Lecture 1

1. Lecture 1 Advance Topics in Networking

2. Lecture 1: Introduction • Course Goals • Course Topics • Student Introduction • Research Paper Review • Hints on Reading a Paper • Reviewers Guidelines • Paper Review Guidelines • First Papers: For this week

3. Course Goals • Critical examination of current topics in networking • What assumptions are no longer valid • What are new research problems to look at • Understanding solutions in context • Goals • Assumptions • Learn how to do research • Paper review, writing and presentation • Appreciate what is good research • Problem selection • Solution and Research Methodology • Presentation • Apply what you learn in this class

4. Course Topics • Intranet / internet routing • Traffic engineering • Network diagnosis and rectification • Network Host Security • Network Anomaly Detection • Network Traffic Classification • Peer to Peer Networks • Privacy and anonymity • Network measurement • Future directions in Internet architecture • Cellular Networks • Ad hoc and Infrastructure Networks

5. Student Introduction • Please introduce yourself • Name, research area, … • Say a few words about what you like to learn about networking • Email me if there is any other specific topic not already included in the topics slide to be covered in this class • What you think are “un-solved” problems in computer networks • What kind of help is required for writing your own research papers • How many students can group together for presentations, projects and research groups • How can we help in your research

6. Research Paper Review • Read at least one or two papers on the subject for writing good reviews. • Read some of the associated literature (by following some of the citations provided in the paper). • You are free to pick a review format, but a common format is as follows. • First, summarize what you understood of the paper in 1-2 paragraphs. • Then, point out what you liked about the paper. • After that, discuss the main flaws (if any) that you found in the paper. • Follow it with detailed suggestions for improving the paper (e.g. suggest experiments, other approaches to consider, better ways to present data etc.).

7. Hints on Reading a Paper • Three stage approach • Read quickly in 5-10minutes • Read with greater care; ignore proofs • Deconstruct paper; question all assumptions

8. Stage 1: 5-10 minute read • Read title, abstract, introduction, section headings, conclusion, reference list. • Look for “5 C’s” • Category: What type of paper is it? • Context: Where does it fit in? • Correctness: Do assumptions make sense? • Contributions: What are the main ones? • Clarity: Is it well-written?

9. Stage 2: Read with Care • Spend about an hour re/reading paper in detail • Try to understand the “story” • Summarize the main concepts • Identify main supporting evidence

10. Stage 3: Deconstruct the paper • This can take one or more hours • Understand every proof • Question every assumption • Identify missing references • Why was the paper written this way? • How else could the paper have been written?

11. Reviewers Guidelines • Paper reviews should be submitted at the beginning of every class in hardcopies. • If you cannot attend the class, please email your review to adeel@uettaxila.edu.pk • Cell: 0334-5488-733 • Proxy: web.uettaxila.edu.pk • Port: 8765 • Login: guest1 Pass: guest1 • http://web.uettaxila.edu.pk/cms/msATNau09/

12. Paper Review Guidelines • Paper Summary (3-5 sentences) • What are the major problem(s) or issue(s) addressed by the paper? • Are they important and/or interesting? • Why?* • What are the main results of this paper? • Are they useful or significant? • Will anyone benefit from it? • Will it be used by others in their research? • Does it open up new areas or resolve an important open issue?

13. Paper Review Guidelines • What is the approach/methodology in this paper? • Comment on its degree of novelty, creativity, and technical depth. • How would you use them for other studies? • Strength: What are the major strengths of the paper? • Weaknesses: What are the major flaws of the paper? • The flaws can be any simplications made that may significantly affect the results.

14. Paper Review Guidelines • Assumptions: What are the inherent assumptions or the models used in the paper (if any)? Are they still valid today? • Future work: What are the avenues for future work or follow-up studies? • If you are asked to work on the same problem today, how would you do differently? • Detailed Comments: Please provide detailed comments that will be helpful for further assessing the paper.

15. First papers: For this week Read deep • The Design Philosophy of the DARPA Internet Protocols - Clark, 1988 • End-to-End Arguments in System Design - Saltzer, Reed and Clark, 1984 The green highlighted paper above is to be reviewed by the students as home assignment 1

16. The Design Philosophy of the DARPA Internet Protocols Goal 0: An “effective” technique for multiplexed utilization of existing interconnected networks. Goal 1: Internet communication must continue despite loss of networks or gateways. Goal 2: The Internet must support multiple types of communication service. Goal 3: The Internet architecture must accommodate a variety of networks [underneath]. Goal 4: The Internet architecture must permit distributed management of its resources. Goal 5: The Internet architecture must be cost effective. Goal 6: The Internet architecture must permit host attachment with a low level of effort. Goal 7: The resources used in the internet architecture must be accountable.

17. Goal 0: An effective technique for multiplexed utilization of existing interconnected networks • Leads to: Different networks connected together by packet switched, store-and-forward routers/gateways • Why interconnect existing networks and not design a new overall network from scratch? • Why was packet switching picked for multiplexing? What were the choices?

18. Goal 1: Internet communication must continue despite loss of networks or gateways. “Entities should be able to continue communicating without having to reestablish or reset the high level state of their conversation” “The architecture [should] mask competely any transient failure” Leads to: • “Fate-sharing” model - only lose communication state if the end-host is lost. • Stateless packets switches => datagrams • What alternative design could there be? • How does the Internet do this? • To what extent does it accomplish it? • To what extent is it possible? • Could a “dedicated” new network be more reliable?

19. Other goals Goal 4: The Internet architecture must permit distributed management of its resources • To what extent does it accomplish this? Goal 5: The Internet architecture must be cost effective. • Is it? Goal 7: The resources… must be accountable • What dos this mean? • What would such a network look like?

20. Minimum Assumptions of interconnected networks • Can transport a datagram • …of reasonable size • …with reasonable chance of delivery Interesting comments: • Reliability and qualities of service were not built in because they would require too much change. • Datagram as a building block, not as a service.

21. Other discussion questions • Originally TCP+IP were joined, but were later split. Why was that? • “It proved more difficult than first hoped to provide multiple types of service without explicit support from the underlying network” • Why is that? What has happened since?

22. Other discussion questions • Interesting comment: “The most important change in the Internet…will probably be the development of a new generation of tools for management of resources...” • Why has distributed management been so hard?

23. Other discussion questions • Claim: Correctness of a protocol can be automated, whereas performance is harder to understand and often dictated by the operating system. • At the time, simulation was hard/poor. • Analytical tools lacking.

24. Author’s conclusion • “Datagram” good for most important goals, but poor for the rest of the goals. • Processing packets in isolation, resource management, accountability all hard. • Proposes flows and soft-state for the future.

25. The End Questions?