Good UPnP documentation is available at at the website http://upnp.org. The architecture is described in the following document UPNP Device Architecture Document

A UPnP session exist of several steps: * 0. Addressing * 1. Discovery * 2. Description * 3. Control * 4. Eventing * 5. Presentation

upnpx is an implementation of the UPnP Specifications and has API functions for the different steps. This tutorial give simple examples how to use the upnpx API in order to build your own UPnP Control Point.

This tutorial handles the 6 individual steps and starts at Step 0. Addressing.