Computer Networking • CS 414 & CS 514

Spring 2013

Table of Contents

Course Description

This a course on computer networking, CS 414 for undergraduate students and CS 515 for graduate students. Unless otherwise mentioned explicitly, everything in this note applies to both CS 414 and CS 514. The course is divided into six two-week sections. See the schedule for details.

The prerequisite for CS 415 is Computer Architecture (CS 286). The prerequisite for CS 515 is Theoretical Foundations of Computer Science (CS 502). A good understanding of operating systems (CS 438 or CS 505) is also helpful.

The class meets in Howard Hall 316 (the computer science conference room) on Mondays and Thursdays from 1:00 pm to 2:50 pm. Classes start on Thursday, 24 January. Undergraduate midterm grades are due on Tuesday, 12 March. Monday, 1 April, is the last day for withdrawing from the class with a W. There are no classes during Spring Break, Monday and Thursday, 18 and 21 March. Classes end on Monday, 6 May.


Learn about computer network design, implementation, and operation. Emphasis placed on medium access control and MAC-layer protocols, the network, transport and TCP/IP, and session layers.

Diligence and perseverance in this class should move you in a direction to eventually be able to


R. Clayton, Howard 318, Office hours are Mondays and Thursdays, 12:00 p.m. to 1:00 p.m. in HH 318. I'm also usually happy to talk to you any time you can catch me; setting up an appointment is recommended, see my schedule for details.


There are three tests, one every two sections starting with section 2; see the schedule. Tests are given in class, and are open book with notes; calculators and computers are not necessary. The tests are cumulative, covering everything taught up to and including the class before the test. Tests should take no more than an hour to complete, and will be given in the first half of the class. Test answers will be made available off the schedule. There are no mid-term or final exams.

There are six homework assignments, one per section starting with section 2 and ending with section 7. Homework problems will be available at the start of the section and are due at the end of the section (that is, by 1:00 p.m. of the last Monday of the section).

The final grade is a straight, unweighted average of the three test grades and the five highest homework grades — the lowest of six homework grades is dropped. The final grade comprises eight grades total; each constituent grade constitutes one-eighth (12.5%) of your final grade.

I use the usual grade ranges:

CS 414: CS 514:
95 A
90 A-<95
83.3B <86.6
80 B-<83.3
73.3C <76.6
70 C-<73.3
60 D<70
95 A
90 A-<95
83.3B <86.6
80 B-<83.3
73.3C <76.6
70 C-<73.3

All grades are kept with one digit of precision to the right of the decimal point and 0.05 rounded up. No grades are adjusted to a curve; that means that 89.9 is always B+, never an A-.

The final grades.

Pop Quizzes

Pop quizzes occur spontaneously. A pop quiz is no more than five minutes long, and is given as soon as the class period starts. A pop-quiz grade ranges from 0 to 5 (inclusive on both ends) and is unappealable; see the pop-quiz rules for full details.



There are many computer networks textbooks, all more or less the same. This course has a textbook, but it doesn’t have an assigned textbook. Instead, pick a textbook or two you’re comfortable with. As a first cut, compare the book’s table of contents with the schedule to make sure the topics mentioned in the schedule appear in the table of contents. You can glean further advice from a small annotated bibliography of computer networks books.

Please do not interpret “There’s no assigned textbook for this course” to mean “Great! I don’t need a textbook.” Absorbing everything you need to know from lectures won’t be possible, not the least because there won’t be time to cover everything in lectures. Working it out over a textbook or two will give you the time and space to learn what you need to know. In addition, the tests are written assuming knowledge found in basic computer networks textbooks.


You should feel free to send me e-mail. Unless I warn you beforehand, I'll usually respond within a couple of hours; if I don't respond within a day, resend the message.

Mail relevant to the class will be stored in a hyper-mail archive ( ). If your message is of general interest to the class, I'll store it, suitably stripped of identification and along with my answer, in the archive.

Home page

This is the class home page; if you’re reading this on paper, you can also find it at ( ). I’ll make the class notes, assignments, and tests available off the schedule at ( ); you should get in the habit of checking the schedule regularly.


The lectures for this class will be recorded and made available via on the mucscn channel ( , rss feed ). Screencasting is experimental, and lecture availability will most likely be unreliable.


Follow the course on ( , rss ) or twitter ( ). The same messages appear on both services. Despite their names, these feeds are for CS 414 and CS 514.



People who need assistance or accommodations above and beyond what is usually provided in class should contact the University’s ADA/504 coordinator to get those needs met. See the Disability Services page for more details.


I have no class attendance policy; you may attend class or not as you see fit. However, I hold you responsible for knowing everything that goes on in class; “I wasn’t in class for that.” is not an acceptable excuse for a wrong answer, or for giving no answer at all.

My attendance policy applies only to lecture attendance; it does not apply to other kinds of attendance which may be required for the course. Repeated failures to meet the attendance expectations set for tests, meetings, projects, labs or other forms of course work will have a bad influence on your grade.


I deal with suspected cheating by failing first and asking questions later. Although cheating has many forms, I generally consider cheating to be any attempt to claim someone else’s work as your own; also, I consider both the provider and the user of the work guilty of cheating. See the chapters on Academic Information and the Student Code of Conduct in the Student Handbook for more details.

Complaining about Grades

I recognize and encourage a student’s sacred right to complain about their grade. There are, however, a few rules under which such complaining should take place, and those students who don’t follow the rules will be less successful in their complaints than those students who do follow the rules.

First, the only complaint that matters is that something got marked wrong when it was actually right. When you come to complain, be prepared to present, in explicit detail, what it is you did and why you think it’s right.

Second, complaints about a particular test or assignment are only valid until the next test or assignment is due; after that point the book is permanently closed on all previous test or assignment grades.

Late Assignments

Assignments should be turned in by their due date; assignments turned in after their due date are late. You should contact me as soon as possible if you need to negotiate a due-date extension. The longer you wait to negotiate, the less likely it is you’ll be successful; in particular, you have almost no chance of getting an extension if you try for one the day before the due date, and you have no chance of getting an extention on the due date.

A late assignment is penalized ten points a day for each day it’s late. I use a 24-hour clock running from midnight to midnight to measure days; note this means that an assignment handed in the day after it’s due is penalized ten points: five for the day it was due and five for the next day.

Missing Tests

There may occasionally be a conflict between taking a test and doing something else, particularly among those working full time. If you’re going to be out of town, or on jury duty, or whatever, on a test day, let me know beforehand and we’ll discuss a make-up test.

A make-up test must be scheduled to be taken by the date of the test following the missed test (or the final exam if you miss the last test). If a missed test is not made up by the time of the next test, you get a zero for the missed test.

There will be only one make up given per missed test. If more than one person misses the same test, those people will have to coordinate among themselves to pick a mutually agreeable date for the make up.


Learn computer networks from the comfort of your home courtesy of the Computer Science and Engineering department (including David Wetherall) at the University of Washington and Coursera.

The last time I taught this course.

This page last modified on 2013 January 20.