1 HEINZ NIXDORF INSTITUT University of Paderborn Algorithms und Complexity Seminar Designing Peer-to-Peer- Networks Christian Schindelhauer

2 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian 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

3 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian 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

4 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian Schindelhauer Seminar Designing P2P-Networks Organization See the Web-page Today:Registration Topic finding:as soon as possible (Oct. and Nov.) Weekly meetings: Every Thursday 2-4pm in F2.211 for topic finding and counseling Dec. 6th - 22th, st presentation: research proposals March or May, 2005Submission of research paper March or May, 2005Block seminar with presentation of research May 2005 Evaluation, grades and comments

5 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian 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?

6 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian Schindelhauer Seminar Designing P2P-Networks How it Counts for the Grade 1st presentation –15% Presentation of research –10 % Research paper –75 %

7 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian 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

8 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian 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

9 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian Schindelhauer Seminar Designing P2P-Networks And if everything fails... ask me.

10 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian Schindelhauer Seminar Designing P2P-Networks Research proposal: Routing in Skipnet Can we plug in the routing optimization techniques known from CAN, Dhash++ into Skipnet ?

11 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian 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?

12 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian 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?

13 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian Schindelhauer Seminar Designing P2P-Networks Research Proposal: Symmetric Counting Consider the following counting algorithm: –Choose a random number out of [0,1] for variable x i 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/x i converges to n How good is this counting algorithm? How fast does it converge? Are there better counting algorithms?

14 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian 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

15 HEINZ NIXDORF INSTITUTE University of Paderborn Algorithms und Complexity Christian Schindelhauer Seminar Designing P2P-Networks The Schedule Time MondayTuesdayWednesdayThursdayFriday 7 am - 9 am4 9 am - 11 am330,521 11am - 1pm Schindelhauer pm - 2 pm Schindelhauer 2 pm - 4 pm0,51 Schindelhauer Seminar1 4 pm - 6 pm1 Schindelhauer 11 6 pm - 8 pm

16 HEINZ NIXDORF INSTITUT University of Paderborn Algorithms und Complexity Thanks and let’s go! Verteilte Algorithmen in Netzwerken Christian Schindelhauer