title: How comes a TCP packet doesn't contains the source and destination IPs?
body: <p>From <a href="http://www.cisco.com/en/US/docs/internetworking/troubleshooting/guide/tr1907.html" rel="nofollow noreferrer">here</a> cisco says the TCP packets doesn't contains the source IP and destination IP?
  how the network layer knows tho thich IP send the packet and who has to get the ack back?</p>
  
  <p><img src="https://i.stack.imgur.com/3bE5L.jpg" alt="enter image description here"></p>