Computer Networks


  • Course: Computer Networks (CO20-320301)
  • Semester: Spring 2019
  • Instructor: Jürgen Schönwälder
  • TA: Granderath, Malte
  • TA: Shrestha, Aavash
  • Class: Monday, 09:45-11:00, Lecture Hall Research I
  • Class: Friday, 09:45-11:00, Lecture Hall Research I
  • Office: Monday, 11:15-12:30 (Research I, Room 87)


The course discusses network protocols in some depth in order to enable students to understand the core issues involved in network protocol design. Fundamental algorithms and principles are explained in the context of existing IEEE / Internet protocols in order to demonstrate how they are applied in real-world scenarios. This course is recommended for all students with a strong interest in communication networks and distributed systems.

The course covers topics such as local area networks (IEEE 802), Internet protocols, routing algorithms and protocols, flow and congestion control mechanisms, data representation, application layer protocols, remote procedure calls, network security.


  • Andrew S. Tanenbaum, "Computer Networks", 4th Edition, Prentice Hall, 2002
  • William Stallings, "Data and Computer Communications", 6th Edition, Prentice Hall, 2000
  • Fred Halsall, "Data Communications, Computer Networks and Open Systems", 4th Edition, Addison-Wesley, 1996
  • Christian Huitema, "Routing in the Internet", 2nd Edition, Prentice Hall, 1999
  • William Richard Stevens, "TCP/IP Illustrated Volume 1: The Protocols", Addison Wesley, 1994
  • Douglas Comer, "Internetworking with TCP/IP Volume 1: Principles Protocols, and Architecture", 4th Edition, Prentice Hall, 2000
  • James F. Kurose, Keith W. Ross, "Computer Networking: A Top-Down Approach Featuring the Internet", 3rd Edition, Addison-Wesley 2004
  • Olivier Bonaventure, "Computer Networking: Principles, Protocols and Practice", 2nd Edition, online
  • Peter L. Dordal, "An Introduction to Computer Networks", online


Mo 09:45 Fr 09:45 Topics
2019-02-04 2019-02-08 Introduction, Internet Concepts and Principles, Internet Services Today
2019-02-11 2019-02-15 Media Access Control, Cyclic Redundancy Checks
2019-02-18 2019-02-22 Flow and Congestion Control, OSI 7-Layer Model
2019-02-25 2019-03-01 Local Area Networks (Ethernet, Bridges, VLANs, Port Access Control, WiFi)
2019-03-04 2019-03-08 Internet Network Layer (IPv6/IPv4)
2019-03-11 2019-03-15 Internet Routing Protocols (RIP, OSPF, BGP)
2019-03-18 2019-03-22 Internet Routing Protocols (BGP)
2019-03-25 2019-03-29 Internet Transport Layer (UDP/TCP)
2019-04-01 2019-04-05 Internet Transport Layer (UDP/TCP)
2017-04-08 2019-04-12 Firewalls, Network Address Translators
2019-04-15 2019-04-19 [Spring Break]
2019-04-22 2019-04-26 Domain Name System (DNS)
2019-04-29 2019-05-03 Electronic Mail (SMTP, MIME, IMAP, DKIM)
2019-05-06 2019-05-10 World Wide Web (HTTP)
2019-05-13 2019-05-17 Voice over IP (RTP, SIP)


Date/Due Name Topics
2019-02-15 Quiz #1 Internet concepts, design principles, structure and growth; computer network classiciation and terminology
2019-02-22 Sheet #1 ping, traceroute, iperf, mininet (,,
2019-03-01 Quiz #2 media access control, transmission error detection, flow control and congestion control, OSI reference model
2019-03-08 Sheet #2 bridge spanning tree, wireshark (trace.pcap.gz)
2019-03-15 Quiz #3 Ethernet (802.3), WLAN (802.11), LLC (802.2), bridges (802.1), VLANs (802.1Q), port access control (802.1X)
2019-03-22 Sheet #3 IPv6 forwarding in mininet, MTUs, fragmentation, and path MTUs (
2019-04-01 Quiz #4 IP forwarding, IPv6/ICMPv6, IPv4/ICMPv4
2019-04-12 Sheet #4 ospf and bgp (, common-bird.conf, f1-bird.conf)
2019-04-12 Quiz #5 Internet routing (rip, ospf, bgp)
2019-04-26 Sheet #5 TCP selective acknowledgments and trace analysis
2019-05-03 Quiz #6 TCP sequence numbers, acknowledgments, flags, flow control, congestion control
2019-05-10 Sheet #6 Domain name system (DNS), Multicast DNS, DNS Service Discovery
2019-05-27 Final Exam 12:30-14:30, SCC Hall 4 (closed book, handwritten single-sided a4 or double-sided a5 cheat sheet allowed)


The final grade is made up of the final exam (40%), biweekly quizzes (30%) and homework assignments (30%).

Electronic submission is the preferred way to hand in homework solutions. Please submit documents (plain ASCII/UTF-8 text or PDF, no Word) and your source code (packed into a tar or zip archive after removing all binaries and temporary files) via the online submission system. If you have problems, please contact one of the TAs.

Late submissions will not be accepted. Homeworks may need to be defended in an oral interview. In case you are ill, you have to follow the procedures defined in the university policies to obtain an official excuse. If you obtain an excuse, the new deadline will be calculated as follows:

  1. Determine the number of days you were excused until the deadline day, not counting excused weekend days.
  2. Determine the day of the end of your excuse and add the number of day you obtained in first step. This gives you the initial new deadline.
  3. If the period between the end of your excuse and the new deadline calculated in the second step includes weekend days, add them as well to the new deadline. (Iterate this step if necessary.)

For any questions stated on assignment sheets, quiz sheets, exam sheets or during makeups, we by default expect a reasoning for the answer given, unless explicitely stated otherwise.

Students must submit solutions individually. If you copy material verbatim from the Internet (or other sources), you have to provide a proper reference. If we find your solution text on the Internet without a proper reference, you risk to lose your points. Any cheating cases will be reported to the registrar. In addition, you will lose the points (of course).

Any programs, which have to be written, will be evaluated based on the following criteria:

  • correctness including proper handling of error conditions
  • proper use of programming language constructs
  • clarity of the program organization and design
  • readability of the source code and any output produced

Source code must be accompanied by a README file providing an overview of the source files and giving instructions how to build the programs. A suitable Makefile is required if the build process involves more than a single source file.

If you are unhappy with the grading, please report immediately (within one week) to the TAs. If you can't resolve things, contact the instructor. Problem reports which come late, that is after the one week period, are not considered anymore.

The policy on makeup quizzes is the following: There won't be any quiz makeups. If you (a) get an official excuse for a quiz from the registrar's office or (b) approach we well in advance of the quiz with a very good reason for not being able to participate (e.g., because you take a GRE computer science subject test at the day of a quiz), then the weight of the final exam will be increased according to the weight of the quiz you got excused for.