1. Peer-to-Peer (P2P) Networks By Bongju Yu

2. Contents  What is P2P?  Features of P2P systems  P2P Architecture  P2P Protocols  P2P Projects  Reference

3. What is P2P ?  P2P is Peer-to-Peer.  Sharing of computer resources and services by direct exchange between systems.  Resources including the exchange of information, processing cycles, cache storage, and disk storage for files.

4. Features of P2P systems  Distributed computing and resources  Collaboration  Intelligent agents  Core technologies

5. P2P Architecture  Computers that have been used as clients communicate directly among themselves and can act as both clients and servers.  Two basic models of P2P technology  Server dependant  True P2P

6. Server dependant  Considered as centralized since it holds a catalog of addresses.  The addresses are referenced by a set of indexes that determine the appropriate address set.  A classic example : Napster

8. True P2P  This type has every node as a Peer, and lacks a central router.  The routing structure either is a distributed catalog which uses indexes as parameters or direct messaging where the message is sent to a peer group until the inquiry is found.  The popular example : Gnutella

10. P2P Protocols  Connection Establishment  Search and Download  TTL (Time To Live)

11. P2P Projects  Napster  Scour  Gnutella  Freenet

12. Napster  The most popular P2P file-sharing program.  Lacking many of the advanced features of other P2P programs and limiting its file sharing capabilities to MP3 files only.  The first to be hit by lawsuits, Napster is still involved in legal battles.

13. Scour  Very popular with the second largest user base.  Users could share files of type MP3, video, and documents.  After the developments in Napster's case, and facing impending court cases, decided to shut down.

14. Gnutella  The first "true" P2P program.  Files of any type can be shared. To facilitate file sharing, messages are sent between end hosts.  Plagued with slow searches and a need for high bandwidth connections.

15. Freenet  Cannot be detected what files a user has downloaded or uploaded from the Freenet network.  Employing intelligent routing techniques superior to Gnutella.  If a user that was sharing files goes offline, his files remain available to download.

16. Reference 1.Geoffrey Fox, “Peer-to-Peer Networks”, Computing in Science & Engineering, Volume 3, Issue 3, Page 75 - 77, 2001. 2.Manoj Parameswaran, Anjana Susarla and Andrew B. Winston, “P2P Networking: An Information-Sharing Alternative”, Computer, Volume 34, Issue 7, Page 31 - 38, 2001. 3.Andy Oram, “Peer-To-Peer: Harnessing the Benefits of a Disruptive Technology”, O’Reilly & Associates, Inc., 2001. 4.David Wiley, “Peer-to-Peer and Learning Objects: the New Potential for Collaborative Constructivist Learning Online”, Proceedings IEEE International Conference on Advanced Learning Technologies, Page 494 - 495, 2001.

17. Thank you! End