Course Description

15-441 is an introductory course to computer networks. The emphasis will be on the basic performance and engineering tradeoffs in the design and implementation of computer networks. To make the issues more concrete, the class includes several multi-week projects requiring significant design and implementation.

The goal is for students to learn not only what computer networks are and how they work today, but also why they are designed the way they are and how they are likely to evolve in the future. We will draw examples primarily from the Internet. Topics to be covered include: congestion/flow/error control, routing, addressing, naming, multi-casting, switching, internetworking, and network security. Evaluation is based on homework assignments, the projects, and two mid-term exams.

The prerequisite for this course is 15-212 (Principles of Programming). Because this course has a big project component, you must be proficient in C programming on UNIX systems. It is required that you have taken 15-213 and gotten a "C-" or higher since many of the programming skills you will need are taught in that course.

Class Meetings

Monday and Wednesday, 3:30-4:50 pm, DH 1112


Srinivasan Seshan <>, Wean Hall 8212
Mor Harchol-Balter <>, Wean Hall 8119

Teaching Assistants

Umair Shah, Wean Hall 3710,
Justin Weisz, Wean Hall 3604,
Julio Lopez, Wean Hall 8205,
Xavier Appe, Wean Hall 3108,

Office Hours



There is a bulletin board, cyrus.academic.cs.15-441, for the course, where anyone can post messages pertinent to the course. Although these will not be ``official'' messages, you may find the discussions there useful. We encourage you to use this bboard as a class resource. The TAs will be reading this bboard regularly. There is another bulletin board cyrus.academic.cs.15-441.announce, which will be used for class announcements. These will also be posted on the class web page.

Course Polices



Your final grade for the course will be based on the following weights for the individual assignments:

Midterm I will be an in-class, closed-book exam, covering all material up to that point in the course.

Midterm II will be an in-class, closed-book exam, primarily covering material from the second half of the course.


Students are encouraged to talk to each other, to the TAs, to the instructors, or to anyone else about any of the assignments. Any assistance, though, must be limited to discussion of the problem and sketching general approaches to a solution. Each student must write out his or her own solutions to the homeworks. The project handouts have more detailed information about collaboration when working on the projects, but, basically, each programming project group must write their own code and documentation for the programming projects done as a group.

Consulting another student's or group's solution is prohibited, and submitted solutions may not be copied from any source. These and any other form of collaboration on assignments constitute cheating. If you have any question about whether some activity would constitute cheating, please feel free to ask the instructors.

Late Policy

Take project and homework deadlines seriously. Our experience is that students often seriously underestimate the effort involved in programming assignments and projects. If we give you 4 weeks to complete an assignment, there is typically a reason. In the interest of fairness, we have adopted the following lateness policy: