title: What is Assignable Unit in cmi5 spec?
body: <p>A bit introduction, I'm trying to create a LMS that will launch cmi5 course. But, I've trouble in understanding about cmi5 package and some other terms. Here I would like to ask/clarify several points to make it clear.</p>
  <p>I've seen TinCan/xAPI sample course/spec (I saw it <a href="https://github.com/RusticiSoftware/TinCan_Prototypes" rel="nofollow noreferrer">here</a>) and cmi5 spec <a href="https://github.com/AICC/CMI-5_Spec_Current/blob/quartz/cmi5_spec.md" rel="nofollow noreferrer">here</a>. I found out that they need different query string to launch the content.</p>
  <p>To be precised, in TinCan, for the authentication, we could pass <code>auth</code> query string and the <code>Basic {encoded username:password}</code> as the value (<a href="https://github.com/RusticiSoftware/launch/blob/master/lms_lrs.md" rel="nofollow noreferrer">here</a> is the reference). The <code>auth</code> then processed by the TinCanJS package (I'm using Javascript). But, in the cmi5 spec, it said to get the token, we could pass <code>fetch</code> query string and the value is our lms that return one time token only. The <code>fetch</code> url will called with <code>POST</code> method.</p>
  <p>But, I couldn't found &quot;where is the <code>fetch</code> value being processed in the cmi5 course?&quot; in the AU? I'm still confused with the terms of AU.</p>
  <ol>
  <li>Who will create it?</li>
  <li>How it looks like?</li>
  <li>is it included in the cmi5 course or do I have (as the creator of LMS) to create the AU?</li>
  </ol>
  <p>Thank you in advance.</p>