1 heinz nixdorf institut university of paderborn algorithms und complexity seminar designing...
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HEINZ NIXDORF INSTITUTUniversity of Paderborn
Algorithms und Complexity
SeminarDesigning Peer-to-Peer-Networks
Christian Schindelhauer2004-10-14
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
Motivation
• Peer-to-Peer-Networks– We explore algorithmic problems in Peer-to-Peer networks
• Goal of this seminar: – A small research project which
• extends, • modifies, • simplifies • existing or • new concepts
– in Peer-to-Peer networks• Requirements
– Sufficient knowledge of peer-to-peer networks– E.g. the attendance of the lecture "Algorithmen für
Peer-to-Peer-Netzwerke" of last summer or similar courses– Creativity and the willingness to try out new ideas
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
Goals of the Seminar
• Peer-to-Peer-Networks• Literature research in a hot topic• Develop own ideas• Present new ideas as a research proposal• Interact with others on scientific research• Checkout whether this idea works
– by mathematical analysis and/or– by empirical simulations and/or– by implementation and testing
• Evaluate other workouts• Work alone or with a partner
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
Organization
• See the Web-page
http://wwwcs.upb.de/cs/ag-madh/WWW/Teaching/2004WS/Design-P2P/
• Today: Registration• Topic finding: as soon as possible (Oct. and Nov.)• Weekly meetings:
Every Thursday 2-4pmin F2.211 for topic finding and counseling
• Dec. 6th - 22th, 2004 1st presentation: research proposals• March or May, 2005 Submission of research paper• March or May, 2005 Block seminar with presentation of
research• May 2005 Evaluation, grades and comments
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
The Deliverables
• 1st presentation– Duration 30 min.– Presents
• state of the art• new ideas• research plan
• 2nd presentation– Duration 30 min.– Presents the results of the research
• Research paper– max. 10 pages– shows state of the art– the outcome of the research– Did the proposed idea work? And if, how well? And if not, why
not?
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
How it Counts for the Grade
• 1st presentation– 15%
• Presentation of research– 10 %
• Research paper– 75 %
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
Format and Layout of Research Paper
• American English• max. 10 pages (excluding title page; including pictures, references,
tables etc.)• Accurate and correct citations and references• LATeX, BibTeX• Deliverables
– LATeX source file– BibTeX file– Compiled PDF-output
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
Research Proposals
• Construct the better Peer-to-Peer-Network from scratch• Do something wild and unexpected!• Be creative!• Solve the thing that always annoyed you in your favorite Peer-to-
Peer-Network!• Show that something cannot be better as it is.• Analyze the behavior of some Peer-to-Peer-Network• Simulate the growth and shrinkage of some network• Perform (virtual) attacks on Peer-to-Peer-Networks and analyze
what happens• Make it more secure, robust, efficient, volatile, efficient, softer,
greener, faster, ...• Combine Peer-to-Peer-Networks: Chord & Skipnet, Gnutella &
Pastry, CAN & Koorde
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
And if everything fails ...
• ask me.
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
Research proposal: Routing in Skipnet
• Can we plug in the routing optimization techniques known from CAN, Dhash++ into Skipnet ?
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
Research Proposal: Moving Peers in Chord
• If we do not hash data into Chord, but use a lexicographical ordering
• Can we achieve an efficient balancing by moving peers around?
• How can we efficiently search in this structure?
• How can we find new places for new peers?
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
Research Proposal: Multiple Choice
• O(log n) tests suffice to balance the intervals in a network
• Can we cut down on these tests?
• What happens if we do not use uniform probability distributions?
• What happens if we use distributed algorithms using feedback from the first test?
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
Research Proposal: Symmetric Counting
• Consider the following counting algorithm:
– Choose a random number out of [0,1] for variable xi of peer i
– If two peers communicate (randomly) then they compute the minimum of their variables and store it
– Observe: the expected value of 1/xi converges to n
• How good is this counting algorithm?• How fast does it converge?
• Are there better counting algorithms?
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
To do
• Sign up for the seminar• Help to find an hour for the weekly voluntary meeting• Find your topic and discuss it with me prior to the first presentation• Do some research if you have an idea• Don’t do too much! This is NOT a master thesis! It’s a seminar.
• You may find a partner for common research
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HEINZ NIXDORF INSTITUTEUniversity of Paderborn
Algorithms und ComplexityChristian Schindelhauer
Seminar Designing P2P-Networks
The Schedule
Time Monday TuesdayWednesda
yThursday Friday
7 am - 9 am 4
9 am - 11 am 3 3 0,5 2 1
11am - 1pm Schindelhauer 1 1 1 1
1 pm - 2 pm Schindelhauer
2 pm - 4 pm 0,5 1 Schindelhauer Seminar 1
4 pm - 6 pm 1 Schindelhauer 1 1
6 pm - 8 pm