Computer Networks

Course Format

The course will meet twice a week for 80-minute lectures.

Each lecture will contain discussion, activities, and material that assumes that you have watched the preparation videos in advance. Preparation may be tested without warning.

The primary assignments for the course will be lab-based programming assignments. We will also release weekly problem set exercises whose primary purpose is to help in preparation for the midterm and final exam; these problem sets may be graded at random.

Recommended Background

Prerequisite: COS 217. Although not required, taking either COS 318 or 333 before COS 461 is helpful for the programming assignments. Note well: The assignments in this class are in Go, C, and Python. You do not need to have experience with all of these languages before taking the course. However, you should be comfortable with learning new programming languages and finding resources on your own, independently as you attack problems. You will be exposed to new programming languages and environments. If you are not comfortable learning new programming languages and familiarizing yourself with new programming environments on your own, you will have difficulty in this course.

Grading

Grading is based on:

• a midterm (15%)
• a final exam (20%)
• eight programming assignments (8% each)
• participation (Piazza and in-class), in-class quizzes, pencil-and-paper "practice" assignments (1%)

Late Policy

We understand that sometimes life events occur and that it's not always possible to meet every deadline. As such, we are willing to accept late assignments according to the following policy:

• You start the term with a grace period "balance" of 96 hours.
• Each assignment will be due at 5:00 p.m. (Princeton Local Time) on the due date.
• For each assignment, every hour late (or fraction thereof) that you turn in the assignment will subtract one hour from your grace-period balance. For example, if you turn in your assignment at 6:02 p.m. on the due date, we will count this as two hours against your grace period.
• As long as your grace period balance is positive, you can turn in any assignment late without penalty.
• Once your grace period balance reaches zero, you will receive half credit for any assignment that you turn in, as long as you turn it in within one week of the due date. If your grace period balance is zero and you turn in an assignment more than one week late, you will receive no credit for the assignment. Important: You must still turn in all assignments to pass the course, even if you receive zero points on an assignment. Turning in all assignments is a necessary condition for passing.

Excuses with medical documentation are a legitimate exception and will not count against your late period. Any other reasons for lateness---including but not limited to interviews, conferences, etc.---are not legitimate excuses and any resulting lateness will count against your grace period.

Honor Code

Students are expected to abide by the Princeton University Honor Code. Honest and ethical behavior is expected at all times. All incidents of suspected dishonesty will be reported to and handled by the office of student affairs. You are to do all assignments yourself, unless explicitly told otherwise. You may discuss the assignments with your classmates, but you may not copy any solution (or part of a solution) from a classmate.

Reading and Videos

Supplementary Videos: Prof. Feamster's Networking Videos.

Primary Supplementary Textbook: Computer Networking: A Top-Down Approach (6th edition), by Jim Kurose and Keith Ross (Excerpts on Blackboard)

Recommended Books: Other recommended textbooks for reference include:

• Computer Networks: A Systems Approach, Larry Peterson and Bruce Davie
• TCP/IP Illustrated, Volume 1: The Protocols and Unix Network Programming, Volume 1: The Sockets Networking API (3rd Edition)

Purchasing these books is not necessary; they will be on reserve in the engineering library, and online resources will be made available.

This schedule and syllabus is preliminary and subject to change. Suggested reading assignments refer to the Kurose/Ross book (6th edition), unless otherwise specified.

Videos: In addition to the readings, we recommend watching the corresponding videos from the YouTube Playlist, before lecture.

Slides: All slides will be posted on Blackboard before lecture.

Date	Topic	Readings	Notes
February 6	Course Overview Brief History of the Internet	1.1-1.2, 1.7	Programming Assignment 1 (Virtual Machine Setup, Sockets)
February 8	Architectural Principles Packet Switching End-to-End Argument Socket Programming	1.3, 2.7 Beej’s Guide
February 13	Link Layer ARP, Switches Spanning Trees Ethernet, DOCSIS	5.1-5.4
February 15	IP Addressing Classful Addressing Allocation CIDR and LPM IPv6 NAT	4.1,4.4
February 20	Intradomain Routing  Topology  Distance Vector  Link State	4.5	Programming Assignment 2 (Routing Algorithms)
February 22	Interdomain Routing  Route Attributes  Route Selection	4.6.1
February 27	TCP and UDP Reliable delivery Connections	3.1-3.5
March 1	Congestion Control Congestion Collapse TCP Congestion Control Fairness	3.6-3.7
March 6	Router Design Router Architecture Lookup Switching Buffer sizing and bufferbloat	4.3	Programming Assignment 3 (TCP window size and bufferbloat)
Module 2: Network Management
March 8	Queuing and Scheduling Max-min Fairness FIFO Fair Queueing
March 13	Midterm
March 15	DNS Resolution Nameserver hierarchy Record types	2.5	Programming Assignment 4 Released (Measurement)
March 27	Network Management Network Measurement Active measurement Passive measurement Traffic Engineering Intradomain TE Interdomain TE	9.1-9.2
March 29	Traffic Shaping Token Bucket Leaky Bucket	7.5.2
Module 3: Policy and Security
April 3	Communications Policy ISPs and Privacy Peering Disputes Open Internet Order Network Neutrality	ISPs and Privacy	Programming Assignment 5 (Portscan)
April 5	Denial of Service Attacks Overview DDoS Defenses	DNS Amplification (NYT) China’s Great Cannon
April 10	Routing Security Route Hijacks BGPSEC	Routing Security Kapela Route Hijack
April 12	Naming Security Cache Poisoning Amplification Attacks DNSSEC DNS Privacy	pp. 143-144 Kaminsky DNS Attack (Figure) DNSSEC Overview (Slides 1-5)	Programming Assignment 6 (DNS Reflection)
April 17	Botnets and Application-Layer Attacks Viruses and Worms Spam, Phishing Botnets Censorship National firewalls Circumvention tools	Cole: Chapter 19 Tor Overview
Module 4: Applications
April 19	The Web (HTTP) Overview Proxies Caching and Prefetching Web Performance HTTP/2	2.2
April 24	Content Distribution Networks (CDNs) Geo-replication Reverse proxies EDNS Client Subnet Data Center Networking Topologies Routing	7.2.4 Barroso: Chapter 1, 3.3	Programming Assignment 7 (Implementation and Optimziation of HTTP Client and Proxy)
April 26	Streaming Video and Audio Encodings Buffering DASH Peer-to-Peer Networking  BitTorrent Chord	2.6,7.2
May 1	Midterm 2

Course Resources

• Piazza Online Discussion Forum
• Course Blackboard Page
  (Slides, readings, and other course resources will be posted here.)

Go Resources

• Go Language Blog
• defer and exception management
• semaphores
• arrays and slices
• formatting code
• concurreny in practice
• maps
• builtin identifiers
• race detection
• Go Language FAQ
• Go Lecture by Rob Pike
• Packet Processing in Go
• Understanding Go Internals

Software Resources

• Vagrant
• VirtualBox Environment
• Hints on VM Setup
• Official virtual machine image (To be posted.)
• Mininet: Virtual network emulation environment
  • Mininet Walkthrough

Going Further (Optional)

• Various Online Reading from Professor Feamster
• Connection Management Blog: Blog where various topics will be discussed during the course.
• A Research "How To" Blog
• Prof. Feamster's Twitter Feed
• Udacity Course Modules (some may be useful for additional explanation)
• Module 1
• Module 2
• Module 3

Assignments

• Assignment 1: https://github.com/PrincetonUniversity/COS461-Public/tree/master/assignments/assignment1
• Assignment 2: https://github.com/PrincetonUniversity/COS461-Public/tree/master/assignments/assignment2
• Assignment 3: https://github.com/PrincetonUniversity/COS461-Public/tree/master/assignments/assignment3
• Assignment 4: https://github.com/PrincetonUniversity/COS461-Public/tree/master/assignments/assignment4
• Assignment 5: https://github.com/PrincetonUniversity/COS461-Public/tree/master/assignments/assignment5
• Assignment 6: https://github.com/PrincetonUniversity/COS461-Public/tree/master/assignments/assignment6
• Assignment 7: https://github.com/PrincetonUniversity/COS461-Public/tree/master/assignments/assignment7