Your SlideShare is downloading. ×
0
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Simulator
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Simulator

153

Published on

Published in: Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
153
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
1
Comments
0
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  • 1. The Query-Cycle Simulator for Simulating P2P Networks Mario T. Schlosser Tyson E. Condie Sepandar D. Kamvar Stanford University
  • 2. <ul><li>Problem: </li></ul><ul><ul><li>Accurately Simulate Real-World P2P Networks. </li></ul></ul><ul><li>Motivation: </li></ul><ul><ul><li>Testing P2P Algorithms. </li></ul></ul>Problem For each peer i { -Repeat until convergence { - Compute . . . - Send . . . } }
  • 3. Goals <ul><li>P2P Simulator </li></ul><ul><ul><li>Descriptive </li></ul></ul><ul><ul><li>Simple </li></ul></ul><ul><ul><li>Easily Extensible </li></ul></ul><ul><ul><li>Make it available on the web so that people can test and compare their algorithms on a standard platform. </li></ul></ul>
  • 4. Query Cycle Model Query Cycle 1
  • 5. Query Cycle Model Query Cycle 2
  • 6. Query Cycle Model Query Cycle 3
  • 7. Properties to Model <ul><li>Peer Content </li></ul><ul><li>Network Parameters </li></ul><ul><li>Peer Behavior </li></ul>
  • 8. Properties to Model <ul><li>Peer Content </li></ul><ul><ul><li>How Much? </li></ul></ul><ul><ul><li>What Type? </li></ul></ul><ul><li>Network Parameters </li></ul><ul><li>Peer Behavior </li></ul>
  • 9. Data Volume <ul><li>Observations </li></ul><ul><li>Model </li></ul>Simulator assigns # of files owned by peer i according to distribution. Saroiu,Gummandi,and Gribble. A Measurement Study of Peer-to-Peer File Sharing Systems, 2002.
  • 10. Content Type: Observations <ul><li>Content Categories </li></ul><ul><li>Zipf distribution on file popularity </li></ul>Crespo and Garcia-Molina. Semantic Overlay Networks, 2002. Korfhage, Information Storage and Retrieval, 1997. Punk Rock Hip-Hop Jazz
  • 11. Content Type: Model <ul><li>Modeling Content Categories: </li></ul><ul><ul><li>Assume n content categories. C={c 1 ,c 2 ,…,c n } </li></ul></ul><ul><ul><li>A peer i is assigned content categories according to the Zipf distribution: </li></ul></ul><ul><ul><li>It is then assigned an interest level p(c|i) to each of the assigned content categories by a uniform random distribution. </li></ul></ul>
  • 12. Content Type: Model <ul><li>Modeling Files: </li></ul><ul><ul><li>Each distinct file f may be uniquely identified by {c,r} </li></ul></ul><ul><ul><li>A peer is assigned files by: </li></ul></ul>
  • 13. Recap on Content Assignment
  • 14. Recap on Content Assignment Assign Data Volume
  • 15. Recap on Content Assignment {c1, c3, c4} Assign Content Categories
  • 16. Recap on Content Assignment {c1=.5, c3=.3, c4=.2} Assign Interest Level to Content Categories
  • 17. Recap on Content Assignment {c1=.5, c3=.3, c4=.2} Assign Files {c,r}={c1,f1} {c,r}={c1,f7} . . .
  • 18. Properties to Model <ul><li>Peer Content </li></ul><ul><li>Network Parameters </li></ul><ul><ul><li>Topology </li></ul></ul><ul><ul><li>Bandwidth </li></ul></ul><ul><li>Peer Behavior </li></ul>
  • 19. Network Parameters <ul><li>Topology: </li></ul><ul><ul><li>Observation: Power Law Topology </li></ul></ul><ul><ul><li>Model: probability of connecting to a peer is proportional to the degree of that peer. </li></ul></ul><ul><li>Bandwidth </li></ul><ul><ul><li>Simple Bandwidth Model </li></ul></ul><ul><ul><li>Can be easily extended. </li></ul></ul>
  • 20. Properties to Model <ul><li>Peer Content </li></ul><ul><li>Network Parameters </li></ul><ul><li>Peer Behavior </li></ul>
  • 21. Query-Cycle Model <ul><li>At each cycle, peer i may be: </li></ul><ul><ul><li>active </li></ul></ul><ul><ul><li>inactive </li></ul></ul><ul><ul><li>or down </li></ul></ul>
  • 22. <ul><li>At each cycle, peer i may be: </li></ul><ul><ul><li>active </li></ul></ul><ul><ul><li>inactive </li></ul></ul><ul><ul><li>or down </li></ul></ul>Query-Cycle Model <ul><li>Issues a single query. </li></ul><ul><li>Waits for incoming responses. </li></ul><ul><li>Selects a source and downloads file. </li></ul><ul><li>Also: </li></ul><ul><ul><li>Responds to queries. </li></ul></ul><ul><ul><li>Forwards query messages. </li></ul></ul>
  • 23. <ul><li>At each cycle, peer i may be: </li></ul><ul><ul><li>active </li></ul></ul><ul><ul><li>inactive </li></ul></ul><ul><ul><li>or down </li></ul></ul>Query-Cycle Model <ul><li>Responds to queries. </li></ul><ul><li>Forwards Query Messages. </li></ul>
  • 24. <ul><li>At each cycle, peer i may be: </li></ul><ul><ul><li>active </li></ul></ul><ul><ul><li>inactive </li></ul></ul><ul><ul><li>or down </li></ul></ul>Query-Cycle Model <ul><li>Does nothing. </li></ul>
  • 25. Properties to Model <ul><li>Peer Content </li></ul><ul><li>Network Parameters </li></ul><ul><li>Peer Behavior </li></ul><ul><ul><li>Uptime and Session Duration </li></ul></ul><ul><ul><li>Query Activity </li></ul></ul><ul><ul><li>Queries </li></ul></ul><ul><ul><li>Query Responses </li></ul></ul><ul><ul><li>Downloads </li></ul></ul>
  • 26. Uptime <ul><li>Observations </li></ul><ul><li>Model </li></ul>At each query cycle, probability of being up is drawn from distribution in Saroiu et al. Saroiu,Gummandi,and Gribble. A Measurement Study of Peer-to-Peer File Sharing Systems, 2002.
  • 27. Queries <ul><li>Observations </li></ul><ul><ul><li>None </li></ul></ul><ul><li>Model </li></ul><ul><ul><li>Based on the idea that peers query for files in the same categories that they own. </li></ul></ul>
  • 28. Responses and Downloads <ul><li>Responses </li></ul><ul><ul><li>If a peer receives a query for which it owns the file, it responds. </li></ul></ul><ul><li>Source Selection </li></ul><ul><ul><li>Random </li></ul></ul>
  • 29. Extensions <ul><li>Different Types of Peers </li></ul><ul><ul><li>i.e., Malicious Peers </li></ul></ul><ul><li>Different Models for Different Situations </li></ul><ul><ul><li>Reputation-based source selection. </li></ul></ul><ul><ul><li>Edutella: model distribution over markups rather than content categories. </li></ul></ul><ul><ul><li>Web Services: Change models for content distribution, query activity, etc. However, parameters are the same. </li></ul></ul>
  • 30. Samples
  • 31. Future Work <ul><li>Test predictions against observations in P2P networks “in the wild”. </li></ul><ul><li>Observations, observations, observations. </li></ul><ul><li>Model other networks. </li></ul>
  • 32. The End <ul><li>Code, demos will be available at http://www.stanford.edu/~sdkamvar/research.html next monday. </li></ul>
  • 33. Motivation Network or peer property Affected algorithms <ul><li>Topology </li></ul><ul><li>Content distribution </li></ul><ul><li>Bandwidth, uptime of peers </li></ul><ul><li>Structuring algorithms </li></ul><ul><li>Whatever </li></ul><ul><li>Stability of trust algorithms </li></ul>
  • 34. Query Activity <ul><li>Observations </li></ul><ul><li>Model </li></ul>At each query cycle, . . . Saroiu,Gummandi,and Gribble. A Measurement Study of Peer-to-Peer File Sharing Systems, 2002.

×