Communication Networks Spring 2022

News

July 8 An additional exercise sheet is now online to prepare for the exam.
June 1 Materials for the last (!) exercise session are now online.
May 29 Materials for the last (!) lecture are now online.
May 23 Materials for the twelfth exercise session are now online.
May 22 Materials for the thirteenth lecture are now online.
May 18 Materials for the eleventh exercise session are now online.
May 18 The missing exercise session on May 26 is replaced by a transport project Q&A on Tuesday May 24, 4 - 6 pm, in ETA F 5.
May 15 Materials for the twelfth lecture are now online.
May 12 Materials for the tenth exercise session are now online.
May 8 Materials for the eleventh lecture are now online.
May 5 Materials for the ninth exercise session are now online.
May 1 Materials for the tenth lecture are now online.
Apr 28 Materials for the eighth exercise session are now online.
Apr 24 Materials for the ninth lecture are now online.
Apr 13 Materials for the seventh exercise session are now online.
Apr 10 Materials for the eighth lecture are now online.
Apr 8 Slides and recording for the Connectivity Fäscht are now online.
Apr 6 Materials for the sixth exercise session are now online.
Apr 2 Materials for the seventh lecture are now available. Note that this lecture will take place exceptionally online (see email).
Mar 30 Materials for the fifth exercise session are now online.
Mar 26 Materials for the sixth lecture are now online.
Mar 24 Materials for the fourth exercise session are now online.
Mar 21 Date of the Connectivity Fäscht: April 7.
Mar 20 Materials for the fifth lecture are now online.
Mar 16 Materials for the third exercise session are now online.
Mar 12 Materials for the fourth lecture are now online.
Mar 10 Materials for the second exercise session are now online.
Mar 2 Materials for the first exercise session are now online.
Feb 27 Materials for the second lecture are now online.
Feb 21 Materials for the first lecture are now online.
Jan 19 Website for 2022 goes live!
Stay tuned for more content

Timeline

Contact

Instructor: Prof. Laurent Vanbever

Research group: Networked Systems Group

Contact:

Assistants:

Chat room: comm-net22.slack.com

Location & time

Lecture: Monday 10 am–12 pm in HG E 1.2

Exercise sessions: Thursday 10 am–12 pm in HG E 1.2

Remote participation: Live stream and recordings

Learn how the Internet works and how to operate it

It is hard to think of a technology that has more changed the way we live than the Internet. From the very way we communicate, access and exchange information, shop, pay, move, entertain, maintain friendship. At the same time, the Internet is inexorably growing, at an always faster pace: from 3 billion of connected hosts in 2015 to an estimated 4 billion in 2019.

At the end of this course, you will be able to:

  1. understand how the Internet works: from your laptop to Google's datacenter at the other end of planet;
  2. build and operate an Internet-like network infrastructure;
  3. identify the right set of metrics to evaluate the performance or the adequacy of a network and propose ways to improve it (if any).

The course is an introductory one, meaning no prior networking background is needed. The course will include some programming assignments (in Python) for which the material covered in Computer Engineering (227-0013-00L) will be useful.

Grading and organization

The class will be graded 70% based on the final exam and 30% based on continuous performance assessments. The continuous performance assessments will consist in two graded group projects. The first project counts for 20% and the second for 10% of the final grade. If a student does not do/submit a project, he/she will receive a grade of 1.0 for the corresponding project. Students repeating the course can decide at the beginning of the semester if they want to keep the previous grades of their continuous performance assessments (more details). The final exam is a written open book exam. You will not be tested on material we didn't cover during the lesson. All written material (books, notes, lab exercises etc.) is allowed; all electronic devices are prohibited, except for (non-connected) calculators. The exam will be in English.

We will use the textbook Computer Networking: A Top-Down Approach (6th Edition) by Kurose and Ross as a reference and as a source of examples. Older versions of the book are fine too but sections number won't necessarily match.

Exercises and projects

In addition to the lectures, there will be a set of exercises (every Thursday) along with two projects to be done in groups of maximum 3 students (the composition of which will be decided by the students themselves at the beginning of the first project).

  1. Internet Routing (middle of the semester): You'll build and operate your own network! We'll then interconnect networks together and form a mini-Internet. We'll test out your Internet during a large class-wide Internet Hackathon.
  2. Reliable Communication (end of the semester): You'll implement a simple transport protocol that can ensure reliable transmission.

Each project will be available online and will be introduced in class along with instructions on the report and on the specific grading scheme.

You should submit your work on an assignment (via your GitLab repository, according to the assignment instructions) before its due time. All assignments are due by 11:59pm on their selected days. If you submit your work late, we will give you credit for it according to this scale:

  • 80% for work submitted up to 1 day late;
  • 70% for work submitted up to 2 days late;
  • 60% for work submitted up to 3 days late;
  • 50% for work submitted up to 7 days late;
  • 0% for work submitted more than 7 days late.

Important If you don't have a laptop, please us at the beginning of the course.

Part 1
Overview and Conceptual Foundations
Week 1
Feb 21 Lecture 1 Introduction (Part 1)
  1. What is a network made of?
  2. How is it shared?
  3. How is it organized?
  4. Brief historical overview
Materials
Homework
  • Take a look at what the Internet looks like!
  • Check out SWITCH (ETH's provider) connectivity and traffic
  • Use the traceroute command (tracert on Windows) to observe some Internet paths taken from your your personal computer to some Internet destination. What do you observe?
Book
  • Sections 1.1 (The Internet), 1.2 (The Network Edge) and 1.3 (The Network Core)
Optional read Optional watch
Exercises start in week 2
Week 2
Feb 28 Lecture 2 Introduction (Part 2)
  1. How does network communication happen?
  2. How do we characterize a network?
  3. How do we guide IP packets from a source to a destination on the Internet?
Introduction materials
Week 3
Mar 7 Lecture 3 Routing Foundations
Materials
Book
  • Sections 4.5.1 (LS Routing Algorithm) and 4.5.2 (DV Routing Algorithm)
Optional watch Optional read
Mar 10 Exercise 2
Part 2
Today's Internet
Week 4
Mar 14 Lecture 4 Ethernet & Switching
Materials
Book
  • Section 5.1 (Introduction to the Link Layer)
  • Section 5.3 (Multiple Access Links)
  • Section 5.4 (Switched LANs)
Optional read
Mar 17 Exercise 3
Week 5
Mar 21 Lecture 5 Internet Protocol (IP) & Forwarding
Materials
Book
  • Section 4.1 (Introduction to the the Network Layer)
  • Section 4.3 (What's Inside a Router)
  • Section 4.5 (The Internet Protocol)
Optional read Optional watch
Mar 24 Exercise 4
Week 7
Apr 4 Lecture 7 online/Zoom-based Routing Policies
Materials
Apr 7 Exercise 6
Apr 7 Connectivity Fäscht

The Connectivity Fäscht will take place in HG E7 and start at 6pm.

Week 9
Apr 18 no class Easter Monday
Apr 21 no exercise Easter Holiday
Week 10
Apr 25 Lecture 9 Reliable Transport Foundations
Materials
Book Book
  • Section 3.4 (Principles of Reliable Data Transfer)
Homework
Apr 28 Exercise 8
Apr 29 Internet Routing project ends
Week 11
May 2 Lecture 10 Transport Layer: UDP and TCP
Materials
Book
  • Section 3.5 (Connection-Oriented Transport: TCP)
Week 12
May 9 Lecture 11 Congestion Control
Materials
Book
  • Section 3.6 (Principles of Congestion Control) and 3.7 (TCP Congestion Control)
Optional read
May 12 Exercise 10
Week 13
May 16 Lecture 12 Applications: DNS
Materials
Book
  • Section 2.5 (DNS. The Internet's Directory Service)
Optional read
  • Take a quick look at the content of old HOSTS.txt files, the ancestor of the DNS
Homework
  • Perform a few DNS lookups for your favourite domains using dig (on a UNIX system) or nslookup (on a Windows system). Look for different records (e.g., A for IPv4 addresses, AAAA for IPv6 ones, NS for delegated DNS servers)
May 16 Reliable Transport project starts
May 19 Exercise 11
Week 14
May 23 Lecture 13 Applications: HTTP
Materials
Book
  • Section 2.2 (The Web and HTTP)
May 24 Q&A session and Exercise 12

Replacement exercise session in ETA F 5, 4-6 pm.

May 26 no exercise Ascension Day
Week 15
May 30 Lecture 14 Recap and Exam Briefing
Materials
Jun 2 Exercise 13
Jun 3 Reliable Transport project ends
Jul 8 Additional Exam Preparation

Exam

The final exam is a written open book exam. You will not be tested on material we didn't cover during the lesson. All written material (books, notes, lab exercises etc.) is allowed; all electronic devices are prohibited, except for (non-connected) calculators. The exam will be in English.

Previous exams

We provide the previous exams (without solutions):