title: Is TCP bidirectional or full-duplex?
body: <p><code>Bidirectional</code> and <code>full-duplex</code> are different concepts. For example the <code>Ethernet</code> is only half-duplex because at a specific time, only one host can send data over the wire, and it cannot send and receive data <strong>simultaneously</strong>. </p>
  
  <p>So when we use TCP over an Ethernet, I think TCP is only bidirectional or half-duplex.</p>
  
  <p>But <a href="http://ssfnet.org/Exchange/tcp/tcpTutorialNotes.html">here</a> it says TCP is full-duplex. Why?</p>