
Transmission, addressing, and routing
Maximum RF payload size
XBee/XBee-PRO® S2C ZigBee® RF Module
93
high, the message fragments into a maximum of five fragments. The firmware encrypts and transmits
each fragment separately. The destination radio reassembles the fragments into a full message.
For Smart Energy firmware revision 5x32 and earlier,
NP
==0x80. As of 5x56,
NP
==0xFF.
The maximum payload is complicated to estimate for aggregator source-routing. To reduce the
maximum payload, when an aggregator sends a source-routed message it embeds the route into the
message as overhead, or into each fragment of the message, if fragmentation is necessary. If you use
APS encryption (EE1, Tx Option 0x20), it reduces the number further.
The route overhead is 2 bytes plus 2 bytes per hop. The bytes are:
n
one byte is the number of hops
n
one byte is an index into the route list that increments in value at each hop
n
other data is a list of the 16-bit network addresses of the routing radios
Firmware revisions before 4x58 support a maximum of 11 aggregator source-routed hops. Firmware
revisions 4x58 and following support a maximum of 25 aggregator source-routed hops.
Aggregator source-routed payload maximums do not apply to messages that are sourced by non-
aggregator nodes, which send route records ahead of their messages to aggregators. Aggregators
are either Coordinators or Routers which have the following:
n
Source routing enabled or
n
AR
setting which is not 0xFF
The following table shows the aggregator source-routed payload maximums as a function of hops and
APS encryption:
Hops
Maximum encrypted payload
Maximum unencrypted payload
1
255
255
2
255
255
3
255
255
4
255
255
5
255
255
6
215
255
7
205
250
8
195
240
9
185
230
10
175
220
11
165
210
12
155
200
13
145
190
14
135
180
15
125
170
Содержание XBee
Страница 1: ...XBee XBee PRO S2C ZigBee RF Module User Guide ...
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 ...
Страница 290: ...Regulatory information ANATEL Brazil XBee XBee PRO S2C ZigBee RF Module 290 ...
Страница 303: ...Load ZigBee firmware on 802 15 4 devices Background 304 Load ZB firmware 305 XBee XBee PRO S2C ZigBee RF Module 303 ...