Requested Playlist Object
When a client connects to an on-demand publishing point and requests a playlist, the Windows Media server retrieves the associated file, parses it, and creates a playlist object that reflects the structure of the requested playlist. This is called the requested playlist object. The server uses the requested playlist object to determine the order in which content items must be streamed to the client. For example, assume that a client connects to your server by using the following URL.
mms://server_name/playlist.wsx
The server retrieves the playlist from the playlist.wsx file and uses a playlist parser plug-in to create a playlist object that reflects the structure of the file.