Data Networks Ernst Moritz Hahn, Holger Hermanns



Feb 5-7: Delay-tolerant Satellite Networks (Mini Course)

Liebe Studierende,

for those still interested in networking:

we have Juan A. Fraire (U Cordoba/U Grenoble) visiting us next week.

He will present a mini course on

Routing, Congestion and Planning: Existing Solutions and... Read more

Liebe Studierende,

for those still interested in networking:

we have Juan A. Fraire (U Cordoba/U Grenoble) visiting us next week.

He will present a mini course on

Routing, Congestion and Planning: Existing Solutions and Persistent Challenges

in the form of three lectures, to take place on Mon/Tue/Wed 14:15-15:45 in E1 3, room 528 (we move to H003 in case of overflow).

Geostationary satellites allow to achieve continuous coverage throughout vast areas on ground at the expense of placing large spacecrafts at very high altitudes. Low-orbit satellites can overcome the latter issue, but many of them (possibly in the order of hundreds or even thousands) are required to provide similar footprint characteristics. In this context, Delay-Tolerant Satellite Networks (DTSNs) emerge from putting the stable and bidirectional connectivity assumption into perspective. Indeed, DTSNs can provide delay-tolerant services while leveraging smaller satellites (i.e., CubeSats) and innovative mission architectures and topologies. Specifically, end-to-end transactions are left aside for store-carry-forward transport which allows data to be temporarily kept in satellite storage until new links with ground or other satellites become available. Although a perfect fit for CCSDS and IETF Delay-Tolerant Networking protocols, several technological and research challenges are still to be met before launching large-scale and operative DTSNs. In this course, we introduce the concept of DTSNs as well as their attributes and possible applications, we overview the state-of-the art by revising experiments and implementations, analyze modeling alternatives and deepen in persistent challenges in the routing, congestion and planning domain.

Course Content:
• Overview of Satellite Networking
  General introduction to satellite communications and the challenge of building efficient and cost-effective satellite networks capable of interacting with the traditional Internet protocol suite on ground.
• Delay-Tolerant Satellite Networking (DTSN)
  Description of the Delay Tolerant Networking architecture and protocols, the state of the art, and their applicability on Delay-Tolerant Satellite Networking (DTSN), a new space-terrestrial networking paradigm.
• Routing in DTSNs
  In depth view on how the DTSN’s topology predictability can be modeled and used in feeding centralized or distributed routing algorithms to enhance overall data delivery ratio and delay.
• Congestion in DTSNs
  Analysis on existing techniques to mitigate the DTSN congestion problem, a new challenge in time-evolving and store-and-forward based networks involving not only link but storage capacity limitations.
• Planning in DTSNs
  Review on the planning aspect which can play a significant role in operationalizing real DTSNs in terms of interference avoidance, resource constraints, architectural limitations among others.

Juan A. Fraire received the Telecommunications Engineering degree at IUA in Córdoba, Argentina. In 2015, he obtained the PhD grade in Engineering and Applied Sciences from FCEFyN of the UNC as a member of the LCD laboratory. His main focus of research is the implementation and optimization of communication algorithms and protocol solutions for near-Earth and Interplanetary space networks. Although a young research path, Juan's work has been presented and recognized by international colleagues from JPL (NASA), European space agency (ESA), China National Space Administration (CNSA) and the Argentinian Space Agency (CONAE), and has derived in a full book on the topic as well as more than 35 leading journals and international conferences. Furthermore, since 2014, Juan is the chair of the annual Space-Terrestrial Internetworking (STINT) workshop, an international event for discussing the advances on space networking. Juan is an invited researcher at TIMA laboratories at Grenoble, France and has recently been awarded a CONICET associate researcher position in Argentina in cooperation with the Argentinian Space Agency (CONAE).

See you,
 H Hermanns


This module runs as a block course spanning September and early October 2017, prefixed by an individual home study period in August.

The course starts with a single introductory lecture on Friday, July 21 at 14:14 in HS 002 of E1 3.

Data Networks

This core course (Stammvorlesung) adresses Bachelor and Master students in Computer Science and related programs. It runs as a block course in September, prefixed by an individual home study phase in August. Bachelor students should have passed the base lectures Programmierung 1 and Programmierung 2. Some programming experience (e.g. in Python, C, Java, C# or JavaScript) is recommended. The language of the course is English. Due to resource constraints we may restrict participation to study programs for which this core course can indeed contribute.  


The course will explain data networks. Internet protocols will be used to motivate and explain basic concepts in data networks, as the Internet is today's data network par excellence. Hands-on experience will be gained in programming labs.

The course will roughly follow the book Computer Networking – A Top-Down Approach by James F. Kurose and Keith W. Ross (sixth edition). There will be reading assignments based on this book. While the library has a few copies available, we do recommend (groups of) students to obtain their own copy of this book.


The course starts with a single introductory lecture on Friday, July 21 at 14:14 in HS 002 of E1 3.

The main course work is scheduled to take place in the period from September 4 to October 13, 2017.

In September, there will usually be about two lectures (starting at 08:45 and 10:45) plus one tutorial (starting 13:30) per weekday. In addition there will be multiple programming labs and practical assignments. The language to be used in the programming labs will be mostly Python. Some knowledge of Unix/Linux is needed. August will be used as a home study period, especially to acquire knowledge in Python programming, and Unix/Linux.

An entrance exam on September 4 will check proficiency in Python, in Unix/Linux and in the general topic of the lecture (Chapter 1 of the textbook).

The preliminary course schedule is as follows. The contents indications are subject to change.

  • July 21: Introductory Lecture: Course organisation, topic overview, home study tasks
    September 4: Entrance exam
  • September 5
  • September 6: Recap of Chapter 1, Python and Linux/Unix
  • September 7: Application Layer (Chapter 2): principles of networking applications and  HTTP
  • September 8: Application Layer (Chapter 2): FTP, electronic mail, DNS

  • September 11: Transport Layer (Chapter 3): transport-layer services, multiplexing and demultiplexing, connectionless transport: UDP, principles of reliable data transfer
  • September 12: Transport Layer (Chapter 3): connection-oriented transport: TCP,  flow control, connection management, congestion control - Guest lecture on Modern Transport Layer Protocols by A. Schmidt
  • September 13: Network Layer (Chapter 4): virtual circuit and datagram networks, what’s inside a router, IP: Internet Protocol, datagram format, IPv4 addressing, ICMP, IPv6
    September 14: Network Layer (Chapter 4): routing algorithms, link state, distance vector
  • September 15: Network Layer (Chapter 4): hierarchical routing, routing in the Internet, RIP, OSPF, BGP, broadcast and multicast routing

  • September 18: Link Layer (Chapter 5): introduction, services, error detection, correction, multiple access protocols
  • September 19: Link Layer (Chapter 5): LANs, addressing, ARP, Ethernet, switches, VLANS, link virtualization: MPLS, data center networking, a day in the life of a web request
  • September 20: Wireless and Mobile Networks (Chapter 6): Wireless links, characteristics, CDMA, IEEE 802.11 wireless LANs (“Wi-Fi”)
  • September 21: Wireless and Mobile Networks (Chapter 6): Cellular Internet Access, architecture, standards (e.g., GSM), Mobility, Principles: addressing and routing to mobile users, Mobile IP, Handling mobility in cellular networks, Mobility and higher-layer protocols
  • September 22: Network Management (Chapter 9): What is network management?, Internet-standard management framework, Structure of Management Information: SMI, Management Information Base: MIB, SNMP Protocol Operations and Transport Mappings, Security and Administration, ASN.1
  • September 25: Guest lecture on Multimedia Networking by Prof. Herfet (Chapter 7)
  • September 26: Guest lecture on Network Security by Prof. Rossow (Chapter 8) 
  • September 27: Lecture wrap up
  • September 28
  • September 29: Project due date

  • October 6: Final exam
  • October 13: Latest project presentation date

If you encounter technical problems, please contact the administrators