Communication Networks 1 / Kommunikationsnetze 1


Lecturer: Professor Frank Fitzek
Assistant: Dipl.-Ing. Stefan Senk
Assistant: Dipl.-Ing. Stefan Senk
Main lecturer



In this lecture the students will learn about the basic principles for communication systems. An important role has the layered communication protocol stack that allows for a global network with large flexibility. The different layers will be introduced and prominent protocols are discussed more in detail. Together with simple programming examples the students should understand the basic approach of communication networks. The lecture will also link the teaching content with ongoing research activities at the chair.

Course Basics

  • Language: German (slides/exercise tasks in English)
  • Course Number:
  • Compulsory course (ET/IT: 6th semester)
  • 2 2 0 (lecture/seminar/practical course)
  • Written exam: 150min

Corona related Information

  • All lectures and exercises will take place online as long as the situation requires it. We may update this information in future.
  • Please also follow official university advices.

Important Links

We request all students to enroll on the OPAL course and to join the TUD Matrix Chatroom. See links above.



Time Schedule Summer Semester 2021

  • Wednesday, 11:10 – 12:40
  • Thursday, 11:10 – 12:40

DateTypeLocationLinkTopicYoutube Videos
14.04.2021L0onlineOrganization, Introduction of ComNets ChairL0-01 to L0-02
15.04.2021L1onlineHistory and Introduction of Communication Systems/MotivationL1-01 to L1-03
21.04.2021L2onlineConcept of a layered model, 7 ISO/OSI model, StandardizationL2-01 to L2-06
22.04.2021E0+E1onlineE0: Introduction, E1: ISO-OSI Layer Model: Example tasks and protocols per layerE1
28.04.2021L3online[L1:PHY-1] Symbol and Bits, Different mediums, Error correction and detection on bitsL3-01 to L3-06
29.04.2021E2online[L1:PHY-1] Error detection with CRC and Hamming code; Error correction via GuessworkE2
05.05.2021Dies Academicus----
06.05.2021L4online[L2:DL-1] Channel Access, CSMA, CDMAL4-01 to L4-03
12.05.2021E3online[L2:DL-1] Throughput calculation of ALOHA, POLLING; Walsh code example (CDMA)E3
13.05.2021Ascension Day----
19.05.2021L5online[L2:DL-2] FEC and ARQ, IEEE802.3 Ethernet, Hub CommunicationL4-04 to L4-06
20.05.2021E4online[L2:DL-2] Sliding Window; ARQ; Collision Detection E4
02.06.2021L6online[L2:DL-3] IEEE802.11 WiFi, Throughput/LatencyL4-07 to L4-08
03.06.2021E5online[L2:DL-3] Cellular vs WiFi; ARQ with losses; Interframe spacing and throughput with WiFiE5
09.06.2021L7online[L3:N-1] Graph Theory: Max Flow Min Cut, Dijkstra, Mean Hop in Mesh Networks, Network Coding 101L5-01 to L5-05
10.06.2021E6online[L3:N-1] Topologies, Min-Cut/Ford-FulkersonE8
16.06.2021E7online[L3:N-1] Dijkstra, Multi-Hop/Mean Number of HopsE9
17.06.2021L8online[L3:N-2] Switching, IP Networking, Queuing TheoryL5-06 to L5-09
23.06.2021E8online[L3:N-2] Switching Technology; IP address calculation (IPv4, IPv6)E10
24.06.2021L9online[L4:T-1] UDP, TCP, Header, Variants, QUIC, Coded TCPL6-01 to L6-07
30.06.2021E9online[L4:T-1] TCP vs. UDP, Congestion Control, QUICE11
01.07.2021E10online[L5:N-1] Hands-on Session: We program a simple chat over TCP!-
07.07.2021L10online[L5-7:S,P,A-1] Higher Layer Protocols, RTP, SIP, Source Coding, Video CodecsL7-01
08.07.2021E11online[L5-7:S,P,A-1] Higher Layers: HTTP, TLS, Source Coding-
14.07.2021E12online[L5-7:S,P,A-1] BGP, Autonomous Systems; How does the internet work?-
15.07.2021L11onlineCross Layer and Header Compression; Overall aspects of ISO OSI reference model; Cellular SystemsL8-01, L9-01, L10-01
21.07.2021E13onlineCellular Systems-


Exam consultationonlineYour topics.-


Exam consultationBAR-If it absolutely necessary, you can contact Stefan or Paul via mail or Matrix chat and set up a meeting in person. You must submit your questions in advance! TUD hygiene concept must be followed.-

11:10 Uhr

Exam (150min)BAR/SCHÖ/E-Exam Announcement (PDF, German)
Hygiene Concept (PDF, German)
t.b.d.Exam reviewBAR I/15-Review your exam results. Contact Stefan or Paul via mail or Matrix chat and set up a meeting. TUD hygiene concept must be followed.-


  • L – Lecture
  • E – Exercise
  • t.b.d. – to be determined