title: How to get vehicle ID and type as unique Identifier from SUMO vehicle ID
body: <p>I'm use <strong>sumo</strong> 0.21.0 , <strong>omnet++</strong> 4.6 , and <strong>Veins</strong> 3.0
  I'm succeed in connecting my traffic mobility simulation (sumo) with network simulation (omnet++).
  I have flow of vehicle route in sumo rou file,</p>
  
  <pre><code> &lt;vType accel="2.0" decel="2.0" id="CarA" length="5.0" maxSpeed="15.0" minGap="2.5" sigma="0" vClass="passenger"/&gt;
  &lt;vType accel="2.0" color="0,1,0" decel="2.0" guiShape="bus" id="BUS" length="10" maxSpeed="12.0" minGap="2.5" sigma="0" speedDev="0.1" speedFactor="1.2" vClass="bus"/&gt;
  
  `&lt;flow begin="0" id="Bus1001" period="510" type="BUS" departSpeed="12" departLane="0"&gt;
      &lt;route edges="D1"/&gt;
      &lt;stop busStop="busstop1" duration="8.470000284081323"/&gt;
  &lt;/flow&gt;
  &lt;flow begin="0" color="0,0,1" id="car0" period="30" type="CarA" departSpeed="15" departLane="1"&gt;
      &lt;route edges="D1"/&gt;
  &lt;/flow&gt;`
  </code></pre>
  
  <p>and have 2 types of vehicle BUS and CarA.
  I want to use <strong>sumo vehicle ID</strong> as the nodes id in omnet++ and differentiate between vehicle car and bus.
  I read about adding <code>getExternalId()</code> but I can't find any clear and detail explanation how can it works, and how can I add those code in omnet++</p>