15-641/441 Syllabus

Table of Contents

Course Meetings

  • 1:30 - 2:50 Tuesdays and Thursdays in DH 1212

Course Description

The emphasis in this course will be on the basic performance and engineering trade-offs 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: network architecture, routing, congestion/flow/error control, naming and addressing, peer-to-peer and the web, internetworking, and network security.

-- From the Offical Course Description


15-213, or equivalent, or permission of instructor

Textbook (Optional)

Peterson and Davie, Computer Networks: A Systems Approach

Web site

The course website is http://www.andrew.cmu.edu/course/15-441-f12/, contains a tremendous wealth of resources -- check it often!


Gregory Kesden
7711 GHC
(412) 268-1590 (cell)
Schedule w/Office Hours

Note: Please don't pay too much attention to my office hours. If you'd like to speak to me, try calling me and droping by. Or, if you are a risk taker -- just dropping by, not knowing if I am around.

Sometimes I can be found as gkesden on GTalk, AIM, Yahoo, or Skype

Hui Zhang
9105 GHC
(412) 268-8945
Office hours: 1:00pm - 2:00pm, Mondays


Office hours and locations

  • Onha Choe (ochoe@andrew.cmu.edu)): 5:30-7:30pm on Mondays and Fridays in GHC 4122/4126
  • Yoshihisa Abe (yabe@andrew.cmu.edu: 11:00am - 1:00pm on Wednesdays and 11:00am - 1:00pm on Thursdays in GHC 4122/4126
    • Office hours will be 11:00am - 12:00pm on Wednesday, December 5.

Course Attendance

Attendance is expected at all lectures. You are responsible for everything conveyed during class, even if you are absent. The same is true of recitation.

It is suggested that you make friends with your classmates and establish a study group -- these will provide vehicles by which you can discovery the content of any class you might miss. In the event that you miss class, you should contact one of these individuals promptly to ask for help.

The course staff is not responsible to help you with material or procedural announcements from which you opted out by electively missing class.

Need Help?

I can't stress enough that the course staff are dedicated to providing you the highest possible levels of support: inside of the classroom and outside. Please, if you need help, do ask.

To reach the entire course staff, please email
staff-441@cs. This is a great way to get a fast answer to your questions -- I'll be one of us isn't far from the keyboard.

Assignments and Grading

  • Midterm Exam: 15%
    This will be an individual, in-class, written exam.
  • Final Exam: 20%
    This, too, is a traditional paper-and-pencil exam to be administered during the University final exam period.
  • Homework, &c: 15%
    These are out-of-class written assignments. They are usually individual.
  • Projects: 10% + 20% + 20% = 50%
    These are large, out-of-class programming assignments that are completed with a single partner.

Grade Corrections

We try to be very, very careful about scoring your work and maintaining your grades. But, we are human and will make mistakes. If you have any questions about grading, please see any member of the course staff.

If possible, s/he will help you "on the spot". But, if s/he want to discuss the issue with other members of the staff, which does occur in many cases, he or she might make a copy of your work and/or ask you to write down or email your concerns. Please don't be alarmed -- this is just to try to ensure correctness and consistency among staffers, as well as prevent miscommunication. If you are asked to provide a copy of the work or feedback in question, or to provide your concerns in writing or email, you are required to do this before your concern can be addressed.

Please keep copies of all of your graded work, electronic submissions, and electronci feedback, until you receive your final course grade and are satisifed that it is correct. Without the original work and the grading information, it is more difficult and time consuming to correct errors.

In general, grading concerns should be addressed within one (1) weeks. In the special case of the final exam, they should be addressed with one (1) year. The course staff, at its discretion, may refuse to reconsider grades outside of this time period.

Should concerns arise outside of these time periods, but during the semester, please do contact any member of the course staff -- we want to be reasonable and will do our best, within our discretion, to help. Should concerns occur after the end of the semester, please contact the instructor. Or, in the unlikley event that he is no longer at the University, on leave, or otherwise inaccessible, contact an administrator in the Computer Science department.

Students do have the right to appeal final course grades. This can be done informally, beginning with the instructor, and then to the student's academic dean and/or the academic dean in the home department. It can also be done formally using the policy outline in the Academic Regulations.


It is suggested that you form study groups as soon as possible. These groups generally work best if there are between three and five people involved, but sometimes pairs or slightly larger groups can work well. Typically the most effective study groups meet once per week for a few hours, or a couple of times each week for a couple of hours each meeting. For study groups to be effective, each member must work indivudally with the material in-between meetings such that s/he has something to contribute as well as questions to drive the discussion.

Unless otherwise specified, all assignments should be completed individually. In other words, it is okay to collaborate in studying the course material, but the "writing on the page" or the "code in the lab", as examples, should be your own "thought product".

If portions of your indididual assignments have been significantly influenced by someone else, you should prominently give them credit for their contribution. Proper attribution is critically important -- and is an absolute defense against charges of "Academic Dishonesty"

Failure to provide proper recognition for the contributions of others towards any graded work may be, at the discretion fo course staff, considered Academic Dishonesty under the applicable University, School, Department, and/or Intro Group policies.

The Academic Regulations are the only authoritative source for information regarding the University police on Academic Dishonesty, and related procedural matters. But, the following is an informal summary:

  • An instructor can charge a student with academic dishonesty and impose a penalty within the course, including an "R" grade.

  • The instructor informs the University of the charge, where it is recorded. If it is a first-offense, the University takes no further action. If it is not, a University committee is convened. For other than first offenses, the Committee, not the instructor determines the penalty, which can include academic actions such as expulsion or suspension, as well as less-severe actions. The student may appear at this hearing, and the instructor might also ask to appear or be asked to appear.

  • Even on a first offense, the instructor can ask the University to convene a Committee as discussed above. This might be done, for example, in the case of a particularly flagrant case, or under atypical cicumstances.

  • The student has the right to appeal an instructors finding of academic dishonesty. Such an appeal is heard by the same Committee as discussed above. In the event that both the student and faculty member request a Committee, the same Committee will hear both.

  • University procedure provides for the appeal of decisions by the Committee.

  • In the event that the instructor charges a student with Academic Dishonesty, it is suggested that the student consider the totality of the circumstances calmly and rationally and seek advice from the instructor -- as well as third parties, such as the student's advisor, academic dean, or a dean of student affairs. It is may not be in the student's best interest to take a rash action, such as attempting to drop the course.

  • Students who are charge with Academic Dishonesty should be aware that there will be no prejudice against them in the course, beyond the penalty directly imposed, as a result of the charge, or of any appeal.

Late Work

You have five (4) "Late Days" for use on assignments this semester. You may not turn in the last assignment beyond the last day of classes, regardless of the number of late days you have remaining. You can use one day on each of three assignments, three days on one assignment, &c. There are no half days -- an assignment 1 second late requires the use of a full late day.

These late days are not "procrastination days". They are instead designed much like "personal days" at work to handle the little things that come up during the semester: short illnesses, injuries, visiting family or friends, a burst of work in other classes, doctors vists, &c.

The use of these days is completely at your discretion -- but, once they are gone, they are gone. That's it. The course staff cannot give you more. Late work is not accepted, other than through the use of "Late Days".

There is, of course, the possibility that exceptions to this policy will arise. We certainly hope that nothing incapactiating will happen to any of you. But, in the event that there is some major life event including major medical issues, emotional problems, family problems, &c, the course staff stands ready to work with you, as appropriate.

But, because these events are major events that likely will affect more than one class, we refer these circumstances to other University officials, typically academic deans, deans of student affairs, and/or assigned academic advisors.

In the event that you need help of this kind, please see a member of the course staff, and advisor dean, or other appropriate University offical. If you contact us, we'll likely begin by contacting your advisor or dean. But, regardless who you contact first, we'll work together with your academic unit and/or student affairs, and (most importanbtly) you, to do the Right Thing. We are, in fact, here to help.

Please also keep in mind that assignments only count as submitted, if submitted as directed. For example, we don't accept assignments via email or on thumb drives, unless we specifically authorize it. Should you fail to submit an assignment as directed, you will need to use late days to submit it.

Electronically Mediated Communication - "A.M. Memorial Policy"

You are not permitted to engage in any electronically mediated communication during class - the penalty, even for a first offense, is an "R" in the course. No TXTing. No IMing. No email. No surfing the Web. No net games. No talking on your cell phone. You get the idea: If something is being communicated and anything even vaguely electronic is involved, you flunk. If you are not comfortable with this -- find a different section.

This might seem extreme to you, but it necessary. The ubiquity and pervasiveness of these technologies is threatening the classroom dynamic. Unless it is controlled, it will become cultural - and the loss to education permanent and tremendous. Since it is somewhat difficult to prove allegations of this kind from the front of the classroom, the penalty is severe to act as a deterrent. Other instructors, student assistants, staff members, and/or other trusted individuals may be asked to monitor the classroom from various points of observation to aid in the enforcement of this policy and still photographic evidence may be acquired and used to document violations.

No Email Attachments

Unless otherwise directed by a member of the course staff, do not send files as attachments via email. For technical reasons, this mode of file transmission is extremely inefficient. Instead, please create a directory within your AFS space, place the file or files into that directory, and give gkesden:staff-100 at least "rl" access. If this doesn't make sense to you -- relax. Just send email to us and ask for instructions for sending us the file(s).

Videotaping, audiotaping, still photography prohibited

High-fidelity recordings of class, including any audio and/or video recordings, regardless of the media or format, and regardless of the intended or actual use, are not permitted without prior written permission of the instructor. The class will be notified in advance should any such recording be approved. The penalty for violating this policy is an "R" in the course. If you are not comfortable with this, drop the course now. Students have no right to record classes under any University policy.

This policy is intended to protect the privacy of the students. No student should run the risk of potential employers finding a naown that, excluding special cases such as use by students with disabilities or distance learners, undergraduate students do not improve their performance through the use of high fidelity recordings.