Address Table - Digi XBee 3 ZigBee User Manual

Transmission, addressing, and routing
destination, the Zigbee stack includes a discovery provision to automatically discover the destination
16-bit address of the device before routing the data.
To discover a 16-bit address of a remote, the device initiating the discovery sends a broadcast address
discovery transmission. The address discovery broadcast includes the 64-bit address of the remote
device with the 16-bit address being requested. All nodes that receive this transmission check the 64-
bit address in the payload and compare it to their own 64-bit address. If the addresses match, the
device sends a response packet back to the initiator. This response includes the remote's 16-bit
address. When the device receives the discovery response, the initiator transmits the data.
You can address frames using either the extended or the network address. If you use the extended
address form, set the 16-bit network address field to 0xFFFE (unknown). If you use the 16-bit network
address form, set the 64-bit extended address field to 0xFFFFFFFFFFFFFFFF (unknown).
If you use an invalid 16-bit address as a destination address, and the 64-bit address is unknown
(0xFFFFFFFFFFFFFFFF), the modem status message shows a delivery status code of 0x21 (network
ack failure) and a discovery status of 0x00 (no discovery overhead). If you use a non-existent 64-bit
address as a destination address, and the 16-bit address is unknown (0xFFFE), the device attempts
address discovery and the modem status message shows a delivery status code of 0x24 (address not
found) and a discovery status code of 0x01 (address discovery was attempted).

Address table

Each Zigbee device maintains an address table that maps a 64-bit address to a 16-bit address. When a
transmission is addressed to a 64-bit address, the Zigbee stack searches the address table for an
entry with a matching 64-bit address to determining the destination's 16-bit address. If the Zigbee
stack does not find a known 16-bit address, it performs address discovery to discover the device's
current 16-bit address.
64-bit address
0013 A200 4000 0001
0013 A200 400A 3568
0013 A200 4004 1122
0013 A200 4002 1123
The XBee 3 Zigbee RF Module supports up to 20 address table entries. For applications where a single
device (for example, coordinator) sends unicast transmissions to more than 10 devices, the
application implements an address table to store the 16-bit and 64-bit addresses for each remote
device. Use API mode for any XBee device that sends data to more than 10 remotes. The application
can then send both the 16-bit and 64-bit addresses to the XBee device in the API transmit frames
which significantly reduces the number of 16-bit address discoveries and greatly improves data
throughput.
If an application supports an address table, the size should be larger than the maximum number of
destination addresses the device communicates with. Each entry in the address table should contain a
64-bit destination address and its last known 16-bit address.
When sending a transmission to a destination 64-bit address, the application searches the address
table for a matching 64-bit address. If it finds a match, the application populates the 16-bit address
into the 16-bit address field of the API frame. If it does not find a match, set the 16-bit address to
0xFFFE (unknown) in the API transmit frame. The API provides indication of a remote device's 16-bit
address in the following frames:
Digi XBee® 3 Zigbee® RF Module
16-bit address
0x4414
0x1234
0xC200
0xFFFE (unknown)
Data transmission
98