
ZigBee networks
ZigBee networking concepts
XBee/XBee-PRO® S2C ZigBee® RF Module
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ZigBee layer Descriptions
PHY
Defines the physical operation of the ZigBee device including receive sensitivity,
channel rejection, output power, number of channels, chip modulation, and
transmission rate specifications. Most ZigBee applications operate on the 2.4 GHz
ISM band at a 250 kb/s data rate. See the IEEE 802.15.4 specification for details.
MAC
Manages RF data transactions between neighboring devices (point to point). The
MAC includes services such as transmission retry and acknowledgment
management, and collision avoidance techniques (CSMA-CA).
Network
Adds routing capabilities that allows RF data packets to traverse multiple devices
(multiple hops) to route data from source to destination (peer to peer).
APS (AF)
Application layer that defines various addressing objects including profiles, clusters,
and endpoints.
ZDO
Application layer that provides device and service discovery features and advanced
network management capabilities.
ZigBee networking concepts
Device types
ZigBee defines three different device types: coordinator, router, and end device.
Coordinator
ZigBee networks always have a single coordinator device. This device:
n
Starts the network, selecting the channel and PAN ID (both 64-bit and 16-bit).
n
Distributes addresses, allowing routers and end devices to join the network. Assists in routing
data.
n
Buffers wireless data packets for sleeping end device children.
n
Manages the other functions that define the network, secure it, and keep it healthy. Cannot
sleep; the coordinator must be powered on all the time.
Router
A router is a full-featured ZigBee node. This device:
n
Can join existing networks and send, receive, and route information. Routing involves acting as
a messenger for communications between other devices that are too far apart to convey
information on their own.
n
Can buffer wireless data packets for sleeping end device children. Can allow other routers and
end devices to join the network.
n
Cannot sleep; router(s) must be powered on all the time.
n
May have multiple router devices in a network.