Steffen Gebert's research while affiliated with University of Wuerzburg and other places

Publications (27)

Article
Full-text available
SDN and NFV gained significant momentum within the last years. Although widely used in research labs and cloud environments, SDN has not yet been deployed in mobile telecommunication networks. In this paper, we focus on use cases driving mobile network evolution towards cost-efficient IT-based solutions using standardized hardware and software-base...
Article
The softwarization of networks promises cost savings and better scalability of network functions by moving functionality from specialized devices into commercial off-the-shelf hardware. Generalized computing hardware offers many degrees of adjustment and tuning, which can affect performance and resource utilization. One of these adjustments are int...
Article
In recent years, the number of attacks and threat vectors against enterprise networks have been constantly increasing in numbers and variety. Despite these attacks, the main security systems, for example network firewalls, have remained rather unchanged. In addition, new challenges arise not only to the level of provided security, but also to the s...
Conference Paper
Network Functions Visualization (NFV) replaces physical middleboxes with software instances running network functions in cloud environments. To support this new paradigm, it is necessary to port the code basis from highly specialized hardware devices to virtual machines running on COTS hardware. In order to fully exploit the inherent capabilities o...
Conference Paper
The network functions virtualization (NFV) paradigm promises higher flexibility, vendor-independence, and higher cost-efficiency for network operators. Its key concept consists of virtualizing the functions of specialized hardware-based middleboxes like load balancers or firewalls and running them on commercial off-the-shelf (COTS) hardware. This w...
Conference Paper
SDN introduces the separation of network control and network data plane. The control plane is removed from distributed network entities and logically centralized as the SDN controller. To provide resilience and performance such a logically centralized controller may again be physically distributed. Scenarios featuring distributed controller archite...
Conference Paper
This work demonstrates TableVisor, a proxy layer for the OpenFlow control channel, which emulates a multi-table switch towards the controller. TableVisor uses one single-table switch per emulated flow table and combines all devices with their specific capabilities to a feature-rich pipeline consisting of multiple tables. As the used switches can be...
Conference Paper
The Software Defined Networking~(SDN) concept introduces a paradigm shift in the networking world towards an externalized control plane which is logically centralized. When designing an SDN-based WAN architecture, it is of vital importance to find a feasible solution to the controller placement problem, i.e., to decide where to position a limited a...
Article
Software Defined Networking (SDN) introduces the concept of logically-centralized controllers in charge of managing the forwarding behavior of network elements. The new possibilities enabled through the centralization of control logic come with a certain risk: The controller might become a performance bottleneck. Therefore, ensuring sufficient cont...
Article
Software Defined Networking (SDN) marks a paradigm shift towards an externalized and logically centralized network control plane. A particularly important task in SDN architectures is that of controller placement, i.e., the positioning of a limited number of resources within a network to meet various requirements. These requirements range from late...
Conference Paper
Performance isolation between virtual resources is one of the key features of network virtualization. It is typically realized by configuring queues with specific rate guarantees on the egress ports of network devices. The drawback of this architectural choice, however, is that traffic from several ingress ports may result in congestion on an egres...
Conference Paper
This paper investigates the influence of the network planning process on a higher energy-awareness of optical multi-layer core networks. In particular, we propose to remove redundant links in the network, and to route corresponding network traffic on other links. Based on the reduced network topology, we compute the required network equipment for r...
Conference Paper
Recently, Software Defined Networking (SDN) has gained a lot of attention. The paradigm shift towards centralized architectures with a separation of control plane and data plane is expected for several use cases, including amongst others core communication networks, data center networks, or Network Function Virtualization (NFV). An important issue...
Conference Paper
With the introduction of Software Defined Networking (SDN), the concept of an external and optionally centralized network control plane, i.e. controller, is drawing the attention of researchers and industry. A particularly important task in the SDN context is the placement of such external resources in the network. In this paper, we discuss importa...
Conference Paper
The fast changing application types and their behavior require consecutive measurements of access networks. In this paper, we present the results of a 14-day measurement in an access network connecting 600 users with the Internet. Our application classification reveals a trend back to HTTP traffic, underlines the immense usage of flash videos, and...

Citations

... Performance Monitoring [18] Performance Modeling [1,2,19] Control Plane Performance [10,14] Traffic Modeling [6,17,22,23] Network Security [15] Data Plane Abstraction [3,12,20] Methodology [21] Simulative Performance Analysis [4] Performance Modeling. Subsequently, in Chapter 2 of this thesis, we apply our monitoring approach to obtain measurement values for a state-of-the-art software router. ...
... The network enablers including Software-Defined Networking (SDN), Network Function Virtualization (NFV), Mobile Edge Computing (MEC) can play an important role in the QoE-aware network management [14], [217]- [219]. The QoE management in 6G and beyond networks using network enabling technologies promises network programmability, scalability, agility, distributive computing, dynamic resource optimization and automation which will allow nextgeneration networks to fulfil the user-perceived quality for emerging video streaming applications while being costeffective [12], [215], [220], [221]. The QoE management of the softwarized and virtualized next-generation networks requires the deployment of QoE monitoring and measurement solution on top of SDN controller/NFV Management and Orchestration (MANO) [222]- [225]. ...
... The diversity as presented in this paper can handle both stateless and stateful VNFs. Though, without loss of generality, stateful feature is more complex to achieve since it requires using a shared volume to save pool states [17] and to maintain continuous synchronization. This volume needs to be duplicated to maintain replicas states. ...
... We highlight that some tools exist [18] to monitor and plan the resource allocation of VNFs, but they need to be integrated within the tenants' sequence of VNFs, and therefore are opaque to the server owner. With our approach, the server owner would have the possibility to analyze the requirements for a plethora of use-cases and plan the resources accordingly [38]. Moreover, a simple algorithm that periodically analyzes the CPU fingerprint can, at runtime, adjust the resource allocation accordingly, without any change on the tenants' or the operator's side, or quickly associate special patterns to misbehavior. ...
... Nowadays most studies related to virtualized networks and service chains become aware of handling the requested virtual service network while satisfying various types of pre-defined policies [29,30]. These policies could be about placement such as affinity and/or anti-affinity policies [27], security [31,32], cost and eco-efficiency [33], or policies that consider revenue maximization and Quality of Service (QoS) [34]. Therefore, validating these policies before mapping and allocating the requested virtual network service is a must [27,35]. ...
... Similarly, performance aspects need to be taken into consideration when migrating from dedicated hardware to VNFs on COTS servers or deciding between different implementations of the same network function. On the one hand, we demonstrate the performance gap in terms of the processing time and maximum capacity between a dedicated firewall middlebox and a software-based implementation in [10]. On the other hand, we illustrate that while the use of acceleration techniques can significantly improve the packet processing performance of VNFs, it might also reveal new bottlenecks that need to be addressed to maximize the overall throughput [9]. ...
... While a recent work [11] also takes into account spine information for SDN networks, our proposal is not to design reliable SDN networks containing spines, but rather to allow evaluation of their characteristics. The usage of discrete-event simulation in SDN is common, particularly to evaluate the performance of particular protocols or network architectures [5]. However, reliability studies frequently use it in the context of Monte-Carlo methods [4], unlike in the discrete-event simulation used in this work. ...
... Models in the context of NFV have also recently appeared [68][69][70][71][72]. In particular, queuing models are used in [68] and [69] to describe software-based networks. ...
... 6 The implementation of this use case can be found in the GitHub repository accompanying this work. 7 Note that the P4 device in this scenario could also be replaced by a VNF performing the processing tasks. This again simplifies rapid prototyping and seamless integration of complex networking functionality without modification of the control plane in a brownfield deployment. ...
... Additionally, the softwarization of networks is often accompanied by the application of software development paradigms during network function development. Especially in the area of continuous integration and delivery, the availability of fast, reliable, and automatable mechanisms to obtain comparable performance metrics of a new version of a network application is required [96]. ...