1. EEC-484/584 Computer Networks Lecture 1 Wenbing Zhao wenbing@ieee.org (Part of the slides are based on Drs. Kurose & Ross ’ s slides for their Computer Networking book)

2. 2 6/30/2015EEC-484/584: Computer NetworksWenbing Zhao Instructor Information Instructor: Dr. Wenbing Zhao –Office: SH434 –Email: wenbingz@gmail.comwenbingz@gmail.com –Lecture: MW 6:00-7:50pm, SH306 –Office hours: MW 2-4pm and by appointment Do not use my CSU email to submit your assignment!

3. 3 6/30/2015EEC-484/584: Computer NetworksWenbing Zhao What is a Computer Network? A group of computers inter-connected together Local Area Network

4. 4 EEC-484/584: Computer Networks1-4 Internet: “Nuts and Bolts” View Millions of connected computing devices: hosts = end systems – Running network apps Home network Institutional network Mobile network Global ISP Regional ISP router PC server wireless laptop cellular handheld wired links access points Communication links – Fiber, copper, radio, satellite – Transmission rate = bandwidth Routers: forward packets (chunks of data) 6/30/2015

5. 5 EEC-484/584: Computer Networks1-5 Internet: “Nuts and Bolts” View Protocols control sending, receiving of msgs –e.g., TCP, IP, HTTP, Skype, Ethernet Internet: “network of networks” –loosely hierarchical –public Internet versus private intranet Internet standards –RFC: Request for comments –IETF: Internet Engineering Task Force Home network Institutional network Mobile network Global ISP Regional ISP 6/30/2015

6. 6 EEC-484/584: Computer Networks1-6 What’s a Protocol? Human Protocols: “what’s the time?” “I have a question” introductions … specific msgs sent … specific actions taken when msgs received, or other events Network Protocols: machines rather than humans all communication activity in Internet governed by protocols protocols define format, order of msgs sent and received among network entities, and actions taken on msg transmission, receipt 6/30/2015

7. 7 EEC-484/584: Computer Networks1-7 What’s a Protocol? A human protocol and a computer network protocol: Hi Got the time? 2:00 TCP connection request TCP connection response Get http://www.awl.com/kurose-ross time 6/30/2015

8. 8 EEC-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 –Data Link application transport network data link physical Transport Service Provider Transport Service User Physical Layer is not covered

9. 9 6/30/2015EEC-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

10. 10 6/30/2015EEC-484/584: Computer NetworksWenbing Zhao Topics Overview of computer networks –Internet structure –Network edge –Network core –Delay, loss and throughput –Network layers, service models

11. 11 6/30/2015EEC-484/584: Computer NetworksWenbing Zhao Topics Application Layer –HyperText Transfer Protocol (HTTP) –Domain Name Service (DNS) –FTP, Email (will not be covered)

12. 12 6/30/2015EEC-484/584: Computer NetworksWenbing Zhao Topics Transport layer –Main service: End-to-end reliable communication –User Datagram Protocol (UDP) –Transport Control Protocol (TCP)

13. 13 6/30/2015EEC-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

14. 14 6/30/2015EEC-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

15. 15 6/30/2015EEC-484/584: Computer NetworksWenbing Zhao Topics Data Link Layer (part 2): Medium access control protocols –Shared medium, multiple concurrent users, need to address conflict

16. 16 6/30/2015EEC-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

17. 17 6/30/2015EEC-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 –All answers must have supporting snapshots

18. 18 6/30/2015EEC-484/584: Computer NetworksWenbing Zhao Project Build a wiki page To gain extra-credit, you are encouraged to build demonstration programs –Java applet or plain Java application

19. 19 6/30/2015EEC-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)

20. 20 6/30/2015EEC-484/584: Computer NetworksWenbing Zhao Quizzes 4 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

21. 21 6/30/2015EEC-484/584: Computer NetworksWenbing Zhao Grading Class participation 10% Quizzes 40% Labs 25% Project 25% Grading scale: –A: 90-100% –A-: 85-89% –B+: 80-84% –B: 70-79% –B-: 60-69% –C: 50-59% –F: < 50%

22. 22 6/30/2015EEC-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

23. 23 6/30/2015EEC-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/StudentCodeOfConduct.pdfhttp://www.csuohio.edu/studentlife/StudentCodeOfConduct.pdf

24. 24 6/30/2015EEC-484/584: Computer NetworksWenbing Zhao Reference Texts James F. Kurose, Keith W. Ross, –Computer Networking: A Top-Down Approach Featuring the Internet 5 th Edition, Addison-Wesley Andrew S. Tanenbaum : –Computer Networks 4th Edition (or later), Prentice-Hall

25. 25 6/30/2015EEC-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-S10/eec584.htmhttp://academic.csuohio.edu/zhao_w/teaching/EEC584-S10/eec584.htm –Lecture notes will be posted