Digi XBee Zigbee Mesh Kit User Manual page 182

Large networks routing
1. The microcontroller application must force the XBee to create a source route in its internal source
route table by sending a Create Source Route (0x21) frame through the serial interface.
2. After setting up the source route, the application can send data to be wirelessly transmitted
(Transmit Request (0x10), Explicit Addressing Command Frame (0x11), or Remote Command
Request (0x17) frames) as needed, to the same destination, or any destination in the established
source route.
3. If new data must be sent to a destination not included in the last source route, the application
must first send a new Create Source Route API frame.
Note If a Create Source Route API frame (0x21) does not precede data frames, data loss may occur.
XBee modules can buffer one source route that includes up to 11 hops (excluding source and
destination).
When source routing is used, the 16-bit addresses in the source route are inserted into the RF payload
space. This means the payload will be reduced by two bytes per intermediate hop. The user must
account for the payload size reduction when using source routing.
XBee® Zigbee® Mesh Kit
Source routing
182