PeertoPeer Content Sharing P 2 P File Sharing

Peer-to-Peer Content Sharing

P 2 P File Sharing Benefits • Why use a P 2 P model for a file sharing application?

Research Areas • • Peer discovery and group management Data placement and searching Reliable and efficient file exchange Security/privacy/anonymity/trust

Design Concerns • Group Management – Per-node state – Load balancing – Fault tolerance/resiliency • Search – – Bandwidth usage Time to locate item Success rate Fault tolerance/resiliency

Approaches • Centralized • Unstructured • Structured (Distributed Hash Tables)

Centralized Bob Alice • Napster model • Benefits: • Drawbacks: Judy Jane

Centralized Bob Alice • Napster model • Benefits: – – – Low per-node state Limited bandwidth usage Short location time High success rate Fault tolerant • Drawbacks: – Central point of failure – Limited scale – Possibly unbalanced load Judy Jane

Unstructured Carl Jane • Gnutella model • Benefits: • Drawbacks: Bob Alice Judy

Unstructured Carl Jane • Gnutella model • Benefits: – Limited per-node state – Fault tolerant • Drawbacks: – – High bandwidth usage Long time to locate item No guarantee on success rate Possibly unbalanced load Bob Alice Judy

Structured 001 • Free. Net, Chord, CAN, Tapestry, Pastry model • Benefits: • Drawbacks: 012 212 ? 332 212 305

Structured 001 012 • Free. Net, Chord, CAN, Tapestry, Pastry model • Benefits: – Manageable per-node state – Manageable bandwidth usage and time to locate item – Guaranteed success • Drawbacks: – Possibly unbalanced load – Harder to support fault tolerance 212 ? 332 212 305

Improvements: Super. Peers • Ka. Za. A model • Hybrid centralized and unstructured • Advantages and disadvantages?

Other Improvements • Caching indices – Push vs pull • Building communities/directed search • Replication of content – Enables load balancing – how?