EEC-484/584 Computer Networks Lecture 1 Wenbing Zhao [email protected] (Part of the slides are based...

EEC-484/584EEC-484/584Computer NetworksComputer Networks

Lecture 1Lecture 1

Wenbing ZhaoWenbing Zhao

[email protected](Part of the slides are based on Drs. Kurose & (Part of the slides are based on Drs. Kurose &

RossRoss’’s slides for their s slides for their Computer Networking Computer Networking book)book)

22

04/18/2304/18/23 EEC-484/584: Computer NetworksEEC-484/584: Computer Networks Wenbing ZhaoWenbing Zhao

Instructor InformationInstructor Information

• Instructor: Dr. Wenbing Zhao– Office: SH434– Email: [email protected] – 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!

33


What is a Computer Network?What is a Computer Network?

A group of computers inter-connected together

Local Area Network

44

EEC-484/584: Computer NetworksEEC-484/584: Computer Networks 1-1-44

Internet: “Nuts and Bolts” ViewInternet: “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

wirelesslaptop

cellular handheld

wiredlinks

access points

• Communication links– Fiber, copper, radio,

satellite– Transmission rate =

bandwidth

• Routers: forward packets (chunks of data)

04/18/2304/18/23

55


Internet: “Nuts and Bolts” ViewInternet: “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

04/18/2304/18/23

66


What’s a Protocol?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

04/18/2304/18/23

77


What’s a Protocol?What’s a Protocol?A human protocol and a computer network protocol:

Hi

Hi

Got thetime?2:00

TCP connection request

TCP connectionresponseGet http://www.awl.com/kurose-ross

<file>

time

04/18/2304/18/23

88


Achieving Connectivity is Not EasyAchieving 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

99


Course ObjectivesCourse 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

1010


TopicsTopics

• Overview of computer networks– Internet structure– Network edge– Network core– Delay, loss and throughput– Network layers, service models

1111


TopicsTopics

• Application Layer– HyperText Transfer Protocol (HTTP)– Domain Name Service (DNS)– FTP, Email (will not be covered)

1212


TopicsTopics

• Transport layer– Main service: End-to-end reliable communication– User Datagram Protocol (UDP)– Transport Control Protocol (TCP)

1313


TopicsTopics

• Network layer– Main service: routing over multiple hops– Routing algorithms– Internet Protocol (IP)– IP address allocation– Internet Control Protocols: ICMP, ARP, DHCP

1414


TopicsTopics

• 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

1515


TopicsTopics

• Data Link Layer (part 2): Medium access control protocols– Shared medium, multiple concurrent users,

need to address conflict

1616


LabsLabs

• 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

1717


LabsLabs

• 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

1818


ProjectProject• Build a wiki page

• To gain extra-credit, you are encouraged to build demonstration programs– Java applet or plain Java application

1919


Class ParticipationClass 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)

2020


QuizzesQuizzes• 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

2121


GradingGrading• 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%

2222


Do not cheat!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

2323


Consequences for CheatingConsequences 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.pdf

2424


Reference TextsReference Texts

• James F. Kurose, Keith W. Ross,– Computer Networking: A Top-Down

Approach Featuring the Internet• 5th Edition, Addison-Wesley

• Andrew S. Tanenbaum : – Computer Networks

• 4th Edition (or later), Prentice-Hall

2525


Additional InformationAdditional Information

• Anonymous email:– [email protected]– Password:

– if you are not happy, please do let me know

• Course Web site:– http://academic.csuohio.edu/zhao_w/teaching/EEC584-S10/eec584.htm

– Lecture notes will be posted

EEC-484/584 Computer Networks Lecture 1 Wenbing Zhao [email protected] (Part of the slides are based...

Documents

Transcript of EEC-484/584 Computer Networks Lecture 1 Wenbing Zhao [email protected] (Part of the slides are based...