Except that DLNA has that third controller role that's usually taken over by either the client or the server, plus the confusion added by openhome servers with playlists (made even more confusing/annoying for me, since mine is provided by a fourth service/proxy, BubbleUPnP).

Standard DLNA is easy to remember, however, as long as you know the terms--[file]server, renderer, and controller. It even uses http for the fileserver (not sure if that's part of the standard or not though)