Thomas Zinner

Norwegian University of Science and Technology | NTNU · Department of Information Security and Communication Technology

Network softwarization is one of the key enablers of the future Internet evolution, also supporting the road from the fifth generation (5G) to the next-generation communication systems, namely 6G, with their main objective of bringing hyper-connected experience to every corner of society.

Monitoring and providing customers with a satisfying Quality of Experience (QoE) is a crucial business incentive for mobile network operators (MNOs). While the MNO is capable of monitoring a vast amount of network-related key performance indicators (KPIs), it typically does not have access to application-specific performance metrics. Among others,...

div>The visions of 5G and beyond (B5G) imply unprecedented expectations toward general digital high-performing connectivity services in both public and private networks. Connectivity services that offer performance guarantees along multiple QoS dimensions are partially available today, but are confined to (virtual) private network services. However...

div>The visions of 5G and beyond (B5G) imply unprecedented expectations toward general digital high-performing connectivity services in both public and private networks. Connectivity services that offer performance guarantees along multiple QoS dimensions are partially available today, but are confined to (virtual) private network services. However...

To support heterogeneous network services with strict requirements for various performance characteristics, 5G networks leverage network softwarization and virtualization paradigms such as software defined networking (SDN), network functions virtualization (NFV), and network slicing. The resulting architecture features a high degree of complexity w...

Network Functions Virtualization (NFV) is among the latest network revolutions, promising increased flexibility and avoiding network ossification. At the same time, all-software NFV implementations on commodity hardware raise performance issues when comparing to ASIC solutions. To address these issues, numerous software acceleration frameworks for...

The hierarchical token bucket (HTB) algorithm allows to specify per-flow bitrate guarantees and enables excess bandwidth sharing between flows of the same class. Additionally, it provides capabilities to prioritize the traffic of specific flows, potentially considering their delay demands. HTB hence constitutes a powerful mechanism to enforce QoS r...

The Softwarization of networks is enabled by the SDN (Software-Defined Networking), NV (Network Virtualization), and NFV (Network Function Virtualization) paradigms, and offers many advantages for network operators, service providers and data-center providers. Given the strong interest in both industry and academia in the softwarization of telecomm...

Providing scalable user- and application-aware resource allocation for heterogeneous applications sharing an enterprise network is still an unresolved problem. The main challenges are as follows: (i) How do we define user- and application-aware shares of resources? (ii) How do we determine an allocation of shares of network resources to application...

The prevailing wisdom is that a software-defined network (SDN) operates under the premise that the logically centralized control plane has an accurate representation of the actual data plane state. Unfortunately, bugs, misconfigurations, faults or attacks can introduce inconsistencies between the network control and the data plane that can undermin...

The softwarization of networks is enabled by the SDN (Software-Defined Networking), NV (Network Virtualization), and NFV (Network Function Virtualization) paradigms, and offers many advantages for network operators, service providers and datacenter providers. Given the strong interest in both industry and academia in the softwarization of telecommu...

The conventional wisdom is that a software-defined network (SDN) operates under the premise that the logically centralized control plane has an accurate representation of the actual data plane state. Unfortunately, bugs, misconfigurations, faults or attacks can introduce inconsistencies that undermine correct operation. Previous work in this area,...

Software Defined Networking aims to separate network control and data plane by moving the control logic from network elements into a logically-centralized controller. Using a well-defined, unified control-channel protocol, such as OpenFlow, the controller is able to configure the forwarding behavior of data plane devices. Here, the OpenFlow protoco...

The majority of Internet video traffic today is delivered via HTTP Adaptive Streaming (HAS). Recent studies concluded that pure client-driven HAS adaptation is likely to be sub-optimal, given clients adjust quality based on local feedback. In [1], we introduced a network-assisted streaming architecture (BBGDASH) that provides bounded bitrate guidan...

Compared to earlier mobile network generations, the 5G system architecture has been significantly enhanced by the introduction of network analytics functionalities and ex- tended capabilities of interacting with third party Application Functions (AFs). Combining these capabilities, new features for Quality of Experience (QoE) estimation can be desi...

The conventional wisdom is that a software-defined network (SDN) operates under the premise that the logically centralized control plane has an accurate representation of the actual data plane state. Nevertheless, bugs, misconfigurations, faults or attacks can introduce inconsistencies that undermine correct operation. Previous work in this area, h...

Web performance is widely studied in terms of load times, numbers of objects, object sizes, and total page sizes. However, for all these metrics, there are various definitions, data sources, and measurement tools. These often lead to different results and almost all studies do not provide sufficient details about the definition of metrics and the d...

The ongoing network softwarization trend holds the promise to revolutionize network infrastructures by making them more flexible, reconfigurable, portable, and more adaptive than ever. Still, the migration from hard-coded/hard-wired network functions toward their software-programmable counterparts comes along with the need for tailored optimization...

The increase in video traffic and the end-user demands for high-quality videos have triggered academia and industry to find novel mechanisms for media distribution. Among the available streaming services, HTTP adaptive streaming (HAS) is being the de facto standard for multi-bitrate streaming. Recent studies show that the bitrate adaptation of clie...

Scalable user- and application-aware resource allocation for heterogeneous applications sharing an enterprise network is still an unresolved problem. The main challenges are: (i) How to define user- and application-aware shares of resources? (ii) How to determine an allocation of shares of network resources to applications? (iii) How to allocate th...

HTTP Adaptive Streaming (HAS) is the de-facto standard for video delivery over the Internet. It enables the dynamic adaptation of video quality by splitting the video clip into small segments and providing multiple quality levels per segment. Current HAS streaming services typically utilize segments of equal durations. However, this leads to video...

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...

The large share of traffic in the Internet generated by video streaming services puts high loads on access and aggregation networks, resulting in high costs for the content delivery infrastructure. To reduce the bandwidth consumed while maintaining a high playback quality, video players use policies that control and limit the buffer level by using...

This chapter discusses prospects of QoE management for future networks and applications. After motivating QoE management, it first provides an introduction to the concept by discussing its origins, key terms and giving an overview of the most relevant existing theoretical frameworks. Then, recent research on promising technical approaches to QoE-dr...

Both, in AAL and ELE, a multitude of heterogeneous applications, involving different stakeholders, have to communicate via a common network environment. Hence, infrastructures have to become pervasive, with an increasing number of distributed devices that will need to communicate between themselves, as well as with centralized services. Moreover, i...

Enterprise applications like SAP are part of the day-to-day work of a large number of employees. Similar to many modern applications, enterprise applications are often implemented in a distributed fashion and consequently suffer from network degradations resulting in impairments like increased loading delays. While the influence of these impairment...

Reproducing research results, as it is required for peer review, can be a time-consuming and difficult task. In this work, we propose three approaches to improve the way of how research results can be substantiated and discuss their applicability. Our proposals are based on a brief study on evaluation methods (for SDN research) and insights from a...

Managing quality of experience (QoE) is now widely accepted as a critical objective for multimedia applications and the supporting communication systems. In general, QoE management encompasses: (1) monitoring of the key influence factors and QoE indicators, and (2) deciding on the appropriate control actions as specified by the management goal. Man...

This article investigates several network-assisted streaming approaches that rely on active cooperation between video streaming applications and the network. We build a Video Control Plane that enforces Video Quality Fairness among concurrent video flows generated by heterogeneous client devices. For this purpose, a max-min fairness optimization pr...

Software Defined Networking (SDN) has emerged as a promising networking paradigm overcoming various drawbacks of current communication networks. The control and data plane of switching devices is decoupled and control functions are centralized at the network controller. In SDN, each new flow introduces additional signaling traffic between the switc...

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...

The 28th International Teletraffic Congress (ITC 28) was held on 12--16 September 2016 at the University of W\"urzburg, Germany. The conference was technically cosponsored by the IEEE Communications Society and the Information Technology Society within VDE, and in cooperation with ACM SIGCOMM. ITC 28 provided a forum for leading researchers from ac...

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...

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...

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...

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...

This paper investigates several network-assisted streaming approaches which rely on active cooperation between video streaming applications and the network. We build a Video Control Plane which enforces Video Quality Fairness among concurrent video flows generated by heterogeneous client devices. To this purpose, a max-min fairness optimization pro...

The vast majority of Internet traffic is carried by content delivery networks. A high potential to bring content even closer to consumers and to reduce energy cost is achieved by the nano data center (NaDa) concept that has been proposed in recent work. In this approach the capacity available on small devices such as home gateways is used to suppor...

In this paper we investigate several network-assisted streaming approaches which rely on active cooperation between video streaming applications and the network. We build a Video Control Plane which enforces Video Quality Fairness among concurrent video flows generated by heterogeneous client devices. To the purpose, a max-min fairness optimization...

Today’s enterprise services and business applications are often centralized in a small number of data centers. Employees located at branches and side offices access the computing infrastructure via the internet using thin client architectures. The task to provide a good application quality to the employers using a multitude of different application...