@techreport{SertbasBuelbuelErgencFischer2022,
  type      = {Working Paper},
  author    = {Sertbas B{\"u}lb{\"u}l, Nurefsan and Ergenc, Doganalp and Fischer, Mathias},
  title     = {Evaluating Dynamic Path Reconfiguration for Time Sensitive Networks},
  series = {W{\"u}rzburg Workshop on Next-Generation Communication Networks (WueWoWas'22)},
  journal   = {W{\"u}rzburg Workshop on Next-Generation Communication Networks (WueWoWas'22)},
  doi       = {10.25972/OPUS-28074},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-280743},
  pages     = {5},
  year      = {2022},
  abstract  = {In time-sensitive networks (TSN) based on 802.1Qbv, i.e., the time-aware Shaper (TAS) protocol, precise transmission schedules and, paths are used to ensure end-to-end deterministic communication. Such resource reservations for data flows are usually established at the startup time of an application and remain untouched until the flow ends. There is no way to migrate existing flows easily to alternative paths without inducing additional delay or wasting resources. Therefore, some of the new flows cannot be embedded due to capacity limitations on certain links which leads to sub-optimal flow assignment. As future networks will need to support a large number of lowlatency flows, accommodating new flows at runtime and adapting existing flows accordingly becomes a challenging problem. In this extended abstract we summarize a previously published paper of us [1]. We combine software-defined networking (SDN), which provides better control of network flows, with TSN to be able to seamlessly migrate time-sensitive flows. For that, we formulate an optimization problem and propose different dynamic path configuration strategies under deterministic communication requirements. Our simulation results indicate that regularly reconfiguring the flow assignments can improve the latency of time-sensitive flows and can increase the number of flows embedded in the network around 4\% in worst-case scenarios while still satisfying individual flow deadlines.},
  subject      = {Datennetz},
  language  = {en}
}
@techreport{DworzakGrossmannLe2023,
  type      = {Working Paper},
  author    = {Dworzak, Manuel and Großmann, Marcel and Le, Duy Thanh},
  title     = {Federated Learning for Service Placement in Fog and Edge Computing},
  series = {KuVS Fachgespr{\"a}ch - W{\"u}rzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023 (WueWoWAS'23)},
  journal   = {KuVS Fachgespr{\"a}ch - W{\"u}rzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023 (WueWoWAS'23)},
  doi       = {10.25972/OPUS-32219},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-322193},
  pages     = {4},
  year      = {2023},
  abstract  = {Service orchestration requires enormous attention and is a struggle nowadays. Of course, virtualization provides a base level of abstraction for services to be deployable on a lot of infrastructures. With container virtualization, the trend to migrate applications to a micro-services level in order to be executable in Fog and Edge Computing environments increases manageability and maintenance efforts rapidly. Similarly, network virtualization adds effort to calibrate IP flows for Software-Defined Networks and eventually route it by means of Network Function Virtualization. Nevertheless, there are concepts like MAPE-K to support micro-service distribution in next-generation cloud and network environments. We want to explore, how a service distribution can be improved by adopting machine learning concepts for infrastructure or service changes. Therefore, we show how federated machine learning is integrated into a cloud-to-fog-continuum without burdening single nodes.},
  language  = {en}
}
@techreport{SimonGallenmuellerCarle2023,
  type      = {Working Paper},
  author    = {Simon, Manuel and Gallenm{\"u}ller, Sebastian and Carle, Georg},
  title     = {Never Miss Twice - Add-On-Miss Table Updates in Software Data Planes},
  series = {KuVS Fachgespr{\"a}ch - W{\"u}rzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023 (WueWoWAS'23)},
  journal   = {KuVS Fachgespr{\"a}ch - W{\"u}rzburg Workshop on Modeling, Analysis and Simulation of Next-Generation Communication Networks 2023 (WueWoWAS'23)},
  doi       = {10.25972/OPUS-32207},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-322071},
  pages     = {5},
  year      = {2023},
  abstract  = {State Management at line rate is crucial for critical applications in next-generation networks. P4 is a language used in software-defined networking to program the data plane. The data plane can profit in many circumstances when it is allowed to manage its state without any detour over a controller. This work is based on a previous study by investigating the potential and performance of add-on-miss insertions of state by the data plane. The state keeping capabilities of P4 are limited regarding the amount of data and the update frequency. We follow the tentative specification of an upcoming portable-NIC-architecture and implement these changes into the software P4 target T4P4S. We show that insertions are possible with only a slight overhead compared to lookups and evaluate the influence of the rate of insertions on their latency.},
  language  = {en}
}
@phdthesis{NguyenNgoc2018,
  author    = {Nguyen-Ngoc, Anh},
  title     = {On Performance Assessment of Control Mechanisms and Virtual Components in SDN-based Networks},
  issn      = {1432-8801},
  doi       = {10.25972/OPUS-16932},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169328},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2018},
  abstract  = {This dissertation focuses on the performance evaluation of all components of Software Defined Networking (SDN) networks and covers whole their architecture. First, the isolation between virtual networks sharing the same physical resources is investigated with SDN switches of several vendors. Then, influence factors on the isolation are identified and evaluated. Second, the impact of control mechanisms on the performance of the data plane is examined through the flow rule installation time of SDN switches with different controllers. It is shown that both hardware-specific and controller instance have a specific influence on the installation time. Finally, several traffic flow monitoring methods of an SDN controller are investigated and a new monitoring approach is developed and evaluated. It is confirmed that the proposed method allows monitoring of particular flows as well as consumes fewer resources than the standard approach. Based on findings in this thesis, on the one hand, controller developers can refer to the work related to the control plane, such as flow monitoring or flow rule installation, to improve the performance of their applications. On the other hand, network administrators can apply the presented methods to select a suitable combination of controller and switches in their SDN networks, based on their performance requirements},
  subject      = {Leistungsbewertung},
  language  = {en}
}
@techreport{SavvidisRothTutsch2022,
  type      = {Working Paper},
  author    = {Savvidis, Dimitrios and Roth, Robert and Tutsch, Dietmar},
  title     = {Static Evaluation of a Wheel-Topology for an SDN-based Network Usecase},
  series = {W{\"u}rzburg Workshop on Next-Generation Communication Networks (WueWoWas'22)},
  journal   = {W{\"u}rzburg Workshop on Next-Generation Communication Networks (WueWoWas'22)},
  doi       = {10.25972/OPUS-28071},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-280715},
  pages     = {3},
  year      = {2022},
  abstract  = {The increased occurrence of Software-Defined-Networking (SDN) not only improves the dynamics and maintenance of network architectures, but also opens up new use cases and application possibilities. Based on these observations, we propose a new network topology consisting of a star and a ring topology. This hybrid topology will be called wheel topology in this paper. We have considered the static characteristics of the wheel topology and compare them with known other topologies.},
  subject      = {Datennetz},
  language  = {en}
}
@techreport{BlenkKellererHossfeld2020,
  type      = {Working Paper},
  author    = {Blenk, Andreas and Kellerer, Wolfgang and Hoßfeld, Tobias},
  title     = {Technical Report on DFG Project SDN-App: SDN-enabled Application-aware Network Control Architectures and their Performance Assessment},
  doi       = {10.25972/OPUS-20755},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-207558},
  year      = {2020},
  abstract  = {The DFG project "SDN-enabled Application-aware Network Control Architectures and their Performance Assessment" (DFG SDN-App) focused in phase 1 (Jan 2017 - Dec 2019) on software defined networking (SDN). Being a fundamental paradigm shift, SDN enables a remote control of networking devices made by different vendors from a logically centralized controller. In principle, this enables a more dynamic and flexible management of network resources compared to the traditional legacy networks. Phase 1 focused on multimedia applications and their users' Quality of Experience (QoE). This documents reports the achievements of the first phase (Jan 2017 - Dec 2019), which is jointly carried out by the Technical University of Munich, Technical University of Berlin, and University of W{\"u}rzburg. The project started at the institutions in Munich and W{\"u}rzburg in January 2017 and lasted until December 2019. In Phase 1, the project targeted the development of fundamental control mechanisms for network-aware application control and application-aware network control in Software Defined Networks (SDN) so to enhance the user perceived quality (QoE). The idea is to leverage the QoE from multiple applications as control input parameter for application-and network control mechanisms. These mechanisms are implemented by an Application Control Plane (ACP) and a Network Control Plane (NCP). In order to obtain a global view of the current system state, applications and network parameters are monitored and communicated to the respective control plane interface. Network and application information and their demands are exchanged between the control planes so to derive appropriate control actions. To this end, a methodology is developed to assess the application performance and in particular the QoE. This requires an appropriate QoE modeling of the applications considered in the project as well as metrics like QoE fairness to be utilized within QoE management. In summary, the application-network interaction can improve the QoE for multi-application scenarios. This is ensured by utilizing information from the application layer, which are mapped by appropriate QoS-QoE models to QoE within a network control plane. On the other hand, network information is monitored and communicated to the application control plane. Network and application information and their demands are exchanged between the control planes so to derive appropriate control actions.},
  subject      = {Software-defined networking},
  language  = {en}
}