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XBee Series 2 OEM RF Modules ‐ ZigBee ‐ v1.x2x [2007.07.019]
3.2. ZigBee Network Communications
3.2.1. ZigBee Device Addressing
3.2.2. ZigBee Application-layer Addressing
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Zigbee supports device addressing and application layer addressing. Device addressing specifies
the destination address of the device a packet is destined to. Application layer addressing indicates
a particular application recipient, known as a Zigbee endpoint, along with a message type field
called a Cluster ID.
The 802.15.4 protocol upon which the ZigBee protocol is built specifies two address types:
• 16-bit network addresses
• 64-bit Addresses
16-bit Network Addresses
A 16-bit network address is assigned to a node when the node joins a network. The network
address is unique to each node in the network. However, network addresses are not static - it can
change.
The following two conditions will cause a node to receive a new network address:
1.
If an end device cannot communicate with its parent it may need to leave the network and
rejoin to find a new parent.
2.
If the device type changes from router to end device, or vice-versa, the device will leave
the network and rejoin as the new device type.
ZigBee requires that data be sent to the 16-bit network address of the destination device. This
requires that the 16-bit address be discovered before transmitting data. See 3.2.3 Network
Address Discovery for more information.
64-bit Addresses
Each node contains a unique 64-bit address. The 64-bit address uniquely identifies a node and is
permanent.
The ZigBee application layers define endpoints and cluster identifiers (cluster IDs) that are used to
address individual services or applications on a device. An endpoint is a distinct task or application
that runs on a ZigBee device, similar to a TCP port. Each ZigBee device may support one or more
endpoints. Cluster IDs define a particular function or action on a device. Cluster IDs in the ZigBee
home controls lighting profile, for example, would include actions such as "TurnLightOn",
"TurnLightOff", "DimLight", etc.
Suppose a single radio controls a light dimmer and one or more light switches. The dimmer and
switches could be assigned to different endpoint values. To send a message to the dimmer, a
remote radio would transmit a message to the dimmer endpoint on the radio. In this example, the
radio might support cluster IDs to "TurnLightOn", "TurnLightOff", or "DimLight". Thus, for radio A to
turn off a light on radio B, radio A would send a transmission to the light switch endpoint on radio
B, using cluster ID "TurnLightOff". This is shown in the figure below.
© 2007 Digi International, Inc.
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Chapter 3 ‐ ZigBee Networks
19
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