocol: The OSI protocol view.

The best way to understand the Zigbee communications protocol is to use the OSI model.
Lets start with the IEEE 802.15.4 Specification. The IEEE 802.15.4 specification (couldnt there be a shorter name!) is a standard for the first two layers. These are the physical and the MAC layers.
Zigbee specifies the communications protocol for all the above layers – from layer 3 and above.
OSI Layer | Protocol/Standard |
---|---|
Physical Layer: Layer 1 | IEEE 802.15.4 |
MAC Layer: Layer 2 | IEEE 802.15.4 |
Networking Layer: Layer 3 | Zigbee Protocol |
Transport Layer: Layer 4 | Zigbee Protocol |
Session Layer: Layer 5 | Zigbee Protocol |
Presentation Layer: Layer 6 | Zigbee Protocol |
Applications Layer: Layer 7 | Zigbee Protocol |