TY - JOUR A1 - Wamser, Florian A1 - Seufert, Anika A1 - Hall, Andrew A1 - Wunderer, Stefan A1 - Hoßfeld, Tobias T1 - Valid statements by the crowd: statistical measures for precision in crowdsourced mobile measurements JF - Network N2 - Crowdsourced network measurements (CNMs) are becoming increasingly popular as they assess the performance of a mobile network from the end user's perspective on a large scale. Here, network measurements are performed directly on the end-users' devices, thus taking advantage of the real-world conditions end-users encounter. However, this type of uncontrolled measurement raises questions about its validity and reliability. The problem lies in the nature of this type of data collection. In CNMs, mobile network subscribers are involved to a large extent in the measurement process, and collect data themselves for the operator. The collection of data on user devices in arbitrary locations and at uncontrolled times requires means to ensure validity and reliability. To address this issue, our paper defines concepts and guidelines for analyzing the precision of CNMs; specifically, the number of measurements required to make valid statements. In addition to the formal definition of the aspect, we illustrate the problem and use an extensive sample data set to show possible assessment approaches. This data set consists of more than 20.4 million crowdsourced mobile measurements from across France, measured by a commercial data provider. KW - mobile networks KW - crowdsourced measurements KW - statistical validity Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-284154 SN - 2673-8732 VL - 1 IS - 2 SP - 215 EP - 232 ER - TY - RPRT A1 - Vomhoff, Viktoria A1 - Geißler, Stefan A1 - Hoßfeld, Tobias T1 - Identification of Signaling Patterns in Mobile IoT Signaling Traffic T2 - Würzburg Workshop on Next-Generation Communication Networks (WueWoWas'22) N2 - We attempt to identify sequences of signaling dialogs, to strengthen our understanding of the signaling behavior of IoT devices by examining a dataset containing over 270.000 distinct IoT devices whose signaling traffic has been observed over a 31-day period in a 2G network [4]. We propose a set of rules that allows the assembly of signaling dialogs into so-called sessions in order to identify common patterns and lay the foundation for future research in the areas of traffic modeling and anomaly detection. KW - Datennetz KW - IoT Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-280819 ER - TY - RPRT A1 - Vomhoff, Viktoria A1 - Geissler, Stefan A1 - Gebert, Steffen A1 - Hossfeld, Tobias T1 - Towards Understanding the Global IPX Network from an MVNO Perspective T2 - KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023 (WueWoWAS’23) N2 - In this paper, we work to understand the global IPX network from the perspective of an MVNO. In order to do this, we provide a brief description of the global architecture of mobile carriers. We provide initial results with respect to mapping the vast and complex interconnection network enabling global roaming from the point of view of a single MVNO. Finally, we provide preliminary results regarding the quality of service observed under global roaming conditions. KW - global IPX network Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-322121 ER - TY - BOOK A1 - Tran-Gia, Phuoc A1 - Hoßfeld, Tobias T1 - Performance Modeling and Analysis of Communication Networks BT - A Lecture Note N2 - This textbook provides an introduction to common methods of performance modeling and analysis of communication systems. These methods form the basis of traffic engineering, teletraffic theory, and analytical system dimensioning. The fundamentals of probability theory, stochastic processes, Markov processes, and embedded Markov chains are presented. Basic queueing models are described with applications in communication networks. Advanced methods are presented that have been frequently used in recent practice, especially discrete-time analysis algorithms, or which go beyond classical performance measures such as Quality of Experience or energy efficiency. Recent examples of modern communication networks include Software Defined Networking and the Internet of Things. Throughout the book, illustrative examples are used to provide practical experience in performance modeling and analysis. Target group: The book is aimed at students and scientists in computer science and technical computer science, operations research, electrical engineering and economics. N2 - Dieses Lehrbuch bietet eine Einführung in gängige Methoden zur Modellbildung und analytische Leistungsbewertung von Kommunikationssystemen. Diese Methoden bilden die Grundlage für Verkehrstheorie und Systemdimensionierung. Die Grundlagen der Wahrscheinlichkeitstheorie, stochastische Prozesse, Markov-Prozesse und eingebettete Markov-Ketten werden vorgestellt. Grundlegende Warteschlangenmodelle werden mit Anwendungen aus Kommunikationsnetzwerken beschrieben. Es werden auch weiterführende Methoden vorgestellt, die in der jüngeren Praxis häufig verwendet wurden, insbesondere zeitdiskrete Analysealgorithmen, oder QoE und Energieeffizienz. Aktuelle Beispiele für moderne Kommunikationsnetze sind Software Defined Networking oder das Internet der Dinge. Im gesamten Buch werden anschauliche Beispiele verwendet, um praktische Erfahrungen in der Leistungsmodellierung und -analyse zu vermitteln. Zielgruppe: Das Buch richtet sich an Studierende und WissenschaftlerInnen aus den Bereichen Informatik und technische Informatik, Operations Research, Elektrotechnik und Wirtschaftswissenschaft. KW - performance modeling KW - Markovian and Non-Markovian systems KW - discrete-time models and analysis KW - communication networks KW - communication network KW - performance evaluation KW - Markov model KW - stochastic processes KW - queueing theory Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-241920 SN - 978-3-95826-152-5 SN - 978-3-95826-153-2 N1 - Parallel erschienen als Druckausgabe in Würzburg University Press, 978-3-95826-152-5, 65,00 Euro. PB - Würzburg University Press CY - Würzburg ET - 1st edition ER - TY - JOUR A1 - Seufert, Anika A1 - Poignée, Fabian A1 - Seufert, Michael A1 - Hoßfeld, Tobias T1 - Share and multiply: modeling communication and generated traffic in private WhatsApp groups JF - IEEE Access N2 - Group-based communication is a highly popular communication paradigm, which is especially prominent in mobile instant messaging (MIM) applications, such as WhatsApp. Chat groups in MIM applications facilitate the sharing of various types of messages (e.g., text, voice, image, video) among a large number of participants. As each message has to be transmitted to every other member of the group, which multiplies the traffic, this has a massive impact on the underlying communication networks. However, most chat groups are private and network operators cannot obtain deep insights into MIM communication via network measurements due to end-to-end encryption. Thus, the generation of traffic is not well understood, given that it depends on sizes of communication groups, speed of communication, and exchanged message types. In this work, we provide a huge data set of 5,956 private WhatsApp chat histories, which contains over 76 million messages from more than 117,000 users. We describe and model the properties of chat groups and users, and the communication within these chat groups, which gives unprecedented insights into private MIM communication. In addition, we conduct exemplary measurements for the most popular message types, which empower the provided models to estimate the traffic over time in a chat group. KW - communication models KW - group-based communication KW - mobile instant messaging KW - mobile messaging application KW - private chat groups KW - WhatsApp Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-349430 VL - 11 ER - TY - JOUR A1 - Seufert, Anika A1 - Poignée, Fabian A1 - Hoßfeld, Tobias A1 - Seufert, Michael T1 - Pandemic in the digital age: analyzing WhatsApp communication behavior before, during, and after the COVID-19 lockdown JF - Humanities and Social Sciences Communications N2 - The strict restrictions introduced by the COVID-19 lockdowns, which started from March 2020, changed people’s daily lives and habits on many different levels. In this work, we investigate the impact of the lockdown on the communication behavior in the mobile instant messaging application WhatsApp. Our evaluations are based on a large dataset of 2577 private chat histories with 25,378,093 messages from 51,973 users. The analysis of the one-to-one and group conversations confirms that the lockdown severely altered the communication in WhatsApp chats compared to pre-pandemic time ranges. In particular, we observe short-term effects, which caused an increased message frequency in the first lockdown months and a shifted communication activity during the day in March and April 2020. Moreover, we also see long-term effects of the ongoing pandemic situation until February 2021, which indicate a change of communication behavior towards more regular messaging, as well as a persisting change in activity during the day. The results of our work show that even anonymized chat histories can tell us a lot about people’s behavior and especially behavioral changes during the COVID-19 pandemic and thus are of great relevance for behavioral researchers. Furthermore, looking at the pandemic from an Internet provider perspective, these insights can be used during the next pandemic, or if the current COVID-19 situation worsens, to adapt communication networks to the changed usage behavior early on and thus avoid network congestion. KW - cultural and media studies KW - information systems and information technology KW - science, technology and society Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-300261 VL - 9 ER - TY - CHAP A1 - Schlosser, Daniel A1 - Jarschel, Michael A1 - Duelli, Michael A1 - Hoßfeld, Tobias A1 - Hoffmann, Klaus A1 - Hoffmann, Marco A1 - Morper, Hans Jochen A1 - Jurca, Dan A1 - Khan, Ashiq T1 - A Use Case Driven Approach to Network Virtualization N2 - In today's Internet, services are very different in their requirements on the underlying transport network. In the future, this diversity will increase and it will be more difficult to accommodate all services in a single network. A possible approach to cope with this diversity within future networks is the introduction of support for running isolated networks for different services on top of a single shared physical substrate. This would also enable easy network management and ensure an economically sound operation. End-customers will readily adopt this approach as it enables new and innovative services without being expensive. In order to arrive at a concept that enables this kind of network, it needs to be designed around and constantly checked against realistic use cases. In this contribution, we present three use cases for future networks. We describe functional blocks of a virtual network architecture, which are necessary to support these use cases within the network. Furthermore, we discuss the interfaces needed between the functional blocks and consider standardization issues that arise in order to achieve a global consistent control and management structure of virtual networks. KW - Virtualisierung KW - Datenkommunikationsnetz KW - Internet KW - Rechnernetz KW - Anwendungsfall KW - Netzvirtualisierung KW - Standardisierung KW - Use case KW - network virtualization KW - future Internet architecture KW - standardization Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-55611 N1 - Accepted at IEEE Kaleidoscope 2010 ER - TY - RPRT A1 - Raffeck, Simon A1 - Geißler, Stefan A1 - Hoßfeld, Tobias T1 - Towards Understanding the Signaling Traffic in 5G Core Networks T2 - KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023 (WueWoWAS’23) N2 - The Fifth Generation (5G) communication technology, its infrastructure and architecture, though already deployed in campus and small scale networks, is still undergoing continuous changes and research. Especially, in the light of future large scale deployments and industrial use cases, a detailed analysis of the performance and utilization with regard to latency and service times constraints is crucial. To this end, a fine granular investigation of the Network Function (NF) based core system and the duration for all the tasks performed by these services is necessary. This work presents the first steps towards analyzing the signaling traffic in 5G core networks, and introduces a tool to automatically extract sequence diagrams and service times for NF tasks from traffic traces. KW - signaling traffic KW - 5G core network Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-322106 ER - TY - RPRT A1 - Raffeck, Simon A1 - Geißler, Stefan A1 - Hoßfeld, Tobias T1 - DBM: Decentralized Burst Mitigation for Self-Organizing LoRa Deployments T2 - Würzburg Workshop on Next-Generation Communication Networks (WueWoWas'22) N2 - This work proposes a novel approach to disperse dense transmission intervals and reduce bursty traffic patterns without the need for centralized control. Furthermore, by keeping the mechanism as close to the Long Range Wide Area Network (LoRaWAN) standard as possible the suggested mechanism can be deployed within existing networks and can even be co-deployed with other devices. KW - Datennetz KW - LoRa Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-280809 ER - TY - RPRT A1 - Nguyen, Kien A1 - Loh, Frank A1 - Hoßfeld, Tobias T1 - Challenges of Serverless Deployment in Edge-MEC-Cloud T2 - KuVS Fachgespräch - Würzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023 (WueWoWAS’23) N2 - The emerging serverless computing may meet Edge Cloud in a beneficial manner as the two offer flexibility and dynamicity in optimizing finite hardware resources. However, the lack of proper study of a joint platform leaves a gap in literature about consumption and performance of such integration. To this end, this paper identifies the key questions and proposes a methodology to answer them. KW - Edge-MEC-Cloud Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-322025 ER -