ABSTRACT
In this chapter, we examine a number of unstructured P2P overlay networks. Many of these solutions can be seen to be part of the first generation of P2P and overlay networks; however, they also can be combined with structured approaches to form hybrid solutions. We cover protocols such as Gnutella, BitTorrent, and Freenet and present a comparison of them. This chapter places special emphasis on BitTorrent, because it has become the most frequently used P2P protocol.
