CS422: Computer Networks (Spring 2021)

Instructor: Chunyi Peng

She is hiring: Independent study on mobile networks is open. More please refer to her homepage and MI-LAB>.

CS422 is an undergraduate-level course about Computer Networks at the Deptarment of Computer Science at Purdue University. In this course, we will use Internet, one of the largest and critical cyber infrastcture, as the showcase of computer networks to learn how to build Internet which is used by almost everyone everyday. We will go through main network protocols used by Internet (called TCP/IP stack) and use them to understand networking principles and practice. Students will advance from daily users to potential developers, understanding why we built Internet this way and how to innovate next-generation Internet.

What's New

Due to COVID-19, CS422 is ONLINE (via ZOOM) that supports two synchronous and asynchronous sections.

The lecture will be recorded in the synchronous section and then uploded to course resources for aynchronous and distant learning. As you all know, the essential of teaching is interactions among students and the instructor. Our classroom experienece and normal campus life is unfortunately being changed to protect everyone's safety and health. In the meanwhile, we want to do whatever we can to overcome the challenges to CS422 and preserve a fruitful learning experience in Spring 2021. As a result, there is no difference for both sections: (1) course participation in the synchronous section is not required but (2) all the students (in both synchronous and asynchronous sections) are encouraged to attend the synchronous section (12:30 pm - 1:20 pm, MWF) to retain classroom-like interactions in CS422.

Online tools and resources

Please login below websites to see more course resources.

TAs and PSOs:

No PSOs in the first week. Please check their PSO links and annoucemnets at Piazza.


Computer Networking: A Top-Down Approach, 7th Edition, J. F. Kurose and K. W. Ross

Other useful books: Computer Networks And Internets, 6th Edition, D. E. Comer Computer Networks: A Systems Approach, 5th Edition, L. Peterson and B. Davie

Course Homepage

This webpage is our official course homepage but serves as the anchor only (no real course materials covered here). We use Piazza to manage real course materials. Please enroll yourself if you haven't. Brightspace is used for you to view your grades and get access to all the online resources.

Course Topics (tentative):


Grading Policy

Course Policy

You need to obey course polices for all the courses in the department of Computer Science, Purdue. Here, I higlhight some important ones.

What is New about COVID-19?

More can be found and updated at Fall 2020/Spring 2021 Resources.

No Late Submissions are Accepted!

All assignments are due on the dates and times specified. It is the responsibility of the students to manage their time so that the assignments can be submitted on time. NO late submissions will be accepted for credits except for a documented severe medical or family emergency (specified below).

Assignment Regrades

If you feel that you have been unfairly graded on a lab assignment, homework or exam, you should petition the appropriate TA or Professor in writing within two weeks of distribution of the graded work. After two weeks, NO regrade requests will be honored. For lab assignments, you are allowed to change a few lines of code if that makes your program work, but there will be a penalty per change.

No Makeup Exams

No makeup exams or quizzes will be given except for a documented severe medical or family emergency.

Academic Dishonesty

We wish to foster an open and collegial class environment. At the same time, we are vigorously opposed to academic dishonesty because it seriously detracts from the education of honest students. Because of this, we have the following standard policy on academic honesty, consistent with Purdue University's official policy and Purdue's Honor Pledge.

It is permissible to discuss a GENERAL METHOD of solution with other students, or to make use of high-level reference materials in the library or online. If you do this, you will be expected to CLEARLY DISCLOSE with whom you discussed the method of solution, or to cite the references used. Failure to do so will be considered cheating or plagiarism. The use of “method of solution” means a GENERAL discussion of technique or algorithm, such as one would reasonably expect to occur standing in front of a whiteboard, and precludes the detailed discussion of code or written assignments.

Specifically, looking at another student's code on his/her computer monitor or copying code from an online source is NOT allowed.

Unless otherwise explicitly specified, all written assignments or code that is submitted is to be ENTIRELY the student's own work. Using any code or copying any assignment from others or from an online source is strictly prohibited without advance prior permission from the instructor. This includes but not limited to the use of code others have submitted in the past, or solutions found on the Internet.

All students work is their own. Students who do share their work with others are as responsible for academic dishonesty as the student receiving the material. Students are not to show work to other students, in the class or outside. Students are responsible for the security of their work and should ensure that printed copies are not left in accessible places, and that filedirectory permissions are set to be unreadable/ to others (e.g. use “chmod -R 700 *” from your home directory. If you need assistance protecting your work, please contact your TAs.

Students who encourage others to cheat or plagiarize, or students who are aware of plagiarism or cheating and do not report it are also participating in academically dishonest behavior.

Be aware that we will use a software tool called MOSS(http:theory.stanford.edu aikenmoss/) to check for copying among submitted assignments. Additionally, the instructor and TA will be inspecting all submitted material to ensure honesty.

Any case of academic dishonesty will be dealt with by a severe grade penalty in the overall class grade (like Failure) and referral to the office of the Dean of Students.

Emergency Policy

In the event of a major campus emergency, course requirements, deadlines and grading percentages are subject to changes that may be necessitated by a revised semester calendar or other circumstances. Any changes will be posted to the course web page or on Piazza. Information about emergency preparedness can be found <a href=“http:www.purdue.eduehpsemergency_preparedness”>here<a>.

If you unfortunately experience a medical or any other form of emergency, please do contact your instructor as soon as possible (usually no later than 3 days within its occurance).


You can also review the policies page maintained by Professor Gene Spafford for additional information about academic honesty and other policies.


If you are experiencing stress or personal problems, Purdue provides counseling services through the Purdue CAPS Center. Please see CAPS for more details.