title: Designing an application protocol
body: <p>I have an existing standalone application which is going to be extended by a 3rd-party, using a network protocol. The capabilities are already implemented, all I need is to expose them to the outside.</p>
  
  <p>Assuming the transport protocol is already chosen (UDP), are there any resources that will help me to design my application protocol?</p>
  
  <p>There seems to be a lot of information about software design, but not on protocol design.
  I've already looked at <a href="http://www.faqs.org/docs/artu/ch05s03.html" rel="noreferrer">Application Protocol Design</a>.</p>