Frequency Agility essentially means a network channel change. The channel change process is governed by a Network Manager device (typically the Coordinator), which changes the channel as decided by the application in response to incoming channel quality notifications.
A node will automatically notify the network manager (NM) when enough of its unicasts fail. Per Zigbee specifications, a report will be sent to the NM if all of the following conditions are met:
For the NM, the process is generally as follows: