title: Tcp and receiving order
body: <p>I'm preparing an exam and I stumbled upon kind of interesting question. Basically what happens when for whatever reason the receiver receives the packets in reverse order?</p>
  
  <p>For example I have a window of size 2 and I send packet 2 and 3 but 3 arrives faster than 2.
  I'm not quite sure about the answer so I'll ask here.</p>
  
  <p>Does the receiver sends a duplicate ack upon arrival of 3 and then ack2 upon arrival of 2? </p>
  
  <p>And then, what happens to the transmission window?</p>