User Manual

XBee®/XBee‐PRO®RFModules‐802.15.4‐v1.xEx[2011.06.1]
©2011DigiInternatonal,Inc. 18
XBee®/XBee-PRO® Networks
The following terms will be used to explicate the network operations:
Peer-to-Peer
By default, XBee®/XBee-PRO RF Modules are configured to operate within a Peer-to-Peer network
topology and therefore are not dependent upon Master/Slave relationships. NonBeacon systems
operate within a Peer-to-Peer network topology and therefore are not dependent upon Master/
Slave relationships. This means that modules remain synchronized without use of master/server
configurations and each module in the network shares both roles of master and slave. Digi's peer-
to-peer architecture features fast synchronization times and fast cold start times. This default con-
figuration accommodates a wide range of RF data applications.
Figure2‐06. Peer‐to‐PeerArchitecture
A peer-to-peer network can be established by
configuring each module to operate as an End Device (CE = 0), disabling End Device Association
on all modules (A1 = 0) and setting ID and CH parameters to be identical across the network.
NonBeacon (w/ Coordinator)
A device is configured as a Coordinator by setting the CE (Coordinator Enable) parameter to “1”.
Coordinator power-up is governed by the A2 (Coordinator Association) parameter.
In a Coordinator system, the Coordinator can be configured to use direct or indirect transmissions.
If the SP (Cyclic Sleep Period) parameter is set to “0”, the Coordinator will send data immediately.
Otherwise, the SP parameter determines the length of time the Coordinator will retain the data
before discarding it. Generally, SP (Cyclic Sleep Period) and ST (Time before Sleep) parameters
should be set to match the SP and ST settings of the End Devices.
Table 2‐02. Termsanddefinitions
Term Definition
PAN
Personal Area Network - A data communication network that includes one or more End Devices and
optionally a Coordinator.
Coordinator
A Full-function device (FFD) that provides network synchronization by polling nodes [NonBeacon
(w/ Coordinator) networks only]
End Device
When in the same network as a Coordinator - RF modules that rely on a Coordinator for
synchronization and can be put into states of sleep for low-power applications.
Association
The establishment of membership between End Devices and a Coordinator. Association is only
applicable in NonBeacon (w/Coordinator) networks.