
Transmission, addressing, and routing
RF packet routing
XBee/XBee-PRO® S2C ZigBee® RF Module
91
0x00
Route options (set to 0)
0x02
Number of intermediate devices in the source route
0xCCDD
Address of furthest device (1-hop from target)
0xAABB
Address of next-closer device
0x5C
Checksum (0xFF - SUM (all bytes after length))
Repair source routes
It is possible for a network to have an existing source route fail (for example, a device in the route
moves or goes down). If a device goes down in a source routed network, all routes that used the
device will be broken.
As mentioned previously, source routing must be used with many-to-one routing. A device that uses
source routing must also send a periodic many-to-one broadcast in order to keep routes fresh. If a
source route breaks, remote devices send in new route record transmissions to the data collector to
provide it with a new source route. This requires that remote devices periodically send data
transmissions into the data collector. For more information, see
.
Retries and acknowledgments
ZigBee includes acknowledgment packets at both the Mac and Application Support (APS) layers. When
data transmits to a remote device, it may traverse multiple hops to reach the destination. As data
transmits from one node to its neighbor, an acknowledgment packet (Ack) transmits in the opposite
direction to indicate that the transmission was successfully received. If the transmitting device does
not receive the Ack, it retransmits the data up to 4 times. This Ack is called the Mac layer
acknowledgment.
In addition, the device that originated the transmission expects to receive an acknowledgment packet
(Ack) from the destination device. This Ack traverses the same path that the data traversed, but in the
opposite direction. If the originator fails to receive this Ack, it retransmits the data, up to two times
until an Ack is received. This Ack is called the ZigBee APS layer acknowledgment.
Note
Refer to the ZigBee specification for more details.
Disabling MTO routing
To disable MTO (many-to-one) routing in a network, first reconfigure the
AR
setting on the aggregator
and then broadcast a network wide power reset (0x08 of the
RE
command) to rebuild the routing
tables.
1. Set
AR
on the aggregator to 0xFF.
2. Complete an
AC
command to enact the change.
3. Complete a
WR
command if the saved configuration setting value for
AR
is not 0xFF.
This ends the periodic broadcast of aggregator messages if the previous setting was 0x01-0xFE, and
prevents a single broadcast after a power reset if the previous setting was 0x00. Broadcast a
FR
remote command to the network and wait for the network to reform. This removes the aggregator's
status as an aggregator from the network's routing tables so that no more route records will be sent
to the aggregator.
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Страница 259: ...AT commands Execution commands XBee XBee PRO S2C ZigBee RF Module 259 Parameter range N A Default N A ...
Страница 289: ...Regulatory information ANATEL Brazil XBee XBee PRO S2C ZigBee RF Module 289 ...
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Страница 303: ...Load ZigBee firmware on 802 15 4 devices Background 304 Load ZB firmware 305 XBee XBee PRO S2C ZigBee RF Module 303 ...