User's Manual

Table Of Contents
©2009DigiInternational,Inc. 43
4.DataTransmission,Addressing,andRout
ing
Addressing
All ZigBee devices have two different addresses, a 64-bit and a 16-bit address. The characteristics
of each are described below.
64-bit Device Addresses
The 64-bit address is a unique device address assigned during manufacturing. This address is
unique to each physical device. The 64-bit address includes a 3-byte Organizationally Unique
Identifier (OUI) assigned by the IEEE. The 64-bit address is also called the extended address.
16-bit Device Addresses
A device receives a 16-bit address when it joins a ZigBee network. For this reason, the 16-bit
address is also called the "network address". The 16-bit address of 0x0000 is reserved for the
coordinator. All other devices receive a randomly generated address from the router or coordinator
device that allows the join. The 16-bit address can change under certain conditions:
An address conflict is detected where two devices are found to have the same 16-bit address
A device leaves the network and later joins (it can receive a different address)
All ZigBee transmissions are sent using the source and destination 16-bit addresses. The routing
tables on ZigBee devices also use 16-bit addresses to determine how to route data packets
through the network. However, since the 16-bit address is not static, it is not a reliable way to
identify a device.
To solve this problem, the 64-bit destination address is often included in data transmissions to
guarantee data is delivered to the correct destination. The ZigBee stack can discover the 16-bit
address, if unknown, before transmitting data to a remote.
Application Layer Addressing
ZigBee devices can support multiple application profiles, cluster IDs, and endpoints. (See "ZigBee
Application Layers - In Depth" in chapter 3.) Application layer addressing allows data
transmissions to be addressed to specific profile IDs, cluster IDs, and endpoints. Application layer
addressing is useful if an application must
Interoperate with other ZigBee devices outside of the Digi application profile
Utilize service and network management capabilities of the ZDO
Operate on a public application profile such as Home Controls or Smart Energy.
The API firmware provides a simple yet powerful interface that can easily send data to any profile
ID, endpoint, and cluster ID combination on any device in a ZigBee network.
Data Transmission
ZigBee data packets can be sent as either unicast or broadcast transmissions. Unicast
transmissions route data from one source device to one destination device, whereas broadcast
transmissions are sent to many or all devices in the network.