CS 144: Introduction to Computer Networking

CS 144: Introduction to Computer Networking, Fall 2026

Course basics

Lectures	Mondays & Wednesdays 1:30 p.m.–2:50 p.m. in Gates B1
Lab sessions	Wednesdays, 7:30 p.m.–10 p.m. in CoDa B80
Tutorial sessions	Thursdays or Fridays, starting week 2 (Oct. 1–2). Exception: no tutorial in week 6 after the midterm (Oct. 29–30) Signups for tutorial sessions will be posted on Ed in week 1.
Exams	Midterm: in class (replacing week 6 lab session): Wednesday, October 28, 7:30–9 p.m. (location CEMEX Auditorium) Final: Wednesday, December 9, 3:30 p.m.–5:00 p.m. (location Gates B1)
Calendar	Subscribe to the CS144 calendar
Optional course texts	Kaashoek & Saltzer, "Principles of Computer System Design," Chapters 7–8 (Networks & Fault Tolerance) Kurose & Ross, "Computer Networking: A Top-Down Approach" Peterson & Davie, "Computer Networks: A Systems Approach"
Practice exams	Midterm (2021 Fall) Midterm Answer (2021 Fall) Midterm (2023 Spring) Midterm Answer (2023 Spring) Final (2021 Fall) Final Answer (2021 Fall) Final (2023 Spring) Final Answer (2023 Spring)
Contact	To contact the course staff, please use Ed, the lab sessions, or tutorials. You can also email the instructor in an emergency—I'm here to help but also often behind on email!
Accommodations for disabilities	Please use the submission form to submit OAE letters. Please don't send these via email or Ed. Please note deadlines for the exams (Oct. 7 for midterm, Nov. 11 for final).
Syllabus/logistics	Syllabus/logistics handout
Ed	CS144 on Ed. Please make public posts when possible so answers can benefit anybody. Please don't post source code to lab solutions.
Gradescope	We use Gradescope for some grading. If you cannot enter this website, you may need to first join through Canvas.
Honor Code Discussion	In-class discussion of permissible collaboration

Lecturer

Keith Winstein

Email: Winstein email address

Course Assistants

Aya Aburous
aaburous

Jad Bitar
jadbitar

Gabriel Bo
gabebo

Nicholas Ingino
ningino

Thomas Li
bitset

Michaael Paper
mpaper

Shiv Sundram
shiv1

Grading Weights

Exams

Midterm

20%

Final

20%

Lab

Correctness

20%

Subjective

18% (best 6 out of 8 checkpoints, must do last checkpoint)

Tutorial

Subjective

3% (best 6 out of 8, graded ✔⁺, ✔, ✔⁻, ∅)

Quizzes

16% (best 6 out of 8)

Participation/helpfulness

3%

Lab Assignment

FAQ Answers to common questions about lab assignment.

Checkpoint 0: networking warmup

Out: September 23, due October 4, 11:59 p.m.

Checkpoint 1: stitching substrings into a byte stream

Out: September 30, due October 11, 11:59 p.m.

Checkpoint 2: the TCP receiver

Out: October 7, due October 18, 11:59 p.m.

Checkpoint 3: the TCP sender

Out: October 14, due Nov. 1, 11:59 p.m.

Checkpoint 4: measuring the real world

Out: October 21, due Nov. 8, 11:59 p.m.

Checkpoint 5: down the stack (the network interface)

Out: November 4, due November 15, 11:59 p.m.

Checkpoint 6: building an IP router

Out: November 4, due November 22, 11:59 p.m.

Checkpoint 7: making an Internet + something creative!

Out: November 4, due end of class (December 4, 11:59 p.m.)

Lecture Notes

Week 1 (Sept. 23 only)

Wed

Course intro: stuff you should know about CS144

Week 2 (Sept. 28–Oct. 2)

Mon

Datagrams, encapsulation, and multiplexing

Wed

Reliability from unreliability

Week 3 (Oct. 5–Oct. 9)

Mon

TCP I

Week 4 (Oct. 12–Oct. 16)

Mon

TCP Particulars

Wed

Packet Switching I

Week 5 (Oct. 19–Oct. 23)

Mon

Why Congestion Control?

Lecture notes 🎥 Video I 🎥 Video II

What Congestion Control?

Lecture notes 🎥 Video III

Wed

How Congestion Control

Slides 🎥 Video IV

Week 7 (Nov. 2–Nov. 6)

Mon

Routing

The eras tour of home networking

Lecture notes The eras tour of home networking II