Addressing

All Zigbee devices have two different addresses, a 64-bit and a 16-bit address. This section describes the characteristics of each.

64-bit device addresses

The 64-bit address is a device address which is unique to each physical device. It is sometimes also called the MAC address or extended address and is assigned during the manufacturing process. The first three bytes of the 64-bit address is a Organizationally Unique Identifier (OUI) assigned to the manufacturer by the IEEE. The OUI of XBee devices is 0x0013A2.

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 support multiple application profiles, cluster IDs, and endpoints (for more information, see Zigbee application layers: in depth). 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 do any of the following:

• Interoperate with other Zigbee devices outside of the Digi application profile.
• Use service and network management capabilities of the ZDO.
• Operate on a public application profile such as Home Automation or Smart Energy.

API mode provides a simple yet powerful interface that easily sends data to any profile ID, endpoint, and cluster ID combination on any device in a Zigbee network.