Post on 21-Dec-2015
transcript
EEC-484/584EEC-484/584Computer NetworksComputer Networks
Lecture 1Lecture 1
Wenbing ZhaoWenbing Zhao
wenbing@ieee.org(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)
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Instructor InformationInstructor Information
• Instructor: Dr. Wenbing Zhao– Office: SH434– Email: wenbingz@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!
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What is a Computer Network?What is a Computer Network?
A group of computers inter-connected together
Local Area Network
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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)
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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
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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
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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
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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
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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
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TopicsTopics
• Overview of computer networks– Internet structure– Network edge– Network core– Delay, loss and throughput– Network layers, service models
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TopicsTopics
• Application Layer– HyperText Transfer Protocol (HTTP)– Domain Name Service (DNS)– FTP, Email (will not be covered)
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TopicsTopics
• Transport layer– Main service: End-to-end reliable communication– User Datagram Protocol (UDP)– Transport Control Protocol (TCP)
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TopicsTopics
• Network layer– Main service: routing over multiple hops– Routing algorithms– Internet Protocol (IP)– IP address allocation– Internet Control Protocols: ICMP, ARP, DHCP
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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
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TopicsTopics
• Data Link Layer (part 2): Medium access control protocols– Shared medium, multiple concurrent users,
need to address conflict
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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
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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
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ProjectProject• Build a wiki page
• To gain extra-credit, you are encouraged to build demonstration programs– Java applet or plain Java application
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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)
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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
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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%
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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
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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
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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
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Additional InformationAdditional 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/EEC584-S10/eec584.htm
– Lecture notes will be posted