Research

The CNDS research group is actively working on research projects, primarily in the computer networking domain. You can find a list of some of our research topics here. In case you are interested in any of our research areas, then please do not hesitate contact us for more details. Our research is often embedded into European research projects:

  • CONCORDIA (H2020, 2018-2022)
  • FLAMINGO (FP7, 2012-2016)
  • LEONE (FP7, 2012-2015)
  • EMANICS (FP6, 2006-2009)

Internet Management Technologies (2003-)

Members of the research group have more than 15 years of experience in the development, standardization, and implementation of Internet network management technologies. The recent focus has been on the following topics:

  • Definition of the YANG data modeling framework
  • Definition and testing of the NETCONF protocol
  • Development of high-level application programming interfaces
  • Automated translation of SMIv2 data models into YANG data models

Earlier work was been related to the SNMP protocol and its data modeling language SMI. For further information, see the following key publications:

  1. M. Björklund, J. Schönwälder, P. Shafer, K. Watsen, R. Wilton: Network Management Datastore Architecture (NMDA). RFC 8342, March 2018
  2. M. Badra, A. Luchuk, J. Schönwälder: Using the NETCONF Protocol over Transport Layer Security (TLS) with Mutual X.509 Authentication. RFC 7589, June 2015
  3. J. Schönwälder: Common YANG Data Types. RFC 6991, July 2013
  4. L. Andrey, O. Festor, A. Lahmadi, A. Pras, J. Schönwälder: Survey of SNMP Performance Analysis Studies. International Journal of Network Management 19(6), Wiley, November 2009
  5. J. Schönwälder: Translation of Structure of Management Information Version 2 (SMIv2) MIB Modules to YANG Modules. RFC 6643, July 2012
  6. R. Enns, M. Björklund, J. Schönwälder, A. Bierman: Network Configuration Protocol (NETCONF). RFC 6241, June 2011
  7. J. Schönwälder, M. Björklund, P. Shafer: Network Configuration Management using NETCONF and YANG. IEEE Communications Magazine 48(9), September 2010
  8. J. Schönwälder: Protocol-Independent Data Modeling: Lessons Learned from the SMIng Project. IEEE Communications Magazine 46(5):148-153, May 2008
  9. A. Pras, J. Schönwälder, M. Burgess, O. Festor, G. Martinez Perez, R. Stadler, B. Stiller: Key Research Challenges in Network Management. IEEE Communications Magazine 45(10), October 2007
  10. J. Schönwälder, A. Pras, J.-P. Martin-Flatin: On the Future of Internet Management Technologies. IEEE Communications Magazin, 41(10), October, 2003
  11. J. Schönwälder, J. Quittek, C. Kappler: Building Distributed Management Applications with the IETF Script MIB. IEEE Journal on Selected Areas in Communications, 18(5), May 2000

Large-scale Internet Measurements (2012-)

Large-scale measurement platforms such as RIPE Atlas or Sam Knows have been developed in order to measure the performance of the Internet from a wide variety of endpoints. A key goal is to estimate the service quality delivered to customers and to identify problems impacting the service quality. In the context of large scale Internet measurements, we have been working on the following topics:

  • Standardization of measurement control protocols (LMAP)
  • Measurement of the impact of the transition to IPv6
  • Measurement of access network (last-mile) characteristics

For further information, see the following key publications:

  1. J. Schönwälder, V. Bajpai: A YANG Data Model for LMAP Measurement Agents. RFC 8194, August 2017
  2. T. Burbridge, P. Eardley, M. Bagnulo, J. Schönwälder: Information Model for Large-Scale Measurement Platforms (LMAPs). RFC 8193, August 2017
  3. V. Bajpai, S. Ahsan, J. Schönwälder, J. Ott: Measuring YouTube over IPv6. ACM SIGCOMM Computer Communication Review 47(5), October 2017
  4. V. Bajpai, S.J. Eravuchira, J. Schönwälder: Dissecting Last-mile Latency Characteristics. ACM SIGCOMM Computer Communication Review 47(5), October 2017
  5. V. Bajpai, J. Schönwälder: Understanding the Impact of Network Infrastructure Changes using Large-Scale Measurement Platforms. 15th IFIP/IEEE International Symposium on Integrated Network Management (IM 2017), May 2017
  6. S.J. Eravuchira, V. Bajpai, J. Schönwälder, S. Crawford: Measuring Web Similarity from Dual-stacked Hosts. 12th International Conference on Network and Service Management (CNSM 2016), October 2016
  7. V. Bajpai, J. Schönwälder: A Survey on Internet Performance Measurement Platforms and Related Standardization Efforts IEEE Communications Surveys and Tutorials 17(3), August 2015

Flow-based Network Traffic Analysis (2007-2017)

We are interested in understanding how real-world networks behave. Since packet inspection does not scale, we are primarily looking into the analysis of aggregated traffic flows. We are working both on base technology for processing large amounts of flow records and its application for identifying applications and users based on their specific flow signatures. Our work has covered the following topics:

  • Cybermetrics – user identification based on flow records
  • Detection of application signatures in flow records
  • Stream-based flow query processing
  • Trace animation and visualization

For further information, see the following key publications:

  1. V. Bajpai, J. Schönwälder: Network Flow Query Language – Design, Implementation, Performance and Applications. IEEE Transactions on Network and Service Management 14(1), March 2017
  2. V. Perelman, N. Melnikov, J. Schönwälder: Flow Signatures of Popular Applications. 12th IFIP/IEEE International Symposium on Integrated Network Management, May 2011
  3. N. Melnikov, J. Schönwälder: Cybermetrics: User Identification Through Network Flow Analysis. 4th Conference on Autonomous Infrastructure, Management and Security (AIMS 2010), Springer LNCS 6155, June 2010
  4. P. Dobrev, S. Stancu-Mara, J. Schönwälder: Visualization of Node Interaction Dynamics in Network Traces. 3rd Conference on Autonomous Infrastructure, Management and Security (AIMS 2009), Springer LNCS 5637, June 2009
  5. J. Schönwälder, A. Pras, M. Harvan, J. Schippers, R. van de Meent: SNMP Traffic Analysis: Approaches, Tools, and First Results. 10th IFIP/IEEE International Symposium on Integrated Network Management (IM 2007), May 2007

Protocols for the Internet of Things (2008-2016)

The Internet is streching out into everyday objects. There is a large potential in networking everyday things and some people even believe that smart objects are helping to solve our energy consumption problems (by enabling smart power grids). In the context of the Internet of Things, we have been working on the following topics:

  • 6LoWPAN implementation and interoperability testing
  • SNMP on constrained devices
  • NETCONF on constrained devices
  • Evaluation of attacks on the RPL routing protocol
  • Development of MIB modules for 6LoWPAN and RPL

For further information, see the following key publications:

  1. M. Ersue, D. Romascanu, J. Schönwälder, A. Sehgal: Management of Networks with Constrained Devices: Use Cases. RFC 7548, May 2015
  2. M. Ersue, D. Romascanu, J. Schönwälder, U. Herberg: Management of Networks with Constrained Devices: Problem Statement and Requirements. RFC 7547, May 2015
  3. A. Mayzaud, A. Sehgal, R. Badonnel, I. Chrisment, J. Schönwälder: Mitigation of Topological Inconsistency Attacks in RPL-based Low Power Lossy Networks. International Journal of Network Management 25(5), Wiley, September 2015
  4. J. Schönwälder, A. Sehgal, T. Tsou, C. Zhou: Definition of Managed Objects for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs). RFC 7388, October 2014
  5. A. Mayzaud, A. Sehgal, R. Badonnel, I. Chrisment, J. Schönwälder: A Study of RPL DODAG Version Attacks. 8th International Conference on Autonomous Infrastructure, Management and Security (AIMS 2014), June-July 2014
  6. A. Sehgal, V. Perelman, S. Kuryla, J. Schönwälder: Management of Resource Constrained Devices in the Internet of Things. IEEE Communications Magazine 50(12), December 2012
  7. K.D. Korte, I. Tumar, J. Schönwälder: Evaluation of IPv6 over Low-Power Wireless Personal Area Networks Implementations. 4th IEEE International Workshop on Practical Issues in Building Sensor Network Applications (SenseApp 2009), October 2009

Network Protocol Security (2006-2011)

The Internet developed from a research network into a basic utility of today’s society and the global economy. While in the early days security did not play a major role in the design of protocols, the state of things has changed completely. While the use of cryptographic algorithms to protect protocols is meanwhile reasonably well understood, the biggest problem remains the interface to humans (in particular key management schemes) but also the performance impact of security protocols must be understood. In this context, we have been working on the following topics:

  • Design of a session resumption mechanism for SSH
  • Extensions of the SNMP architecture to leverage secure transports
  • Performance analysis of SNMP over SSH/TLS/DTLS
  • Prefix- and lexicographic-order-preserving IP address anonymization

For further information, see the following key publications:

  1. J. Schönwälder, V. Marinov: On the Impact of Security Protocols on the Performance of SNMP. IEEE Transactions on Network and Service Management 8(1), April 2011
  2. J. Schönwälder, G. Chulkov, E. Asgarov, M. Cretu: Session Resumption for the Secure Shell Protocol. 11th IFIP/IEEE International Symposium on Integrated Network Management (IM 2009), June 2009
  3. M. Harvan, J. Schönwälder: Prefix- and Lexicographical-order-preserving IP Address Anonymization. 10th IEEE/IFIP Network Operations and Management Symposium, April 2006
  4. D. Harrington, J. Schönwälder: Transport Subsystem for the Simple Network Management Protocol (SNMP). RFC 5590, June 2009
  5. A. Kehne, J. Schönwälder, H. Langendörfer: A Nonce-Based Protocol for Multiple Authentications. Operating System Review, 26(4), October 1992

Underwater Networks (2009-2011)

Underwater networking technologies are recently getting more research attention since the exploration and monitoring of the oceans has become increasingly important. In the aquatic environment, acoustic communication is frequently used to cover longer distances since higher frequencies are easily absorbed. Furthermore, the characteristics of the acoustic channel change significantly depending on the depth, salinity, or temperature of the water, and there are often strong fluctuations of the channel characteristics. We have been working on the following topics:

  • Channel, propagation and ambient noise models
  • NS-2 based underwater networking simulation
  • USARSim based underwater robotics communication simulation
  • Environmentally adaptive networking (routing, modulation)

For further information, see the following publications:

  1. A. Sehgal, C. David, J. Schönwälder: Energy Consumption Analysis of Underwater Acoustic Sensor Networks. MTS/IEEE Oceans 2011, September 2011
  2. A. Sehgal, I. Tumar, J. Schönwälder: AquaTools: An Underwater Acoustic Networking Simulation Toolkit. IEEE Oceans, May 2010
  3. A. Sehgal, I. Tumar, J. Schönwälder: Effects of Climate Change and Anthropogenic Ocean Acidification on Underwater Acoustic Communications. IEEE Oceans, May 2010
  4. I. Tumar, A. Sehgal, J. Schönwälder: Power Management for Acoustic Underwater Networks. 6th IEEE Conference on Sensor, Mesh and Ad Hoc Communications and Networks (SECON 2009), June 2009
  5. A. Sehgal, I. Tumar, J. Schönwälder: Variability of Available Capacity due to the Effects of Depth and Temperature in the Underwater Acoustic Communication Channel. IEEE OCEANS 2009, May 2009

Disruption Tolerant Networks (2008-2011)

Disruption tolerant networks are designed to provide communication in unstable and stressed environments, where the network is subject to frequent and long lasting disruptions. In this context, we have looked at techniques that can save energy and at the same time offer a high probability to enable communication.

For further information, see the following key publications:

  1. I. Tumar, A. Sehgal, J. Schönwälder: Impact of Mobility Patterns on the Performance of a Disruption Tolerant Network with Multi-Radio Energy Conservation. 25th International Conference on Advanced Information Networking and Applications (AINA-2011), March 2011
  2. I. Tumar, A. Sehgal, J. Schönwälder: Performance Evaluation of a Multi-Radio Energy Conservation Scheme for Disruption Tolerant Networks. 8th ACM International Symposium on Mobility Management and Wireless Access (MobiWac 2010), October 2010

Distributed Case-based Reasoning (2007-2011)

The resolution of faults in communication networks and distributed systems is to a large extend a human driven process. The fault resolution process is usually assisted by trouble ticket systems to organize the work-flows. Today, the Internet contains a large amount of information that can be used to find similar cases in order to resolve a fault. However, general purpose search engines do not work too well. Our contribution is the design of a distributed case-based reasoning system to assist operators in resolving faults:

  • Peer-to-peer architecture using feedback search
  • Semi-structured multi-vector data representation method
  • Crawlers for extracting data from bug tracking systems
  • Probabilisitic and collaborative reasoning engines

For further information, see the following key publications:

  1. H.M. Tran, J. Schönwälder: DisCaRia – Distributed Case-based Reasoning System for Fault Management. IEEE Transactions on Network and Service Management 12(4), December 2015
  2. H.M. Tran, C. Lange, G. Chulkov, J. Schönwälder, M. Kohlhase: Applying Semantic Techniques to Search and Analyze Bug Tracking Data. Journal of Network and Systems Management 17(3), Springer, September 2009