Q: FAQ: Commissioning (Z-Stack, ZigBee)

Recommended method for provisioning a device when multiple PANs are operating in close range.

If you know the PAN_ID of the network you would like to join, as well as the channel it will operate on, you can set the ZDAPP_CONFIG_PAN_ID parameter to a specific PAN_ID, and the device will ONLY join a network with that PAN. The second way would be to set up an Access Control List on the Coordinator that has a list of allowed IEEE addresses. With security on, any device joining the network must get a key from the Coordinator, which will only distribute this key to devices that are in this list. This list can be populated dynamically (via commands to the Coordinator - either over the air or via some interface such as a Serial connection to another micro).

If you are unable to use security, ACL's, or pre-program a PAN_ID, your next option is to use some interface to the device (such as a button press), that temporarily puts the network into a state where it allows devices to join. Through the NLME_PermitJoiningRequest() interface you can turn joining on/off for a specific device. This could be called in response to a button press or a packet received over the air. Once joining is allowed, any device in the network searching for a network to join will then see a Beacon notifying the device that it is allowed to join, and will do so accordingly. However you have to remember that if there are multiple networks and some other network allows the device to join in the meantime, the device may already be established and may not be looking for a new network. In this respect you can program your device so that once it has joined a network it attempts to bind, and if it fails to find another point it can bind to then it initiates a leave and continues its process to find a suitable network.