OK, the idea of the REST WebService is, on one hand, to define/implement an API to manage p2psp channels: create a new channel, stream the content, list the existing channels, connect to an existing channel, etc...
manage also the streaming: one could create a channel and start sending the content with a POST
the server would start a splitter and pass that stream to it
a p2psp would query the server for that server and would get the URL of the splitter
and then, on another hand, the idea would be also to have a kind of Web interface to this API