Address Table - Digi XBee-PRO S2C Zigbee User Manual

Transmission, addressing, and routing
is obtained after joining a network. The 16-bit address can also change under certain conditions.
When sending a unicast transmission, the Zigbee network layer uses the 16-bit address of the
destination and each hop to route the data packet. If you do not know the 16-bit address of the
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 network address field to 0xFFFE (unknown). If you use the network address
form, set the 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
For the Smart Energy profiles and related firmware, the XBee devices can store up to 10 address table
entries. For the standard firmware versions, the 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
XBee/XBee-PRO® S2C Zigbee® RF Module
16-bit address
0x4414
0x1234
0xC200
0xFFFE (unknown)
Data transmission
77