title: What are some IP based protocols that don't use ports like TCP or UDP do?
body: <p>I'm learning about the Internet Protocol (IP) often referred to as TCP/IP. From what I understand, the Transport Control Protocol (TCP) is actually a totally different thing than IP. It's a layer on top of IP that does some more data integrity control. And, from what I understand, what is referred to as "ports", for example "port 80" for the HTTP protocol, is a TCP thing, not an IP thing.</p>
  
  <p><strong>So, what protocols that use the Internet Protocol under the hood don't use the notion of ports?</strong></p>
  
  <p>If you can link to open source software that implements such a protocol, that would be great.</p>