Peer-to-Peer Networks as a Distribution and Publishing Model

1. Peer-to-Peer Networks as a Distribution and Publishing Model Jorn De Boever (june 14, 2007)

2. Outline of the presentation • Introduction • Characteristics and Challenges of Peer-to-Peer • Peer-to-Peer Applications • Classification of Peer-to-Peer Architectures • Peer-to-Peer Criteria and Openness • Discussion: Q&A

3. Introduction • Mass content distribution • Inefficient and costly. • Commercialization of internet • Mass medium. • Mostly client/server. • Foundation of peer-to-peer: penetration broadband internet, reliability of connections, capacity of user equipment, evolution compression technology, and etc. • Increasing demand for multimedia content. • Conclusion: traditional distribution models under pressure.

4. Outline of the presentation • Introduction • Characteristics and Challenges of Peer-to-Peer • Peer-to-Peer Applications • Classification of Peer-to-Peer Architectures • Peer-to-Peer Criteria and Openness • Discussion: Q&A

5. Characteristics and Challenges of Peer-to-Peer • Peer-to-peer principles • Sharing resources in a peer-to-peer manner • Partial or full decentralization • Self organizing systems depending on level of decentralization

6. Characteristics and Challenges of Peer-to-Peer • Peer-to-peer versus client/server • Client/server: • Easy to manage and control (centralized) • Negative network externalities: • limited scalability, • expensive distribution model, • danger for bottlenecks and single points of failure.

7. Characteristics and Challenges of Peer-to-Peer • Peer-to-peer versus client/server • Peer-to-Peer: • Scalability, decentralization, transient connectivity, cost efficiency, fault tolerance, self organization, resource sharing • Servents  SERVer + cliENTS • Positive network externalities: • Additional users = additional resources • Challenges: transient connectivity, security, availability of resources and scalability

8. Outline of the presentation • Introduction • Characteristics and Challenges of Peer-to-Peer • Peer-to-Peer Applications • Classification of Peer-to-Peer Architectures • Peer-to-Peer Criteria and Openness • Discussion: Q&A

9. Peer-to-Peer Applications • Communication: IM and Telephony • Grid computing • Collaborative applications • File sharing and content distribution • Wireless and ubiquitous peer-to-peer

10. Outline of the presentation • Introduction • Characteristics and Challenges of Peer-to-Peer • Peer-to-Peer Applications • Classification of Peer-to-Peer Architectures • Peer-to-Peer Criteria and Openness • Discussion: Q&A

11. Centralized Decentralized Hybrid Classification of Peer-to-Peer Architectures • Degree of decentralization • Centralized • Decentralized • Hybrid • Degree of structure • Unstructured • Structured

12. Server Query E D A B C D ? Download Classification of Peer-to-Peer Architectures • Centralized unstructured: e.g. Napster • Central directory server • Search process centralized (via server) • Exchange of data occurs in peer-to-peer manner

13. A QH B QH QH C D Classification of Peer-to-Peer Architectures • Pure decentralized unstructured: e.g. Gnutella 0.4 • No centralized component • Node functions: client, server, router, cache and search • Complete self organization

14. Classification of Peer-to-Peer Architectures • Hybrid unstructured: e.g. Gnutella 0.6 • Convergence: combining advantages and circumventing the drawbacks of centralized and pure decentralized systems. • Introducing hierarchy in the system via super nodes.

15. Classification of Peer-to-Peer Architectures • Pure decentralized structured: e.g. Chord • Self organizing without centralized components. • Structured: resources and nodes are mapped into address space. • Indexing of address space is distributed among nodes (DHT’s). • Advantages: • Efficient search mechanism • Disadvantages: • Updating routing tables causes load • Keyword-based search is not supported • Load balancing

16. Outline of the presentation • Introduction • Characteristics and Challenges of Peer-to-Peer • Peer-to-Peer Applications • Classification of Peer-to-Peer Architectures • Peer-to-Peer Criteria and Openness • Discussion: Q&A

17. Peer-to-Peer Criteria and Openness • When is a peer-to-peer solution appropriate? • Technical/business criteria • Cost of ownership. • Scalability. • Performance.  Peer-to-peer is a bandwidth saving distribution model and not a content model. • Social criteria: • Critical mass • Online available peers • Quantitative and qualitative availability

18. Peer-to-Peer Criteria and Openness • When is a peer-to-peer solution appropriate? • Peer-to-peer only appropriate for mass content distribution? What about small user communities? • Peer-to-peer might be possible if: • Peers have strong ties and similar interests. • Peers are simultaneously online enough. • Incentives to cooperate are provided.

19. Peer-to-Peer Criteria and Openness • When is a peer-to-peer solution appropriate? • Peer-to-peer and openness: open content, open access. • Content is free to users, distribution is expensive to content providers. • Existing systems: e.g. Lionshare, Comtella, Edutella. • Peer-to-peer appropriate for open initiatives if it meets peer-to-peer criteria. • If peer-to-peer is successful for open projects, storage and bandwidth costs will decrease. • Decreasing resource expenses reduce the barriers for open initiatives which can lead to more accessible content.

20. Outline of the presentation • Introduction • Characteristics and Challenges of Peer-to-Peer • Peer-to-Peer Applications • Classification of Peer-to-Peer Architectures • Peer-to-Peer Criteria and Openness • Discussion: Q&A

21. Discussion: Q&A • Conclusions • Peer-to-peer might provide solutions for some of the flaws of client/server networks. • Peer-to-peer is more than file sharing. • Classification based on degree of decentralization and structure. • Criteria for peer-to-peer solutions. • 2007: the year of the arrival of legal peer-to-peer systems?

22. Questions? Jorn De Boever – jorn.deboever@soc.kuleuven.be