title: Is there a way to know that the node is disconnected/out of the RPL network in contiki 3.0?
body: <p>I have a mobility node that moved out of the range of the RPL network. I need to know that this node is out of the network range.
  I tried this code:</p>
  <pre><code>if (rpl_neighbor_count() == 0) {
      printf(&quot;NO NEIGHBORS\n&quot;); 
  }
  else {
      printf(&quot;There are NEIGHBORS \n&quot;);
  }
  </code></pre>
  <p>However, the count doesn't update when the movement of the node happens and it remains as it was before and it is the same all the time.</p>