Learning Objectives

After successfully completing this section, you should be able to

  1. explain application protocols for file sharing.
  2. describe how P2P file sharing systems work.

Learning Tasks

Required:

  1. Watch the slideshow for this section.
  2. Study Section 2.5, Peer-to-Peer File Distribution, in the textbook.
  3. Search the Internet for peer churn. Select the two most interesting articles, read them, and post the links to the course forum along with your commentary.

Terms and Topics

Section 5 – Peer-to-Peer File Distribution

P2P file distribution
Scalability of P2P architectures
Distribution time
Minimum file distribution time
File distribution problem
BitTorrent
Rarest first

Unlocked peers
Optimistically unlocked peers
Distributed hash table (DHT)
Circular DHT
Overlay network
Peer churn

Leading Questions

  1. What is a peer-to-peer network application?
  2. What are the differences between client-server applications and peer-to-peer applications?
  3. How is P2P used for file distribution?
  4. Why is it said that P2P architecture is self-scalable?
  5. What is the file distribution problem?
  6. How is distribution time calculated for a P2P file distribution system?
  7. What does the BitTorrent system do?
  8. Where are distributed hash tables (DHTs) used?
  9. How does circular DHT work?
  10. What is an overlay network? How does it work?
  11. What does peer churn mean in P2P systems?