CPSC 426/526. P2P Lookup Service. Ennan Zhai. Computer Science Department Yale University

Transcription

1 CPSC / PP Lookup Service Ennan Zhai Computer Science Department Yale University

2 Recall: Lec- Network basics: - OSI model and how Internet works - Socket APIs red PP network (Gnutella, KaZaA, etc.) UseNet and gossip protocol: - UseNet format and peer identity - How gossip protocol runs, pros. and cons. Structured PP network (Chord, CAN, Pastry, etc.) - More (Hybrid PP, BitTorrent, etc.)

3 Lecture Roadmap Background Chord Design Evaluating Chord Comparison

4 Background History of Peer-to-Peer (PP) systems: - Napster, the first PP content sharing system - Unstructured PP network (Gnutella, KaZaA, etc.) - Structured PP network (Chord, CAN, Pastry, etc.) - More (Hybrid PP, BitTorrent, etc.)

5 Background History of Peer-to-Peer (PP) systems: - Napster, the first PP content sharing system - Unstructured PP network (Gnutella, KaZaA, etc.) - Structured PP network (Chord, CAN, Pastry, etc.) - More (Hybrid PP, BitTorrent, etc.)

6 Background History of Peer-to-Peer (PP) systems: - Napster, the first PP content sharing system - Unstructured PP network (Gnutella, KaZaA, etc.) - Structured PP network (Chord, CAN, Pastry, etc.) - More (Hybrid PP, BitTorrent, etc.)

7 Background History of Peer-to-Peer (PP) systems: - Napster, the first PP content sharing system - Unstructured PP network (Gnutella, KaZaA, etc.) - Structured PP network (Chord, CAN, Pastry, etc.) - More (Hybrid PP, BitTorrent, etc.)

8 Background History of Peer-to-Peer (PP) systems: - Napster, the first PP content sharing system - Unstructured PP network (Gnutella, KaZaA, etc.) - Structured PP network (Chord, CAN, Pastry, etc.)? - More (Hybrid PP, BitTorrent, etc.) Pros. Cons.?

9 Background History of Peer-to-Peer (PP) systems: - Napster, the first PP content sharing system - Unstructured PP network (Gnutella, KaZaA, etc.) - Structured PP network (Chord, CAN, Pastry, etc.) - More (Hybrid PP, - Easy BitTorrent, to maintainetc.) Pros. { Cons. { - Finding popular stuff - Fancy local queries - Finding unpopular stuff - No guarantees - Data poisoning and tracking

10 Background History of Peer-to-Peer (PP) systems: - Napster, the first PP content sharing system - Unstructured PP network (Gnutella, KaZaA, etc.) - Structured PP network (Chord, CAN, Pastry, etc.) - More (Hybrid PP, BitTorrent, etc.)

11 Why Chord? Chord s important guarantees: - Decentralized (V.S. Napster) - Scalability: O(log(n)) - Availability (V.S. Gnutella)

12 Lecture Roadmap Background Chord Design Evaluating Chord Comparison

13 Chord In short: A PP lookup service Solves problem of locating a data in a collection of decentralized nodes Supports just one operation: given a key, it maps the key onto a node

14 Initialization: Node

15 Initialization: Node

16 Initialization: Object

17 Initialization: Object

18 Initialization: Table [,) [,) [,)

19 Initialization: Table [,) [,) [,) [,) [,) [,)

20 Initialization: Table [,) [,) [,) [,) [,) [,) [,) [,) [,)

21 Initialization: Table [,) [,) [,) Search an object? [,) [,) [,) [,) [,) [,)

22 Search [,) [,) [,) [,) [,) [,) [,) [,) [,)

23 Search [,) [,) [,) [,) [,) [,) [,) [,) [,)

24 Search [,) [,) [,) [,) [,) [,) [,) [,) [,)

25 Search [,) [,) [,) [,) [,) [,) [,) [,) [,)

26 Search [,) [,) [,) [,) [,) [,) [,) [,) [,)

27 Search [,) [,) [,) [,) [,) [,) [,) [,) [,)

28 Search [,) [,) [,) [,) [,) [,) [,) [,) [,)

29 Search [,) [,) [,) I have! [,) [,) [,) [,) [,) [,)

30 Search [,) [,) [,) I have! [,) [,) [,) [,) [,) [,)

31 If new node joins?

32 Node Joins [,) [,) [,) [,) [,) [,) [,) [,) [,)

33 Node Joins [,) [,) [,) [,) [,) [,) [,) [,) [,)

34 Object Location Changed [,) [,) [,) [,) [,) [,) [,) [,) [,)

35 Table Changed [,) [,) [,) [,) [,) [,) [,) -> [,) -> [,)

36 Table Changed [,) [,) [,) [,) [,) [,) -> [,) [,) [,)

37 Table Changed [,) [,) [,) -> [,) [,) [,) [,) [,) [,)

38 New Table [,) [,) [,) [,) [,) [,) [,) [,) [,) [,) [,) [,)