1. A short overview of p2p technologies Marcelo Dias de Amorim Laboratoire LIP6 Université Pierre et Marie Curie http://www.lip6.fr/ Caen – Le 11 Juin 2003

2. IPv6 – Caen, 11 juin 20032 Plan  Introduction  Models  Example of applications  Some systems  References

3. IPv6 – Caen, 11 juin 20033 Definitions P2P is a class of applications that take advantage of resources – storage, cycles, content, human presence – available at the edges of the Internet. Clay Shirky ( www.shirky.com ) P2P refers to a class of systems and applications that employ distributed resources to perform a critical function in a decentralized manner. Milojicic et al. ( HP )

4. IPv6 – Caen, 11 juin 20034 Some controversy  Is p2p a new approach? Problems is peer-to-peer systems are neither new nor unique; they make us look for solutions to old problems that we all worked around or tried to ignore before. Andy Oram (O'Reilly & associates) speech at Free and Open Source Software Developers's Meeting Brussels, BE, Feb. 2002

5. IPv6 – Caen, 11 juin 20035 Curiosity (traffic) Others Unidentified P2P 18% 51% 31% One year ago… 48% 41% 11% … and today! source netflow.internet2.edu

6. IPv6 – Caen, 11 juin 20036 Properties  No central control, no central database  No hierarchy Every node is both a client and a server The communication between peers is symmetric  No global view of the system Scalablity  Availability for any peer  Peers are autonomous  System globally unreliable Robustness and security issues

7. IPv6 – Caen, 11 juin 20037 Examples of p2p usage  File-sharing applications  Distributed databases  Distributed computing (grid?)  Collaboration  Distributed games  Instant messaging  Ad hoc networks  Application-level multicast  Etc.

8. IPv6 – Caen, 11 juin 20038 IP Overlay networks Overlay

9. IPv6 – Caen, 11 juin 20039 Overlay networks IP Overlay

10. IPv6 – Caen, 11 juin 200310 Centralized model (Napster)  File-sharing system  Almost distributed system The location of a document is centralized The "transfer" is peer-to-peer  Problems Robustness Scalability (?)

11. IPv6 – Caen, 11 juin 200311 Centralized model (Napster) INTERNET location server register Document x? OK: Peer Z IP = a.b.c.d  Document x! x 

12. IPv6 – Caen, 11 juin 200312 Non-structured system (Gnutella-like)  Two phases (like Napster) Localization + exchange  No server  Open source gnutella.wego.com  Distributed search The query is flooded Loop avoidance Limited TTL (not all nodes are visited)

13. IPv6 – Caen, 11 juin 200313 Gnutella

14. IPv6 – Caen, 11 juin 200314 Structured systems (DHTs)  Based on distributed hash tables (DHTs)  No flooding Exact matches  Overhead Gnutella-like  O(n) DHT  O(log n)  Examples CAN, Pastry, Chord, Kademlia, Tapestry, etc.

15. IPv6 – Caen, 11 juin 200315 Content-Addressable Networks (CAN)  Provides a large scale distributed hash table Keys are mapped into values  CAN defines a d-dimensional virtual space No relationship with the physical space Query  O(n 1/d ) Neighbors  O(d)  The virtual space is completely distributed among the peers Each peer is responsible for one share of the space The peer that is responsible for region R is also responsible for the values inside R  Documents must be uniquely identified

16. IPv6 – Caen, 11 juin 200316 Example

17. IPv6 – Caen, 11 juin 200317 Example 1

18. IPv6 – Caen, 11 juin 200318 Example 12

19. IPv6 – Caen, 11 juin 200319 Example 2 1 33

20. IPv6 – Caen, 11 juin 200320 Example 2 3 14

21. IPv6 – Caen, 11 juin 200321 Example 2 3 14 5 4

22. IPv6 – Caen, 11 juin 200322 Example 2 3 6 4 5 1

23. IPv6 – Caen, 11 juin 200323 Example 2 3 6 4 5 17

24. IPv6 – Caen, 11 juin 200324 Association ID  node 2 3 6 4 5 17 Ex: Node 3 holds this document

25. IPv6 – Caen, 11 juin 200325 Association ID  node 2 3 6 4 5 17

26. IPv6 – Caen, 11 juin 200326 Application-layer multicast  Native multicast  not yet completely deployed  ALM  easier/faster to implement Scalability  states at end-systems High-level support

27. IPv6 – Caen, 11 juin 200327 Application-layer multicast source

28. IPv6 – Caen, 11 juin 200328 Taxonomy P2P Applications Compute Intensive Compo- nentized Content exchange File system Filtering, mining Instant message Shared apps Games Parallel Content and file mngt Collaboration

29. IPv6 – Caen, 11 juin 200329 Many works and projects  Gnutella and Napster @sourceforge.net

30. IPv6 – Caen, 11 juin 200330 JXTA (Sun)  Open platform for p2p cooperation  Interoperability Any system/peer/application  Platform independency Languages (C, Java, etc) Systems platforms (Unix, Windows, etc) Networking platforms (802.11, Bluetooth, TCP/IP, etc)  Ubiquity Sensors, PDAs, routers, desktops, laptops, storage systems

31. IPv6 – Caen, 11 juin 200331 JXTA (Sun)  Objectives Find peers and resources Share files with anyone across the network Create a particular group of peers across different networks Communicate securely with peers across public networks  Projects Applications (24 projects) Core (13 projects) Demos (3 projects) Forge (15 projects) Other (12 projects) Services (24 projects)

32. IPv6 – Caen, 11 juin 200332 JXTA (Sun)  Protocols  Peer discovery protocol  Peer resolver protocol  Peer information protocol  Rendezvous protocol  Pipe binding protocol  Endpoint routing protocol

33. IPv6 – Caen, 11 juin 200333 JXTA (Sun) Peer (Desktop, cell phone, PDA, etc.) Security Peer GroupsPeer PipesPeer Monitoring JXTA Community Services Sun JXTA Services JXTA Shell Peer Commands JXTA Community Applications CORECORE JXTAJXTA

34. IPv6 – Caen, 11 juin 200334 JXTA applications

35. IPv6 – Caen, 11 juin 200335 Final remarks  P2P implies a very large spectrum of areas  High interest in both academicals/industrials  Much has already been done, but no conclusions are definitive  IPv6 and P2P NAT, firewalls, IPv6 as an overlay  Many open issues Trust, security, scalability, QoS, etc.

36. IPv6 – Caen, 11 juin 200336 Working groups et al.  A generic site on p2p from O'Reilly www.openp2p.com  P2P working group www.peer-to-peerwg.org/  Internet2 p2p working group p2p.internet2.edu  Peer-to-peer development (p2p-hackers) zgp.org/mailman/listinfo/p2p-hackers  Interesting meeting www.codecon.org

37. IPv6 – Caen, 11 juin 200337 References  Distributed Computing Distributed (www.distributed.net)www.distributed.net SETI@home (www.seti.org)www.seti.org Genome@home (gah.stanford.edu) Folding@home (www.stanford.edu/group/pandegroup/folding) Global Grid Forum (www.globalgridforum.org)www.globalgridforum.org Globus Project (www.globus.org)www.globus.org  File sharing Napster (www.napster.com)www.napster.com Gnutella (gnutella.wego.com) Kazaa (www.kazaa.com)www.kazaa.com

38. IPv6 – Caen, 11 juin 200338 References  Distributed hash tables CAN (www.acm.org/sigs/sigcomm/sigcomm2001/p13- ratnasamy.pdf) Pastry (research.microsoft.com/~antr/Pastry) Chord (www.pdos.lcs.mit.edu/chord)www.pdos.lcs.mit.edu/chord Tapestry (www.cs.berkeley.edu/~ravenben/tapestry)www.cs.berkeley.edu/~ravenben/tapestry Freenet (freenet.sourceforge.net) Kademlia (kademlia.scs.cs.nyu.edu)  Ad hoc networking AODV (www.ietf.org/internet-drafts/draft-ietf-manet- aodv-13.txt) OLSR (www.ietf.org/internet-drafts/draft-ietf-manet-olsr- 10.txt) Tribe (rp.lip6.fr/site_rp/_publications/350-79Viana.ps.gz)

39. IPv6 – Caen, 11 juin 200339 References  Platforms JXTA (www.jxta.org)www.jxta.org.NET (www.microsoft.com/net)www.microsoft.com/net  Collaboration Groove (www.groove.net)www.groove.net Endeavors (www.endeavors.com)www.endeavors.com  IPv6 as a p2p overlay  Working Groups p2p.internet2.edu www.openp2p.com