1. EEC-484/584 Computer Networks Lecture 1 Wenbing Zhao Cleveland State University wenbing@ieee.org

2. 2 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Instructor Information Instructor: Dr. Wenbing Zhao –Office: SH434 –Email: wenbing@ieee.orgwenbing@ieee.org –Lecture: MW 6:00-7:50pm, SH306 –Office hours: MW 2:00-4:00pm and by appointment

3. 3 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao What is Computer Network? A group of computers inter-connected together Local Area Network

4. 4 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao What is Computer Network? A group of computer inter-connected together Wide Area Network

5. 5 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao What are the Elements in a Computer Network? Hosts – computers Communication medium – cables, wireless medium (EM waves) Routers – forward a packet from one place to another, decide on a path from source to destination Protocols – rules governing the communication

6. 6 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Achieving Connectivity is Not Easy Layered approach We will study issues in each layer in a top-down order –Application –Transport –Network –Link application transport network link physical Transport Service Provider Transport Service User Physical Layer is not covered

7. 7 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Course Objectives Good understanding of the computer networking technologies –How connectivity is achieved? Hands on experience –Labs: observe how protocols work –Project: write about computer networks elements and hopefully write some demo programs

8. 8 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Prerequisite Officially: graduate standing Ideally: You should have sufficient computer engineering background –You have taken undergraduate-level operating systems, data structure and algorithms, and programming language courses –You know how to write technical reports in English (in your own words)

9. 9 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Topics Overview of computer networks –Types of computer networks –Reference models –Protocols, services and interfaces –Circuit switched vs. packet switched –Connection oriented vs. connectionless

10. 10 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Topics Application Layer –HyperText Transfer Protocol (HTTP) –Domain Name Service (DNS) –FTP, Email Physical Layer: skipped

11. 11 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Topics Transport layer –Main service: End-to-end reliable communication –User Datagram Protocol (UDP) –Transport Control Protocol (TCP)

12. 12 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Topics Network layer –Main service: routing over multiple hops –Routing algorithms –Internet Protocol (IP) –IP address allocation –Internet Control Protocols: ICMP, ARP, DHCP

13. 13 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Topics Data Link Layer (part 1): Basic communication protocols –Main service: provide point-to-point single hop communication service to higher layer –Framing: group bits together –Error control –Flow control

14. 14 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Topics Data Link Layer (part 2): Medium access control protocols –Shared medium, multiple concurrent users, need to address conflict

15. 15 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Labs Purpose: Observe how protocols work Tools used: Wireshark 5 lab sessions –HTTP –DNS –TCP –IP –Ethernet, ARP & DHCP “Tell me and I forget. Show me and I remember. Involve me and I understand.” - Chinese proverb Lab instructions taken from Kurose’s book

16. 16 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Labs Lab sessions are mandatory unless an exception is granted in advance I will not accept the lab report if you do now show up during the lab session without prior notice Lab report must be typed (with both questions and answers) and submitted in hardcopy on or before due date

17. 17 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Special Labs Learning networking protocols with iPod Touch – Sponsored by the CSU Center for Teaching Excellence Up to three labs –Reliable data communication –Routing –Medium access protocols

18. 18 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Projects Build a wiki page For individual or a team of two To gain extra-credit, you are encouraged to build demonstration programs –Java applet or plain Java application, –NS2 simulator

19. 19 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Project Select a topic related to Computer Networks and build a wiki page for the topic on http://www.pbwiki.com/ or a similar Web hosting site http://www.pbwiki.com/ –For example topics, see the syllabus Furthermore, peer-review and revision steps are required –Each team is required to review three wiki pages built by other teams anonymously –You must revise your page according to the reviews

20. 20 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Class Participation 10% of the course credit In general, there is a mock quiz in the beginning of each lecture, so that –I know who is here & I get feedback for my teaching To obtain the full credit for class participation, you must satisfy ALL of the following conditions: –You do not miss more than 2 lectures –You do not miss any quiz and lab sessions –You asked at least 10 questions during the semester You will lose all 10% credit if you miss more than 6 lectures/labs (unless an exception is granted)

21. 21 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Class Participation Send me an email with the following information for each question you have asked within 24 hours after each lecture: –The question you asked –My response –Your comment on my response and suggestion for improvement, if any

22. 22 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Class Participation You are also encouraged to send me comments/suggestions on how you would like me to improve my teaching so that it is more conducive For each piece of comment/suggestion, it will be counted as 2 questions If you max out the class participation credit, you will get extra credit if you provide further feedbacks

23. 23 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Quizzes 5 quizzes. Basically one quiz for each layer The quizzes are closed book and closed notes, except that you are allowed to bring with you a one-page hand-written cheat sheet no larger than the US letter size (double-sided allowed) No makeup quizzes! No midterms and final exam Perks: only the best of 4 quizzes will be counted towards your gradePerks: only the best of 4 quizzes will be counted towards your grade

24. 24 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Grading Class participation 10% Quizzes 50% Labs 20% Project 20% Grading scale: –A: 90-100% –A-: 85-89% –B+: 75-84% –B: 65-74% –B-: 60-64% –C: 50-59% –F: < 50%

25. 25 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Do not cheat! Do not copy other student ’ s lab report, quizzes or projects Do not copy someone else ’ s work found on the Internet –You can quote a sentence or two, but put those in quote and give reference

26. 26 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Consequences for Cheating You get 0 credit for the task you have cheated If the task is worth more than 25% of the course, it is considered a major infraction Otherwise, it is considered a minor infraction For major infraction and repeated minor infractions –You will get an F grade, and –You may be suspended or repulsed from CSU CSU Code of Conduct –http://www.csuohio.edu/studentlife/StudentCodeOfCondu ct.pdfhttp://www.csuohio.edu/studentlife/StudentCodeOfCondu ct.pdf

27. 27 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Reference Texts Andrew S. Tanenbaum : –Computer Networks 4th Edition (or later), Prentice-Hall, 2003 James F. Kurose, Keith W. Ross, –Computer Networking: A Top-Down Approach Featuring the Internet 3 rd Edition (or later), Addison-Wesley, 2004

28. 28 Spring 2009EEC-484/584: Computer NetworksWenbing Zhao Additional Information Anonymous email: –teachingcsu@gmail.comteachingcsu@gmail.com –Password: –if you are not happy, please do let me know Course Web site: –http://academic.csuohio.edu/zhao_w/teaching/EEC584 -S09/eec584.htmhttp://academic.csuohio.edu/zhao_w/teaching/EEC584 -S09/eec584.htm –Lecture notes will be posted