Figure 2 shows how the watchdog system used by ADIOS
works. Node S wants to send some data to Node D via nodes A,
B and C. Node A does not have enough power to transmit all
the way to Node C so it transmits to Node B as an intermediary.
Although Node A is out of the radio range of Node C, it is
usually able to overhear what Node B sends to Node C since Node B is still within its reception range. It is important to
note that due to physical characteristics of the transmission
medium or lower layer collisions, not all transmissions from
B to C will be heard by A all the time.