Class Info

Class: TuTh 2:40–3:55, Science Center 101
Professor: Kevin Webb
Piazza: Q&A Forum
GitHub: Swarthmore GitHub Enterprise
Gradesource: Anonymized Grade Listings
Office hours: W 11:00 AM - Noon, Th Noon - 2:00 PM
Office: Sci 255

Welcome to CS43. This course will introduce fundamental ideas in computer networking. The structure of this course may be different from many other CS courses at Swarthmore. We'll be using a teaching model called Peer Instruction, which places a strong emphasis on classroom discussion and student interaction.

The course is composed of the following:

• Readings: The readings serve as a first exposure to new topics, where students learn the basics of the material.
• Class meetings: The classroom material will cover the difficult concepts and facilitate student discussions.
• Labs: There are several lab programming assignments (mostly in C) that will explore various aspects of network programming.
• Exams: There is a midterm exam and a final exam (both closed-book) covering the material in the class meetings and labs.

Required Textbook & Clicker:

Computer Networking: A Top-Down Approach by Kurose and Ross
ISBN: 978-0133594140
We'll be using the seventh edition.

iClicker device: This course will use clickers to facilitate feedback and discussion during class. For many upper level courses including CS43, we are now requiring that students purchase their own clicker for personal use. Clickers may be purchased at the college bookstore or online. You must also register your clicker online.

Goals for the course:

By the end of the course, we hope that you will have developed the skills to:

• Classify network functionality into the appropriate abstraction layer.
• Characterize the behavior of popular network applications and protocols (HTTP, SMTP, DNS, etc.).
• Construct distributed applications using various concurrency models.
• Design and analyze network application protocols.
• Identify the role of transport protocols in providing reliability and high performance.
• Implement routing algorithms and analyze routing protocols.
• Compare and contrast switching and forwarding platforms.
• Test and debug networked applications.

Schedule

This is a tentative schedule; it may change as we go. You should read the assigned sections before class to prepare for the reading quiz. All readings refer to the Kurose and Ross textbook unless otherwise indicated (e.g., there's a link to some other source).

WEEK	DAY	ANNOUNCEMENTS	TOPIC & READING	LAB	AUDIO
1	Sep 05		Course introduction	Lab 1	Audio
	Sep 07		Internet/OSI Models and layering Reading: 1.1, 1.5		Audio
2	Sep 12		HTTP and the Web Reading: 2.2		Audio
	Sep 14		Structure, threading, and blocking Reading: pthreads and Beej 7.1: Blocking		Audio
3	Sep 19		Network applications and distributed systems Reading: 2.1	Lab 2	Audio
	Sep 21		Naming and DNS Reading: 2.4		Audio
4	Sep 26		Email and SMTP Reading: 2.3		Audio
	Sep 28		BitTorrent, DHTs, and CDNs Reading: 2.5 - 2.6.3		Audio
5	Oct 03		Transport services, UDP Reading: 3.1, 3.3	Lab 3	Audio
	Oct 05		Reliable transport Reading: 3.4		Audio
6	Oct 10		Reliable transport in TCP Reading: 3.5 - 3.5.4		Audio
	Oct 12		Reliable transport in TCP (continued)		Audio
	Oct 17	Fall Break
	Oct 19
7	Oct 24		Midterm information + Q&A	Lab 4	Audio
	Oct 26		Midterm		N/A
8	Oct 31		Flow and congestion control Reading: 3.6 (Skip 3.6.1), 3.7		Audio
	Nov 02		Network layer introduction Reading: 4.0 - 4.2.1		Audio
9	Nov 07		IP Reading: 4.3 - 4.3.3	Lab 5	Audio
	Nov 09		NAT, ICMP, IPv6 Reading: 4.3.4 - 4.3.5, 5.6		Audio
10	Nov 14		Routing algorithms Reading: 5.2 + very beginning of 5.3 (before OSPF)		Audio
	Nov 16		Routing on the Internet Reading: 5.3 (from OSPF) - 5.4	Lab 6	Audio
11	Nov 21		Traffic management Reading: 4.2.3 - 4.2.5, 9.5 - "The Leaky Bucket")		Audio
	Nov 23	Thanksgiving Reading
12	Nov 28		Link layer Reading: 6.1 - 6.2		Audio
	Nov 30		Media access Reading: 6.3 - 6.3.3	Lab 7	Audio
13	Dec 05		Switches and LANs Reading: 6.4 - 6.4.3		Audio
	Dec 07		End-to-end Example		Audio
14	Dec 12		Security Reading: 1.6, 8.2.0, 8.2.2		Audio
	Dec 15	Final Exam 9:00 - 12:00 AM, in SCI 199

Lab Policy

This course features regular lab assignments that account for the largest component of your course grade. Lab attendance is required by all students, unless you have already completed and submitted the lab assignment for the week. Additionally, the cs labs are open 24 hours a day, 7 days a week for you to use for CS43 lab assignments. While you must attend the lab session for which you are registered, you may optionally attend additional lab sessions, provided space is available. In case of space constraints, students registered for the lab will have seating priority.

Lab assignments will typically be assigned during the lab sections on Friday will generally be due by midnight on Thursday 1-2 weeks later. You are strongly encouraged to start early!

Even if you do not fully complete an assignment, you should submit what you have done to receive partial credit.

Weekly Lab Sessions
Section 1	Fridays 2:15—3:45	Science Center 256
Section 2	Fridays 4:00—5:30	Science Center 256

Accessing the CS labs after hours

You can use your ID to gain access to the computer labs at nights and on the weekends. Just wave your ID over the onecard reader next to the lab doors. When the green light goes on, just push on the door handle to get in (the door knob will not turn). If you have issues with the door locks, send an email to local-staff@cs.swarthmore.edu. If the building is locked, you can use your ID to enter the door between Martin and Cornell library. For this class, your ID will give you access to the labs in rooms SCI 238, 240, 256, and Clothier basement.

Grading

Grades will be weighted as follows:

35%	Lab assignments (3%, 5%, 5%, 6%, 5%, 5%, 6%)
30%	Final Exam
25%	Midterm Exam
5%	Reading Quizzes (I will drop your three lowest quizzes.)
5%	Class Participation

Absence / Assignment Extension Policy

To help with cases of minor illnesses, athletic conflicts, or other short-term time limitations, we will drop your three lowest reading quizzes and participation grades. You are still responsible for the material, and you should review any missed materials via the class recordings as soon as you can.

All students start the course with two "late assignment days" to be used at your discretion, with no questions asked. To use your extra time, you must email your professor after you have completed the lab and pushed to your repository. You do not need to inform anyone ahead of time. When you use late time, you should still expect to work on the newly-released lab during the following lab section meeting. The professor will always prioritize answering questions related to the current lab assignment.

Your late days will be counted at the granularity of full days and will be tracked on a per-student (NOT per-partnership) basis. That is, if you turn in an assignment five minutes after the deadline, it counts as using one day. For partnered labs, using a late day counts towards the late days for each partner. In the rare cases in which only one partner has unused late days, that partner's late days may be used, barring a consistent pattern of abuse.

If you feel that you need an extension on an assignment or that you are unable to attend class for two or more meetings due to a medical condition (e.g., extended illness, concussion, hospitalization) or other emergency, you must contact the dean's office and your instructors. Faculty will coordinate with the deans to determine and provide the appropriate accommodations. Note that for illnesses, the College's medical excuse policy, states that you must be seen and diagnosed by the Worth Health Center if you would like them to contact your class dean with corroborating medical information.

How to Succeed in CS 43

• Read the material before you come to class.
  Don't worry about total comprehension, but at least get a feel for what we will be covering that week. If you have some understanding of the material coming into class, it will be easier for you to ask questions during class, rather than later when help may not be available.
• Attend class and participate in discussions.
  In class, we'll cover new topics and dig into the more challenging details of the material. Class discussions are a critical part of the learning process, as these exercises give you immediate experience with the material we are covering. Also, we'll have frequent reading quizzes, so you need to be present!
• Ask questions if you don't understand.
  This means both during class and while doing lab assignments. This class continually builds on previous material, so if you don't understand something one week, it will continue to be a problem the next week, and the week after that, and so on. If you need help, ask your classmates (make sure you have read the "Academic Integrity" section below first), post on Piazza, or come talk with me during my office hours.
• Start the lab assignments early.
  I realize this one is not always easy to do, but if you can get in the habit of doing this, you will be much better off. If you get stuck early (i.e., not two hours before it is due), there will be time to look for help. In addition, if you start early enough, you can take a break, go do something else, and come back later. I find I always have at least a few new ideas when I come back to a problem after a break. If you wait until the last minute, you can't do this.
• Practice, practice, practice.
  The only effective way to learn the material and pass the quizzes and exams is to consistently do the labs. Finish all of the assigned programs (and do some extras, for fun!). Even if you don't get them done on time, they will still help you learn the material.
• Seek help early and often.
  Because course material builds on previous material, it is essential to your success in this class that you keep up with the course material. If you are having difficulty with a programming assignment, if you didn't follow something covered in class, if you feel you need some extra help understanding or practicing some of the course material, or if you just want to discuss something from a class, an assignment, or the text, please come to my office hours.
• Attend CS43 Labs.
  Lab attendance is required, and the labs constitute the largest portion of your grade. You should be there!

Academic Integrity

Academic honesty is required in all your work. Under no circumstances may you hand in work done with (or by) someone else under your own name. Your code should never be shared with anyone; you may not examine or use code belonging to someone else, nor may you let anyone else look at or make a copy of your code. This includes, but is not limited to, obtaining solutions from students who previously took the course or code that can be found online. You may not share solutions after the due date of the assignment or make them publicly available anywhere (e.g. public GitHub repository).

Discussing ideas and approaches to problems with others on a general level is fine (in fact, we encourage you to discuss general strategies with each other), but you should never read anyone else's code or let anyone else read your code. All code you submit must be your own with the following permissible exceptions: code distributed in class, code found in the course text book, and code worked on with an assigned partner. In these cases, you should always include detailed comments that indicates on which parts of the assignment you received help, and what your sources were.

Failure to abide by these rules constitutes academic dishonesty and will lead to a hearing of the College Judiciary Committee. According to the Faculty Handbook: "Because plagiarism is considered to be so serious a transgression, it is the opinion of the faculty that for the first offense, failure in the course and, as appropriate, suspension for a semester or deprivation of the degree in that year is suitable; for a second offense, the penalty should normally be expulsion."

The spirit of this policy applies to all course work, including code, homework solutions (e.g., proofs, analysis, written reports), and exams. Please contact me if you have any questions about what is permissible in this course.

Academic Accommodations

If you believe that you need accommodations for a disability, please contact the Office of Student Disability Services (Parrish 113W) or email studentdisabilityservices@swarthmore.edu to arrange an appointment to discuss your needs. As appropriate, the office will issue students with documented disabilities a formal Accommodations Letter. Since accommodations require early planning and are not retroactive, please contact the Office of Student Disability Services as soon as possible. For details about the accommodations process, visit the Student Disability Service website.

You are also welcome to contact me privately to discuss your academic needs. However, all disability-related accommodations must be arranged through the Office Of Student Disability Services.

External Links

Links that are related to the course may be posted here. If you have suggestions for links, let me know.

Beej's Guide to Network Programming