Peer-to-Peer Networks as a Distribution and Publishing Model Jorn De Boever (june 14, 2007)
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Transcript of Peer-to-Peer Networks as a Distribution and Publishing Model Jorn De Boever (june 14, 2007)
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.
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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
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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
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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.
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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
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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
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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
Classification of Peer-to-Peer Architectures
Degree of decentralization
Centralized
Decentralized
Hybrid
Degree of structure
Unstructured
Structured
Centralized Decentralized Hybrid
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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
B C D
E
A
ServerQuery
D
?
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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
A
B
C
D
QH
QH
QH
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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.
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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
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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
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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
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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.
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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.
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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?