EEC484584 Computer Networks Lecture 1 Wenbing Zhao wenbingieee

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 Instructor Information • Instructor: Dr. Wenbing Zhao – – Office: SH 434 Email: wenbingz@gmail. com Lecture: MW 6: 00 -7: 50 pm, SH 306 Office hours: MW 2 -4 pm and by appointment Do not use my CSU email to submit your assignment! 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

3 What is a Computer Network? A group of computers inter-connected together Local Area Network 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

4 Internet: “Nuts and Bolts” View PC • Millions of connected server computing devices: hosts = end systems wireless laptop cellular handheld Mobile network Global ISP – Running network apps • Communication links – Fiber, copper, radio, satellite access points – Transmission rate = wired bandwidth links Home network Regional ISP Institutional network • Routers: forward router 12/12/2021 packets (chunks of data) EEC-484/584: Computer Networks 1 -4

5 Internet: “Nuts and Bolts” View • Protocols control sending, receiving of msgs Mobile network Global ISP – e. g. , TCP, IP, HTTP, Skype, Ethernet • Internet: “network of networks” – loosely hierarchical – public Internet versus private intranet Home network Regional ISP Institutional network • Internet standards – RFC: Request for comments – IETF: Internet Engineering Task Force 12/12/2021 EEC-484/584: Computer Networks 1 -5

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 12/12/2021 Network Protocols: • machines rather than humans • all communication activity in Internet governed by protocols define format, order of msgs sent and received among network entities, and actions taken on msg transmission, receipt EEC-484/584: Computer Networks 1 -6

7 What’s a Protocol? A human protocol and a computer network protocol: Hi TCP connection request Hi TCP connection response Got the time? Get http: //www. awl. com/kurose-ross 2: 00 <file> time 12/12/2021 EEC-484/584: Computer Networks 1 -7

8 Achieving Connectivity is Not Easy Transport Service User • Layered approach • We will study issues in each layer in a top-down order transport – Application – Transport – Network – Data Link network Physical Layer is not covered 12/12/2021 application Transport Service Provider EEC-484/584: Computer Networks data link physical Wenbing Zhao

9 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 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

10 Topics • Overview of computer networks – Internet structure – Network edge – Network core – Delay, loss and throughput – Network layers, service models 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

11 Topics • Application Layer – Hyper. Text Transfer Protocol (HTTP) – Domain Name Service (DNS) – FTP, Email (will not be covered) 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

12 Topics • Transport layer – Main service: End-to-end reliable communication – User Datagram Protocol (UDP) – Transport Control Protocol (TCP) 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

13 Topics • Network layer – Main service: routing over multiple hops – Routing algorithms – Internet Protocol (IP) – IP address allocation – Internet Control Protocols: ICMP, ARP, DHCP 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

14 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 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

15 Topics • Data Link Layer (part 2): Medium access control protocols – Shared medium, multiple concurrent users, need to address conflict 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

16 Labs • Purpose: Observe how protocols work • Tools used: Wireshark • 5 lab sessions – – – “Tell me and I forget. Show HTTP me and I remember. Involve DNS me and I understand. ” TCP - Chinese proverb IP Ethernet, ARP & DHCP 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

17 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 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

18 Project • Build a wiki page • To gain extra-credit, you are encouraged to build demonstration programs – Java applet or plain Java application 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

19 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) 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

20 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 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

21 Grading • • Class participation 10% Quizzes 40% Labs 25% Project 25% 12/12/2021 • Grading scale: – – – – A: 90 -100% A-: 85 -89% B+: 80 -84% B: 70 -79% B-: 60 -69% C: 50 -59% F: < 50% EEC-484/584: Computer Networks Wenbing Zhao

22 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 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

23 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/Student. Code. Of. Conduct. pdf 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

24 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 • 4 th Edition (or later), Prentice-Hall 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao

25 Additional Information • Anonymous email: – teachingcsu@gmail. com – Password: – if you are not happy, please do let me know • Course Web site: – http: //academic. csuohio. edu/zhao_w/teaching/EEC 584 -S 10/eec 584. htm – Lecture notes will be posted 12/12/2021 EEC-484/584: Computer Networks Wenbing Zhao