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EE:450 – Computer Networks
Discussion Session Fall 2021
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Teaching Assistant 1
▪ Name: Mr.
• E-Mail Address:
• Office: PHE320, (213) 821-4648 (Pending approval
from department for in-person office hours),
otherwise a zoom link will be created shortly
• Office Hours: Monday 10am-12pm
• Zoom Link:
https://us02web.zoom.us/j/5680503313?pwd=UVE2
Q0x2ZlRIMGJkMmJtTW5laUNCZz09
• Meeting ID: 568 050 3313
• Passcode: HOLA
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Teaching Assistant 2
▪ Name: Mr. Yongqin Wang
• E-Mail Address:
• Office: PHE320, (213) 821-4648 (Pending approval
from department for in-person office hours),
otherwise a zoom link will be created shortly
• Office Hours: Friday, 3pm-5pm
• Zoom Link:
https://usc.zoom.us/j/4477365616?pwd=WFgvU0VyK
1RlRDFhOHQvdTRueWVFdz09
• Meeting ID: 447 736 5616
• Passcode: A1F5Kp
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Teaching Assistant 3
▪ Name: Mr.
• E-Mail Address:
• Office: PHE320, (213) 821-4648 (Pending approval
from department for in-person office hours),
otherwise a zoom link will be created shortly
• Office Hours: Wednesday, 10am-12pm
• Zoom Link:
https://usc.zoom.us/j/99850899432?pwd=T1RQWDd
LT01ZOVB6WXhQc2pPSE44UT09
• Meeting ID: 998 5089 9432
• Passcode: 399742
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My Responsibilities
■ Conducting a weekly discussion
■ Maintaining the course web site
■ Conducting office hours (open to all students)
■ Designing and grading projects
■ Assisting (via e-mail)
Regardless of your enrollment in the discussion session and Regardless on which discussion session you attend your email should be forwarded to your designated TA (TBD)
■
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TA Assignments (TBD)
■ Student will be divided between the TAs
■ The designated TA will be responsible for
answering the emailed questions from his
assigned students
■ The student can only email his designated TA if he
has any questions
■ Emails sent to different TA will be forwarded to
the student designated TA
■ However, we strongly recommend that you use
Piazza class discussion board for your questions. This way it will benefit everyone.
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Board
■ ■ ■ ■ ■ ■ ■
■ You should have received an email to join USC 450 discussion board in Piazza website.
■ We encourage you to use it for posting questions regarding to Homeworks/Labs/Project.
■ Also, if necessary, you can post anonymously.
■ The TAs will answer your questions, so people visit this website often and make sure to check if your question was asked before to avoid double posts.
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Course webpages
■ Class Website (you must visit the class website frequently):
■ http://den.usc.edu
■ Webcasts for both lecture and discussion are available (all sessions)
■ Lecture and discussion notes, assignments, solutions, labs and
project as well as important class announcements/news will be
posted on the website
■ Whenever a document is posted on the website, you will be notified
by email with EE450 in the subject line
■ DO CHECK and READ your emails every day!
■ TAs may make mistakes – We appreciate your constructive feedback
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Homeworks
■ 5 – 6 homeworks this Semester
■ You must submit HWs and Labs to the online submission folder by
■ HW/Lab must NOT be emailed to TA or the professor
the due date
■ Goal of Homework
■ To help you learn the Material
■ For you to gain experience in solving networking-related problems
■ Homework is difficult
■ Help is available – but not at last minute
■ Start Early – Cannot answer 20 emails an hour before homework is
due
■ Come to discussion/office hours with Questions
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Extra Credit Labs
■ Extra credit Labs (Strongly recommended)
■ Protocol analysis using Wireshark (Ethereal) ■ 2 labs, assigned before the Midterm
■ Network simulation using Mininet
■ 3 labs, assigned after the midterm
■ Mininet is a network emulator that creates a realistic virtual network on a
single virtual machine
■ Each lab is worth 4 points added to your midterm grade out of 100 i.e. you can potentially earn 20 points of extra credit if you
Successfully fulfill all 5 labs
Introduction to Wireshark (Ethereal) and Instructions for Downloading and Installing Mininet will be posted on DEN>Course
documents in the corresponding folders
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Hard Deadline Policy Regarding Collecting Graded Assignments and Grade Adjustments
■ Once grades for an assignment are ready for viewing on DEN, TAs will notify the class by email and announce a deadline as the last day to resolve grading issues
■ Please note that NO grade adjustments are allowed or accepted after the deadline for a specific assignment. This applies to students in both sessions as well as DEN remote students
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How and When to Resolve
■ Students have about 2 weeks from the time of the notification email to:
■ Contact the designated grader (and if necessary the designated TA) to resolve any grading issues and have their grade updated in the grade book.
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Project
■ Client/server socket programming
■ Mandatory (hard deadline strictly enforced)
■ Important to learn (a stepping stone to CS-551)
■ Will expose you to the basics network programming
■ Requirements
■ Knowledge of C or C++ programming (Medium to Skillful)
■ Knowledge of Unix (Basic)
■ Knowledge of Network Programming (Network Sockets)
■
If you are new to socket programming, do study this tutorial
carefully asap and before starting the project) at http://beej.us/guide/bgnet
■ TAs will guide and help you only with the project itself
■ They will NOT teach you C/C++ programming, debugging, Unix or
network programming
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Project Platform
■ ■
■ ■
■ ■
■
We will create an Ubuntu virtual machine (VM) and share it with everyone.
● ●
Oracle VirtualBox (Recommended)
You should load that VM in your laptops using VM applications such as:
VMware etc.
During grading, TAs will load a fresh copy of the VM and grade your projects on it.
You may write your code in a Linux editor on the VM (preferred method) or in any other editor elsewhere and copy it to VM later for testing.
No MS-Windows programs will be accepted.
Ubuntu VM copy will provided when the project is released.
In the meantime, we recommend that you get yourself familiar with C/C++ and Linux.
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Discussion Class
■ Discussion is not a Lecture Class
■ In order to be useful I need your help
■ Please come ready with Questions
■ Do the homework before hand
■ Start early! HW can not be done in just a few
hours
■ I want you to be able to point out the tricks or
subtleties to some of the problems in
networking
■ The more exposure you have to the subject,
the more prepared you will be for the exams
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Format
■ I’ll typically give a short lecture on some of the key topics for the week
■ Go over some extra examples
■ Go over any questions
■ Let me know:
■ If something is not clear
■ If you can’t read my handwriting
■ I’m speaking too fast
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Getting Help
■ Methods
■ Ask Me in Class
■ Come to office hours
■ Send me an email (Check your Designated
TA)
■ Notice: If you are on campus, It’s more effective to come and get help
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Other Ideas
■ Use the web for help
■ Be careful
■ Searches on Google usually return some very good info
■ You may talk with each other about concepts
discussed in class, but remember:
■ All assignments (HW, Labs and Project) require
individual effort!
■ Don’t copy! It doesn’t pay off and it is NOT
allowed!!!
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Why Networks?
■ Networks are connections
■ Computers are powerful by themselves
but many times more powerful when they are connected
■ We live in a world where having information is not worth much, but being able to share it is very valuable
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Some Networking Basics
■ Lets Define a Communication System
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Three goals
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Simplex
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Half-Duplex
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Local Area Network
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Metropolitan Area Network
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Wide Area Network
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Internetwork (Internet)
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Some Networking Basics
■ Lets Define a Communication System
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Basics continued…
■ Communicating parties can be ■ Telephones
■ Cell Phones
■ TV/Radio transmitters/receivers ■ Computers
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Basics continued…
■ Transmission medium can be ■ Twisted pair copper wire
■ Coaxial cable
■ Optical fiber
■ Or simply air…
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Transmission
■ Transmitter
■ Messages are converted into electrical signals
■ Transmission Medium
■ Transmitter End: Electrical signals are converted into
suitable transmission signals depending on the transmission
medium. (EM waves for air, Light for optical fiber, etc)
■ Transmission signals are propagated through the medium
■ Receiver End: Converts the transmission signals into
Electrical signals
■ Receiver
■ Electrical signals are decoded to get the original message
back.
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SIGNALS
■ The electrical signals can be ANALOG or DIGITAL
■ ANALOG – the amplitude can take infinite number of values
■ Ex: TV/Radio transmission
■ DIGITAL – the amplitude can take finite
number of values only
■ Ex: Computer Communications (uses two logic
values 0 and 1)
We will be dealing with DIGITAL transmissions
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