Some of our customers have asked us for metrics that can be used to evaluate the quality of a given device's connection to their Zigbee network. For example, they would like to monitor all devices on the network and send an alert if a device has been moved out of range of its parent or placed in a challenging RF environment.
The Good News
Zigbee chip vendors typically provide access to LQI and RSSI data, which can be useful for evaluating these things.
Also, the Zigbee standards have been evolving to include more features such as the Diagnostics cluster, to enable the querying of LQI and RSSI data from other devices on the network.
The Tricky Part
It's difficult to come up with strict rules around "acceptable" values for LQI and RSSI. Consider a few factors:
MMB's Recommendations
If you are building a Coordinator, choose third-party devices with support for the Diagnostics cluster.
Install some Router devices, which serve as "repeaters" to improve the Zigbee mesh. Many mains-powered devices such as smart plugs will include this functionality. Talk to your MMB Account Manager to ask for suggestions that will work for your project.