1. HEINZ NIXDORF INSTITUT
University of Paderborn
Algorithms und Complexity
Seminar
Algorithms of the
Internet
Christian
Schindelhauer
2004-04-19
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2. HEINZ NIXDORF INSTITUTE
Motivation University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• The Internet
– is the public global wide-area interconnection network for computers
– grows exponentially
– evolves
The evolution of the Internet
• Crises and catastrophes
– Computer hackers since the 70s
– The traffic breakdown in the 80s
– Denial of service attacks in the 90s
– SPAM forever
• Clever algorithmic solutions
– Secure protocols
– TCP bandwidth control
– DoS-detection
– SPAM-filters
Seminar Algorithms of the Internet 2

3. HEINZ NIXDORF INSTITUTE
Goals of the Seminar University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• Algorithms of the Internet
• Literature recherche in a hot topic
• Write an survey on the state of the art
• Give a presentation on this field
• Interact with others on scientific research
• Provide material for
– the community
– future lectures and seminars
– a book
Seminar Algorithms of the Internet 3

4. HEINZ NIXDORF INSTITUTE
Organization University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• See the Web-page
http://wwwcs.upb.de/cs/ag-madh/WWW/Teaching/2004SS/AlgInternet/
• Today: Registration
Assignment of topics
• Next two meetings: Kickoff and feedback
• May 10th/17th: 2pm-6pm
1st presentation
• From May to July weekly (voluntary) meetings for consultation
• July 19th/26th: 1pm-7pm
2nd presentation
• August 1st (11:59 pm): Deadline for written assignment
• August 30th (2pm): Evaluation, grades and comments
(voluntary participation)
Seminar Algorithms of the Internet 4

5. HEINZ NIXDORF INSTITUTE
The Deliverables University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• 1st presentation
– Duration 15 min.
– Presents
• main issue
• strategy to get the work done
• 2nd presentation
– Duration 45 min.
– Survey of the research area
• Written assignment
– 5-10 pages (pure text without title, references, and figures)
– Survey of the most relevant and interesting work in the assigned
area
Seminar Algorithms of the Internet 5

6. HEINZ NIXDORF INSTITUTE
How it Counts for the Grade University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• 1st presentation
– 0%
• 2nd presentation
– 25 %
• Written assignment
– 75 %
Seminar Algorithms of the Internet 6

7. HEINZ NIXDORF INSTITUTE
The Topics University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
1. The mobile Internet
2. P2P-networks
3. Web caching
4. Algorithms for Web search engines
5. The structure of the Web
6. Security mechanisms of the Internet
7. Denial of service attacks
8. Worms, viruses and spam
9. Epidemic algorithms
10. The Domain Name System (DNS)
11. Bandwidth allocation of TCP
12. Routing algorithms of IP
13. Broadcasting and Multicasting in IP
14. The self-organization of the Internet
15. “Wild card”
Seminar Algorithms of the Internet 7

8. HEINZ NIXDORF INSTITUTE
Contents of Written Assignment University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• Scientific survey on the assigned topic
• For broad audience interested in algorithms and Internet
Table of contents for “Tachyonic Networking”
1. What is Tachyonic Network Transmissions (TNT)
2. Applications of TNT
3. How TNT began
4. The main streams of TNT
5. Recent developments in Tachyonic Networking and Computing
6. Focus: The TachyNet - A clever solution of TNT
7. Open problems and upcoming developments
• References
Seminar Algorithms of the Internet 8

9. Format and Layout of Written HEINZ NIXDORF INSTITUTE
University of Paderborn
Assignment Algorithms und Complexity
Christian Schindelhauer
• American English
• Neutral style
• 5-10 pages (pure text without title, references, and figures)
• Accurate and correct citations and references
• LATeX, BibTeX
• Deliverables
– LATeX source file
– BibTeX file
– Compiled PDF-output
– As many referred text documents as possible
• Electronically if possible
• On paper if necessary
Seminar Algorithms of the Internet 9

10. HEINZ NIXDORF INSTITUTE
1. The Mobile Internet University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• IP Tunneling
• Mobile Ad-hoc Networks
• Handhelds, PDA
• UMTS, WAP
Seminar Algorithms of the Internet 10

11. HEINZ NIXDORF INSTITUTE
2. P2P-Networks University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• 1st generation
– Napster, Kazaa, Gnutella
• Modern P2P-Networks
– CAN, CHORD, Tapestry, …
• Visit the lecture “Algorithmen für Peer-to-Peer-Netzwerke”
• But do not copy (all)
Seminar Algorithms of the Internet 11

12. HEINZ NIXDORF INSTITUTE
3. Web Caching University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• Relieving hot spots in the Internet
• Akamai
• Distributed Hash Tables
• Take a look into the script “Algorithmische Grundlagen des Internets”,
Summer 2003
Seminar Algorithms of the Internet 12

13. HEINZ NIXDORF INSTITUTE
4. Web Search Engines University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• Commercial systems
– Google, Alltheweb, Altavista, etc
– look at websearchengineshowdown.com
• Algorithmic solutions
– PageRank by Brin and Page (Google)
– Kleinberg’s HITS-algorithm
• Take a look into the script “Algorithmische Grundlagen des Internets”,
Summer 2003 and 2004
• Contact Peter Mahlmann!
Seminar Algorithms of the Internet 13

14. HEINZ NIXDORF INSTITUTE
5. The Structure of the Web University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• The WWW is made by individuals
• Yet the structure can be described by Pareto-distribution
– number of links, size of connected components
• The graph structure of the WWW
• Take a look into the script “Algorithmische Grundlagen des Internets”,
Summer 2002
• Link to Web search machines
Seminar Algorithms of the Internet 14

15. 6. Security mechanisms of the HEINZ NIXDORF INSTITUTE
University of Paderborn
Internet Algorithms und Complexity
Christian Schindelhauer
• Are there any?
• Is it all trust-based?
• Start your investigations for the search of the missing crypto-layer of
TCP/IP at the secure shell protocol
Seminar Algorithms of the Internet 15

16. HEINZ NIXDORF INSTITUTE
7. Denial of Service Attacks University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• A new problem from the 90s
• Solutions
– Ingress filtering
– Link testing
– Logging
– ICMP Trace back
– Marking (!!!)
• Take a look into the script “Algorithmische Grundlagen des Internets”,
Summer 2003
Seminar Algorithms of the Internet 16

17. HEINZ NIXDORF INSTITUTE
8. Worms, Viruses, and SPAM University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• Definition
• How they spread
• How they work
• The perfect Antivirus-Software
• An Immune-System for Computers
Seminar Algorithms of the Internet 17

18. HEINZ NIXDORF INSTITUTE
9. Epidemic Algorithms University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• Demers et al.
– Epidemic algorithms for mirroring data bases
– Idea: Spread information like a virus
• Some analyses and new ideas by
– Karp et al. 2001, Randomized Rumor Spreading
• Take a look into the script “Algorithmische Grundlagen des Internets”,
Summer 2002
Seminar Algorithms of the Internet 18

19. HEINZ NIXDORF INSTITUTE
10. The Domain Name System University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• What is it?
• How does it work?
• Why is it so stable?
• Alternatives?
Seminar Algorithms of the Internet 19

20. HEINZ NIXDORF INSTITUTE
11. Bandwidth Allocation of TCP University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• Very classical problem of TCP/IP
• Strangely enough network congestion in the Internet is healed in the
transport layer and not in the network layer
• Start with the scripts
– Algorithmische Grundlagen des Internets”, Summer 2002 and 2003
• Random early deletion (RED)
• New TCP-allocation for Tera-Baud-connections
Seminar Algorithms of the Internet 20

21. HEINZ NIXDORF INSTITUTE
12. Routing Algorithms of IP University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• Start with the standard algorithms
• There are lots of theoretical work of routing algorithms
• Concentrate on such algorithms related to IP
Seminar Algorithms of the Internet 21

22. 13. Broadcasting and Multicasting HEINZ NIXDORF INSTITUTE
University of Paderborn
in IP Algorithms und Complexity
Christian Schindelhauer
• IPv4 and IPv6 foresee multicasting
• How does it work?
• How can it be improved?
• Is it possible to have TV on IP?
Seminar Algorithms of the Internet 22

23. 14. The self-organization of the HEINZ NIXDORF INSTITUTE
University of Paderborn
Internet Algorithms und Complexity
Christian Schindelhauer
• Official organizations of the Internet (IETF, …)
• The Internet and its self-regulation
– socially and technology based
Seminar Algorithms of the Internet 23

24. HEINZ NIXDORF INSTITUTE
15. “Wild Card” University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
• Did we miss something?
• Take a hot topic of your choice within this area.
• If everything fails, I’ll help.
Seminar Algorithms of the Internet 24

25. HEINZ NIXDORF INSTITUT
University of Paderborn
Algorithms und Complexity
Christian Schindelhauer
Thanks and let’s go!
Verteilte Algorithmen in Netzwerken 25