Inst. Telekommunikationssysteme

285 Items

Recent Submissions
EAGLE—A Scalable Query Processing Engine for Linked Sensor Data

Nguyen Mau Quoc, Hoan ; Serrano, Martin ; Mau Nguyen, Han ; G. Breslin, John ; Le-Phuoc, Danh (2019-10-09)

Recently, many approaches have been proposed to manage sensor data using semantic web technologies for effective heterogeneous data integration. However, our empirical observations revealed that these solutions primarily focused on semantic relationships and unfortunately paid less attention to spatio–temporal correlations. Most semantic approaches do not have spatio–temporal support. Some of t...

Virtual Network Embedding Approximations: Leveraging Randomized Rounding

Rost, Matthias ; Schmid, Stefan (2019-09-23)

The Virtual Network Embedding Problem (VNEP) captures the essence of many resource allocation problems. In the VNEP, customers request resources in the form of Virtual Networks. An embedding of a virtual network on a shared physical infrastructure is the joint mapping of (virtual) nodes to physical servers together with the mapping of (virtual) edges onto paths in the physical network connectin...

Supporting the Development of Cyber-Physical Systems with Natural Language Processing: A Report

Vogelsang, Andreas ; Hartig, Kerstin ; Pudlitz, Florian ; Schlutter, Aaron ; Winkler, Jonas (2019-03)

Software has become the driving force for innovations in any technical system that observes the environment with different sensors and influence it by controlling a number of actuators; nowadays called Cyber-Physical System (CPS). The development of such systems is inherently inter-disciplinary and often contains a number of independent subsystems. Due to this diversity, the majority of develop...

Requirements-based Simulation Execution for Virtual Validation of Autonomous Systems

Pudlitz, Florian (2019-03)

The complexity of software is rapidly increasing in many domains. Therefore, simulations have become established as a testing tool in recent years. Especially the virtual validation of autonomous systems leads to increasingly complex simulation environments. Nevertheless, the scenarios and the simulation results are not linked to the requirements. To close this gap, we develop a lightweight app...

Informed access network selection to improve application performance

Enghardt, Theresa (2019)

Adverse network conditions, such as long latency or low downstream capacity, may degrade application performance and lead to a bad Quality of Experience (QoE) for users, such as long Web page load times or interrupted video playback. As applications are highly diverse, connectivity via a single access network may not be able to satisfy all application needs. Since an end-user device often has m...

Simulation methods and tools for collaborative embedded systems: with focus on the automotive smart ecosystems

Cioroaica, Emilia ; Pudlitz, Florian ; Gerostathopoulos, Ilias ; Kuhn, Thomas (2019-11-20)

Embedded Systems are increasingly equipped with open interfaces that enable communication and collaboration with other embedded systems. Collaborative embedded systems (CES) can be seen as an emerging new class of systems which, although individually designed and developed, can form collaborations at runtime. When embedded systems collaborate with each other, functions developed independently n...

Extraction of System States from Natural Language Requirements

Pudlitz, Florian ; Brokhausen, Florian ; Vogelsang, Andreas (2019-12-05)

In recent years, simulations have proven to be an important means to verify the behavior of complex software systems. The different states of a system are monitored in the simulations and are compared against the requirements specification. So far, system states in natural language requirements cannot be automatically linked to signals from the simulation. However, the manual mapping between re...

Physical layer reliability aspects in industrial optical wireless communication

Wilke Berenguer, Pablo Rafael Andreas (2019)

In the past centuries, production processes have impressively evolved from mostly hand-made goods of small quantities to almost fully automated large scale productions. Three significant jumps are commonly referred to as industrial revolutions, which have brought first mechanization, then electrification, and in this century, partial automation to the production processes. The currently ongoing...

Towards Transiently Secure Updates in Asynchronous SDNs

Shukla, Apoorv ; Schütze, André ; Ludwig, Arne ; Dudycz, Szymon ; Schmid, Stefan ; Feldmann, Anja (2016-08)

Software-Defined Networks (SDNs) promise to overcome the often complex and error-prone operation of tradi- tional computer networks, by enabling programmabil- ity, automation and verifiability. Yet, SDNs also in- troduce new challenges, for example due to the asyn- chronous communication channel between the logically centralized control platform and the switches in the data plane. In particular...

Steering hyper-giants' traffic at scale

Pujol, Enric ; Poese, Ingmar ; Zerwas, Johannes ; Smaragdakis, Georgios ; Feldmann, Anja (2019-12-10)

Large content providers, known as hyper-giants, are responsible for sending the majority of the content traffic to consumers. These hyper-giants operate highly distributed infrastructures to cope with the ever-increasing demand for online content. To achieve 40 commercial-grade performance of Web applications, enhanced end-user experience, improved reliability, and scaled network capacity, hype...

Runtime Verification of P4 Switches with Reinforcement Learning

Shukla, Apoorv ; Hudemann, Kevin Nico ; Hecker, Artur ; Schmid, Stefan (2019-08-23)

We present the design and early implementation of p4rl, a system that uses reinforcement learning-guided fuzz testing to execute the verification of P4 switches automatically at runtime. p4rl system uses our novel user-friendly query language, p4q to conveniently specify the intended properties in simple conditional statements (if-else) and check the actual runtime behavior of the P4 switch aga...

Online Replication Strategies for Distributed Data Stores

Semmler, Niklas ; Smaragdakis, Georgios ; Feldmann, Anja (2019-08)

The rate at which data is produced at the network edge, e.g., collected from sensors and Internet of Things (IoT) devices, will soon exceed the storage and processing capabilities of a single system and the capacity of the network. Thus, data will need to be collected and preprocessed in distributed data stores—as part of a distributed database—at the network edge. Yet, even in this setup, the ...

Distributed Mega-Datasets: The Need for Novel Computing Primitives

Semmler, Niklas ; Smaragdakis, Georgios ; Feldmann, Anja (2019-07-07)

With the ongoing digitalization, an increasing number of sensors is becoming part of our digital infrastructure. These sensors produce highly, even globally, distributed data streams. The aggregate data rate of these streams far exceeds local storage and computing capabilities. Yet, for radical new services (e.g., predictive maintenance and autonomous driving), which depend on various control l...

BGP Communities: Even more Worms in the Routing Can

Streibelt, Florian ; Lichtblau, Franziska ; Beverly, Robert ; Feldmann, Anja ; Pelsser, Cristel ; Smaragdakis, Georgios ; Bush, Randy (2018-10-31)

BGP communities are a mechanism widely used by operators to manage policy, mitigate attacks, and engineer traffic; e.g., to drop unwanted traffic, filter announcements, adjust local preference, and prepend paths to influence peer selection. Unfortunately, we show that BGP communities can be exploited by remote parties to influence routing in unintended ways. The BGP community-based vulnerabilit...

Tracing Cross Border Web Tracking

Iordanou, Costas ; Smaragdakis, Georgios ; Poese, Ingmar ; Laoutaris, Nikolaos (2018-10-31)

A tracking flow is a flow between an end user and a Web tracking service. We develop an extensive measurement methodology for quantifying at scale the amount of tracking flows that cross data protection borders, be it national or international, such as the EU28 border within which the General Data Protection Regulation (GDPR) applies. Our methodology uses a browser extension to fully render ...

Stellar: Network Attack Mitigation using Advanced Blackholing

Dietzel, Christoph ; Wichtlhuber, Matthias ; Smaragdakis, Georgios ; Feldmann, Anja (2018-12-04)

Network attacks, including Distributed Denial-of-Service (DDoS), continuously increase in terms of bandwidth along with damage (recent attacks exceed 1.7 Tbps) and have a devastating impact on the targeted companies/governments. Over the years, mitigation techniques, ranging from blackholing to policy-based filtering at routers, and on to traffic scrubbing, have been added to the network opera...

Inferring BGP Blackholing Activity in the Internet

Giotsas, Vasileios ; Smaragdakis, Georgios ; Dietzel, Christoph ; Richter, Philipp ; Feldmann, Anja ; Berger, Arthur (2017-11-01)

The Border Gateway Protocol (BGP) has been used for decades as the de facto protocol to exchange reachability information among networks in the Internet. However, little is known about how this protocol is used to restrict reachability to selected destinations, e.g., that are under attack. While such a feature, BGP blackholing, has been available for some time, we lack a systematic study of its...

Detecting Peering Infrastructure Outages in the Wild

Giotsas, Vasileios ; Dietzel, Christoph ; Smaragdakis, Georgios ; Feldmann, Anja ; Berger, Arthur ; Aben, Emile (2017-08-20)

Peering infrastructures, namely, colocation facilities and Internet exchange points, are located in every major city, have hundreds of network members, and support hundreds of thousands of interconnections around the globe. These infrastructures are well provisioned and managed, but outages have to be expected, e.g., due to power failures, human errors, attacks, and natural disasters. However, ...

Flowtree: Enabling Distributed Flow Summarization at Scale

Saidi, Said Jawad ; Foucard, Damien ; Smaragdakis, Georgios ; Feldmann, Anja (2018-08-20)

NetFlow and IPFIX raw ow captures are insightful yet, due to their large volume, challenging to timely analyze and query. In particular, if these captures span long time periods or are collected at remote locations, storing or transferring them for analysis becomes increasingly expensive. Enabling efficient execution of a large range of queries over ow captures while reducing storage and tra...

Optimizing Gradual SDN Upgrades in ISP Networks

Poularakis, Konstantinos ; Iosifidis, George ; Smaragdakis, Georgios ; Tassiulas, Leandros (2019-01-11)

Nowadays, there is a fast-paced shift from legacy telecommunication systems to novel software-defined network (SDN) architectures that can support on-the-fly network reconfiguration, therefore, empowering advanced traffic engineering mechanisms. Despite this momentum, migration to SDN cannot be realized at once especially in high-end networks of Internet service providers (ISPs). It is expected...