The use of peer-to-peer (P2P) networks for distributing content has been widely discussed in the last few years and the most important properties have been identified: scalability, efficiency and reliability. With CROSSFLUX we propose a P2P system for media streaming which incorporates these properties starting from the design. In addition reliability is coupled with fairness by rewarding peers that contribute more with a higher number of backup links. This coupling can be achieved by using links (1) for content distribution in one direction and (2) as backup in the opposite direction. For maximizing the throughput and distributing the load among the participating nodes an adaptive join procedure and reorganization algorithms are being used. Our evaluation of CROSSFLUX shows that recovery of node failures is fast and efficiency is increased with the help of our techniques.