An introduction to fundamental concepts of computer networks and widely used networking technologies. Topics include application protocol design; principles of congestion and error control protocols; network routing; local, wireless, and access networks; network security; and networking programming. The Internet suite of protocols will be discussed in depth. Students will learn about conventional and state-of-the-art computer networks through problem sets and programming projects. More...

Credits 4
  • CS 231 - Data Structures and Algorithms
  • CS 232 - Computer Organization
  • Or permission of the instructor
Semester Fall 2023
Date Time, Location TR 9:30 - 10:45 am,
DAVI 117
Instructor Ying Li
Office: Davis 111
Office Hours: Mondays and Wednesdays: 2:00 - 3:30; Tuesdays and Thursdays: 11:00 - noon
Course Goals
  1. Students demonstrate an understanding of the fundamental concepts of computer networks and widely-used networking technologies.
  2. Students demonstrate an understanding of the Internet suite of protocols.
  3. Students demonstrate an ability to utilize the commonly used networking tools.
  4. Students demonstrate an ability to analyze the network performance.
  5. Students present methods, algorithms, results, and designs in an organized and competently written manner.
Grading The course grade will be determined as follows:
  • Projects: 50%
  • Midterm: 20%
  • Final Exam: 20%
  • Class Participation: 10%

Projects are designed to provide you with an opportunity to apply the knowledge learned in class. Projects are typically assigned on every other Tuesdays on Moodle. The standard project deadline is at the midnight of the second Tuesday after the assignment.

Every project has two parts: a problem set and a programming assignment. You are expected to finish the problem sets individually and are encouraged to work with a partner on the programming assignments throughout the semester. The purpose of encouraging group work on programming assignments is to let you and your partner get the most out of the assignment (a.k.a. finish the programming assignment better and try more extensions). So, both team members should actively participate in the programming assignments. Feel free to work on both parts individually if you prefer. Please let Ying know whether you will work individually or not on the programming assignments and who will be your partner if you decide to work in a group by the Friday of the second week of class (Sept. 15, 2023).

Projects are graded based on a 50-point scale. The problem set counts 20 points, and the programming assignment counts 30 points. The programming assignment has the required tasks and extensions. If you complete the required tasks well, you can get 26/30. You should finish one or more extensions if you'd like to get 90% or above for your programming assignment. Late programming assignment will receive 26/30. Problem sets will be closed automatically at midnight of the due date. Open attempts will be automatically submitted when time expires. So, handing in something on the due date is generally better than handing in a complete assignment late.

As you all have busy schedules, you may have one four-day extensions you can use at your discretion over the course of the semester, excepting only the final project. That means you may choose to hand in one of the projects on Saturday instead of Tuesday. Please email Ying and let her know that you are taking your extension before the deadline.


The midterm is an opportunity for you to show me your understanding of the course. I will assign a mock exam a week before the midterm to help you study for the exam. You don't need to submit your mock exam; we will discuss it before the midterm. I strongly encourage you to try it before the discussion.

The midterm will be on Tuesday, Oct. 24 during the class time. It is a one-hour exam, and you can bring a letter-size cheatsheet to the exam.

The midterm may be made up when a prior request is made or there is a documented health issue. Be sure to get in touch with me immediately in the event of illness and other unforeseen circumstances; we will work out accommodations.

Final Exam

The final exam will be oral, and you are expected to finish it individually. Exam details will be given in the last class. There are no make-ups for the final exam.

Class Participation

You are expected to attend every lecture and actively join the class discussions. Class discussion is a vital part of the learning experience. A good class discussion needs your contribution.

If you must miss a class, please email me in advance. I'm happy to work with you.

Participation also includes coming to my office hours or sending me emails for help. Don’t hesitate to come to my office hours or email me. I'm happy to help if you let me know your questions.


There is no required textbook for this course. Lecture contents will be in the lecture nodes, and all lecture notes will be posted in the Notes section of the webpage.

The following textbook is recommended if you are interested in consulting an additional resource.

James F. Kurose and Keith W. Ross: Computer Networking: A Top-Down Approach, Eighth Edition, Pearson, 2020, ISBN 978-0136681557.
How to succeed

Projects: Start working on the projects as early as possible. Ask me for help if needed. Talk with your peers about the course concepts.

Midterm: Study for the midterm by doing the mock exam and reviewing the relevant topics in the lecture notes. You are strongly encouraged to try out the mock exam before we discuss the solution in class.

Final Exam: Learn at least two of the topics we discussed in class well enough during the semester, letting yourself feel comfortable talking about these topics. Start working on the exam early after it's assigned.

Participation: Be active in class, asking questions and joining discussions. Come to my office hours. Ask Ying for help if you have questions.

How to get help from Ying I'm happy to help if you let me know your questions or concerns. I will be in my office, Davis 111, waiting for you during my office hours. If I'm not in my office during my office hours, please find me in the robotics lab. If my office hours don't work for you, don't hesitate to let me know. I'm happy to make an appointment with you. Email is another good way to ask me for help. I will reply to your email ASAP. If you don't receive my response 24 hours after sending the email, please don't hesitate to "ping" me. There is nothing wrong with your email. It's just that your email may be buried under a large pile of emails, and yours is very important to me.
Collaboration, Academic honesty

This policy applies to anyone you work with other than your partner.

Computer science, both academically and professionally, is a collaborative discipline. In any collaboration, however, all parties are expected to make their own contributions and to generously credit the contributions of others. In our class, therefore, collaboration on homework and programming assignments is encouraged, but you as an individual are responsible for understanding all the material in the assignment and doing your own work. Always strive to do your best, give generous credit to others, start early, and seek help early from both your professors and classmates.

The following rules are intended to help you get the most out of your education and to clarify the line between honest and dishonest work. We reserve the right to ask you to verbally explain the reasoning behind any answer or code that you turn in and to modify your project grade based on your answers. It is vitally important that you turn in work that is your own. We do use automated plagiarism detection software, so please be sure to abide by these, rather minimal, rules. Reports of academic dishonesty are handled by an academic review board and a finding of academic dishonesty may result in significant sanctions. For more details on Colby's Academic Integrity policies and procedures, see

  • If you have had a substantive discussion of any programming project with a classmate, then be sure to cite them in your report. If you are unsure of what constitutes "substantive", then ask me or err on the side of caution. As one rule of thumb, if you see more than 10 lines of someone else's code, then you should cite them. You will not be penalized for working together.
  • You must not copy answers or code from another student either by hand or electronically. Another way to think about it is that you should be talking English with one another, not program languages.

You can use ChatGPT to address your problems when you are stuck with your projects at some point. But, you are not expected to use ChatGPT to generate answers or programs and use them for your projects directly. If you used ChatGPT to assist with your projects, you should acknowledge the part you used ChatGPT at the end of the assignments. Not doing so breaches academic integrity policies. It's your responsibility to verify the correctness of the information provided by ChatGPT. You will not lose points for claiming you used ChatGPT to help you solve the problems. But you will lose points for incorrect answers.

The Colby Affirmation

Colby College is a community dedicated to learning and committed to the growth and well-being of all its members.

As a community devoted to intellectual growth, we value academic integrity. We agree to take ownership of our academic work, to submit only work that is our own, to fully acknowledge the research and ideas of others in our work, and to abide by the instructions and regulations governing academic work established by the faculty.

As a community built on respect for ourselves, each other, and our physical environment, we recognize the diversity of people who have gathered here and that genuine inclusivity requires active, honest, and compassionate engagement with one another. We agree to respect each other, to honor community expectations, and to comply with College policies.

As a member of this community, I pledge to hold myself and others accountable to these values. More ...

Title IX Statement

Colby College prohibits and will not tolerate sexual misconduct or gender-based discrimination of any kind. Colby is legally obligated to investigate sexual misconduct (including, but not limited to, sexual assault and sexual harassment) and other specific forms of behavior that violate federal and state laws (Title IX and Title VII, and the Maine Human Rights Act). Such behavior also requires the College to fulfill certain obligations under two other federal laws, the Violence Against Women Act (VAWA) and the Jeanne Clery Disclosure of Campus Security Policy and Campus Statistics Act (Clery Act). To learn more about what constitutes sexual misconduct or to report an incident, see:

I am committed to all Colby students feeling safe, accepted, and included in all aspects of their college experiences, including this course. Colby prohibits and will not tolerate sexual misconduct or gender based discrimination of any kind and is obligated, by federal and state laws, to respond to reports and provide resources to students. As your professor I am considered a "responsible employee" which requires me to report incidence of sexual misconduct, dating violence, or harassment to the Title IX Coordinator.

If you wish to access confidential support services, you may contact:

  • The Counseling Center: 207-859-4490
  • The Title IX Confidential Advocate, Emily Schusterbauer: 207-859-4093
  • The Office of Religious and Spiritual Life: 207-859-4272
  • Maines's 24/7 Sexual Assault Helpline: 1-800-871-7741
Religious Holidays

Colby College supports the religious practices of students, faculty, and staff, but we don't always know which people will observe which holidays. Since I need to plan course activities in advance, I need to know in advance, if you need to miss a class or have a deadline adjusted in order to observe a holiday. Please notify me by email at least 14 days in advance of any religious holiday that will affect your ability to participate in this course.

© 2023 Ying Li. Page last modified: 08/31/2023