title: How do Apple devices discover each other on a local network?
body: <p>How do Apple devices discover each other on a local network?</p>
  
  <p>For example, iTunes running on my laptop is able to discover my iPhone when my iPhone is on my local network's wifi and iTunes then communicates with my iPhone. How does it do this?</p>
  
  <p>I'm looking for low-level details. Since this question concerns closed-source software, I can't expect an answer that points me to source code but since the question also concerns popular devices and interaction over a network which can be monitored, I'm hoping that relatively low-level details are known. A good answer should give enough information that someone with modest knowledge in network programming could understand it and fill in the blanks.</p>