title: Tips about design/implementation of own protocol
body: <p>Where I work we are in need of a protocol capable of:</p>
  
  <ul>
  <li>User login/logout</li>
  <li>Send/recive instructions</li>
  <li>Send/recive files</li>
  <li>Send/recive audio stream(could use RTP)</li>
  <li>Send/recive small XML files Use</li>
  <li>cryptography for all those.</li>
  </ul>
  
  <p>It will be implemented in java. So I have some questions, since I´ve never implemeted a network protocol yet.</p>
  
  <ol>
  <li>Is it possible to use existing protocols to build this one?</li>
  <li>What tool can I use to help me design the protocol? for "Modeling"</li>
  <li>Is it possible to acomplish all this, doing it alone? I have as much time as I need for this.</li>
  </ol>
  
  <p>I have a pretty good background in Java and C++, but not yet with sockets/networking programming.</p>
  
  <p>Thanks</p>