.......................<a href="#page-21">21</a>
     <a href="#section-17.2">17.2</a>. Informative References...................................<a href="#page-21">21</a>
  <a href="#section-18">18</a>. Authors&#39; addresses............................................<a href="#page-22">22</a>


<span><a name="section-1" href="#section-1">1</a>.  Introduction</span>

    Many services for data storage are available over the internet. This
    specification describes a vendor-independent interface for such
 