David Hausheer

Otto-von-Guericke-Universität Magdeburg | OvGU · Faculty of Computer Science

Due to missing IP multicast support on an Internet scale, over-the-top media streams are delivered with the help of overlays as used by content delivery networks and their peer-to-peer (P2P) extensions. In this context, mesh/pull-based swarming plays an important role either as pure streaming approach or in combination with tree/push mechanisms. Ho...

Network management currently undergoes massive changes towards realizing more flexible management of complex networks. Recent efforts include slicing data plane resources by network (link) virtualization and applying operating system design principles to Software Defined Networking to rethink network management. Driven by network operators, network...

Content delivery networks (CDNs) carry more than half of the video content in today's Internet. By placing content in caches close to the users, CDNs help increasing the Quality of Experience, e.g., by decreasing the delay until a video playback starts. Existing works on CDN cache performance focus mostly on distinct caching metrics, such as hit ra...

Network Functions Virtualization (NFV) environments can provide increased elasticity and flexibility for operators, as network-related services can be scaled and moved as needed. Such operations require a seamless transfer of state to provide a service without interruption or performance degradation. In this paper, we propose and analyze a novel ap...

The preferred channel for listening to music is shifting towards the Internet and especially to mobile networks. Here, the overall traffic is predicted to grow by 45% annually till 2021. However, the resulting increase in network traffic challenges mobile operators. As a result, methods are researched to decrease costly transit traffic and the traf...

The rapid growth in the number of insecure portable and stationary devices and the exponential increase of traffic volume makes Distributed Denial-of-Service (DDoS) attacks a top security threat to services provisioning. Existing defense mechanisms lack resources and flexibility to cope with attacks by themselves, and by utilizing other’s companies...

Content Delivery Networks (CDNs) carry an increasing traffic share due to the performance benefits enabled by a global deployment of proxy servers and a request-routing mechanism mapping clients to the closest CDN proxy. The standard approach to map clients/proxies is based on Over the Top (OTT) information such as delay measurements. As this appro...

Peer-to-peer live streaming mechanisms have shown to successfully enable shifting load from costly content servers to streaming clients. Yet, the resulting increase in scalability usually comes at the cost of higher streaming delays caused by the inevitable multi-hop overlay routing among peers. Various mechanisms have been proposed to tune the tra...

Network Functions Virtualization (NFV) stands for a major paradigm shift in computer networks. Despite the flexibility improvements which NFV offers, the commonly used COTS processors show performance limitations compared to specialized circuits. A trade-off can be achieved by reconfigurable hardware like FPGAs, which provide high, guaranteed perfo...

The number of commuters and job-related travelers on public transport is constantly increasing. Often, these spend their time traveling working or consuming news. Consequently demands on mobile network access are rising. Cellular networks, in particular as experienced from within trains, often lack the desired performance. The underlying study exem...

Information Centric Networks(ICN) can employ per-node forwarding strategies to provide an optimal transport service. This paper describes the design of an ICN Forwarder that implements Application-Adaptive Forwarding(AAF): an optimized multipath forwarding strategy for differentiated services that can adapt dynamically to changing link characterist...

Reputation networks are an important building block of distributed systems whenever reliability of nodes is an issue. However, reputation ratings can easily be undercut: colluding nodes can spread good ratings for each other while third parties are hardly able to detect the fraud. There is strong analytical evidence that reputation networks cannot...

A number of today’s over-the-top (OTT) services could greatly benefit from a flexible, efficient, and scalable network-layer multicast support on the Internet. IP multicast showed not to meet these requirements, hindering its adoption in more than individual network islands. As a consequence, Content Delivery Networks (CDNs) emerged as alternative...

Mobile applications such as VoIP, (live) gaming, or video streaming have diverse QoS requirements ranging from low delay to high throughput. The optimization of the network quality experienced by end-users requires detailed knowledge of the expected network performance. Also, the achieved service quality is affected by a number of factors, includin...

Due to missing IP multicast support on an Internet scale, over-the-top media streams are delivered with the help of overlays as used by content delivery networks and their peer-to-peer (P2P) extensions. In this context, mesh/pull-based swarming plays an important role either as a pure streaming approach or in combination with tree/push mechanisms....

Video traffic is the main driver of Internet traffic volume. Thus, content providers and Content Delivery Networks (CDNs) are searching for ways to provide reliable video transmission at a low cost. Hybrid CDN/Peer-to-Peer (P2P) deployments like Akamai NetSession have been shown to combine the high reliability of a CDN backbone and the low cost of...

Adaptive streaming systems gain rising relevance for streaming services. Therefore, the same video is offered in multiple quality versions to clients for adaptation during playback. However, optimizing adaptation in a Quality of Experience (QoE) centric way is difficult. Current systems maximize bit rate, ignoring that different types of adaptation...

Mobile data traffic is increasing rapidly and wireless spectrum is becoming a more and more scarce resource. This makes it highly important to operate mobile networks efficiently. In this paper we are proposing a novel lightweight measurement technique that can be used as a basis for advanced resource optimization algorithms to be run on mobile pho...

Due to missing IP multicast support on an Internet scale, over-the-top media streams are delivered with the help of overlays as used by content delivery networks and their peer-to-peer (P2P) extensions. In this context, mesh/pull-based swarming plays an important role either as pure streaming approach or in combination with tree/push mechanisms. Ho...

A number of today’s over-the-top (OTT) services could greatly benefit from a scalable and efficient network-layer multicast support on the Internet. IP multicast showed to not meet these requirements and, thus, is not available for this purpose. Content Delivery Networks emerged as global alternative but usually end at the border of ISP networks. S...

Dynamic network service chaining allows network operators to apply network services to customer traffic on demand and in a highly flexible manner. SDN and particularly OpenFlow-based approaches have been presented that exploit the flexibility and feature richness of OpenFlow for service chaining in data center settings. These systems often use netw...

Mobile data consumption has seen a considerable rise and is predicted to further increase. This is mainly caused by mobile video consumption. A promising solution is offloading cellular traffic to WiFi. Here, Multipath TCP (MPTCP) enables a seamless user experience for handover and load balancing. However, its influence on the energy consumption of...

Software Defined Network (SDN) solutions bring larger flexibility to network providers and enable improvement of the users' experience for diverse multimedia networked services. Following this successful approach, we propose a Software Defined Health (SDH) solutions, bringing flexibility to health services providers and enabling an improvement of h...

Today’s distributed systems have to work in changing environments and under different working conditions. To provide high performance under these changing conditions, many distributed systems implement adaptive behavior. While simple adaptation through parameter tuning can only react to a limited range of conditions, a switch between different mech...

Recent studies show that an increasing number of over-the-top live streams is delivered over the Internet. For the delivery of those streams, the dynamically changing and potentially large number of users imposes a major challenge. Flash crowds, where the number of users multiplies or significantly drops in a very small time frame, can cause seriou...

Mobile data traffic is increasing rapidly and wireless spectrum is becoming a more and more scarce resource. This makes it highly important to operate the mobile network efficiently. In this paper we are proposing a novel lightweight measurement technique that can be used as a basis for advanced resource optimization algorithms to be run on mobile...

Live streaming of large-scale events such as the Olympic Games with a huge number of viewers is challenging, as the streaming infrastructure needs to scale fast and big, and often in an unpredictable manner. Peer-to-peer (P2P) live streaming (Peercasting) has proven to be beneficial in these scenarios, as resources are scaling inherently with the n...

The increasing amount of over-the-top (OTT) live streams and the lack of global network layer multicast support poses challenges for a scalable and efficient streaming over the Internet. Content Delivery Networks (CDNs) help by delivering the streams to the edge of almost every Internet Service Provider (ISP) network of the world but usually also e...

Internet Service Providers (ISPs) need to cope with a growing amount of over-the-top (OTT) traffic, often without a share in the high revenues of the content providers. To achieve an efficient global delivery of content, today content providers usually employ content delivery networks (CDNs) located at the edge of ISP networks from where content is...

Mobile network operators are expected to face significant traffic increase in the upcoming years. One alternative method is to intelligently move transmissions to times of network underutilization, either on 3G/4G or by offloading to WiFi. Video content, predicted by Cisco to constitute 69% of mobile traffic, offers the greatest potential for offlo...

Network Functions Virtualization (NFV) is a new paradigm to move network tasks currently running on dedicated, vendor-specific hardware to elastic, virtualized environments, similar to IaaS cloud computing. A major challenge of NFV is to reach the performance known from dedicated hardware appliances, which often leverage ASIC, FPGA or NPU-based har...

The access to Online Social Networks (OSN) and to media shared over these platforms account for around 20% of today's mobile Internet traffic. For mobile device users, the access to media content and specifically videos is still challenging and costly. Mobile contracts usually have a data cap and connection qualities can vary greatly, depending on...

The collaboration of Internet service providers (ISPs) and content distribution network (CDN) providers was shown to be beneficial for both parties in a number of recent works. Influencing CDN edge server (surrogate) selection allows the ISP to manage the rising amount of traffic emanating from CDNs to reduce the operational expenditures (OPEX) of...

Today’s overlay-based mobile cloud applications determine a challenge to operators and cloud providers in terms of increasing traffic demands and energy costs. The social-aware management of overlay traffic is a promising optimization approach, which shows potential for improvements by exploiting social information. This paper identifies key stakeh...

Mobile applications such as VoIP, (live) gaming, or video streaming have diverse QoS requirements ranging from low delay to high throughput. The optimization of the network quality experienced by end-users requires detailed knowledge of the expected network performance. Also, the achieved service quality is affected by a number of factors, includin...

The load on cellular networks is constantly increasing. Especially video streaming applications, whose demands and requirements keep growing, put high loads on cellular networks. A solution to mitigate the cellular load in urban environments is offloading mobile connections to WiFi access points, which is followed by many providers recently. Becaus...

Network management systems (NMS) need to support a wide range of application requirements while ensuring an efficient use of networking resources. Application control of Software Defined Networking (SDN) promises to drastically reduce OPEX and increase flexibility of NMS by automatically translating application requirements into network policies an...

Real-time entertainment constitutes the majority of traffic in today's mobile networks. The data volume is expected to increase in the near future, whereas the mobile bandwidth capacity is likely to increase significantly slower. Especially peak hour traffic often leads to overloaded mobile networks and poor user experience. This increases costs fo...

As cloud computing's second wave begins to transform the networking industry, a snapshot of developments in software-defined networking standardization suggests how its components--devices, controllers, applications, service chains, network function virtualization, and interfaces--are maturing.

The power consumption of network devices contributes to a considerable fraction of the energy expenses of data center and service providers. Recently, Software Defined Networking (SDN) has emerged as a novel networking paradigm that allows optimizing the traffic in a variety of ways, ranging from the Ethernet layer to the network layer and above. T...

The peer-to-peer approach can greatly help to cope with highly dynamic live streaming workload by using idle client resources. Yet, P2P streaming typically comes at the cost of increased streaming delays caused by the inevitable multi-hop forwarding of content by peers within the overlay. Various P2P streaming approaches have been proposed aiming a...

An increasing number of households is connected to the Internet via DSL or cable, for which home gateways are required. The optimization of these - caused by their large number - is a promising area for energy efficiency improvements. Since no power models for home gateways are currently available, the optimization of their power state is not possi...

Network service chaining allows composing services out of multiple service functions. Traditional network service functions include, e.g., firewalls, TCP optimizers, web proxies, or higher layer applications. Network service chaining requires flexible service function deployment models. Related work facilitating service chaining include, e.g., the...

Network Function Virtualization is a promising approach for network operators to allow moving network functions from hardware appliances to a pure software-based solution. In combination with software-defined networking concepts, this also allows for flexible service chaining approaches. In this paper, a proof-of-concept implementation of a recentl...

Peer-to-Peer (P2P) has proven to be a scalable approach for content distribution, while reducing the load for the content provider. As P2P systems depend on each node's participation, reciprocal incentive mechanisms for stimulating contribution are a major building block in those systems. However, reciprocal incentive schemes fall short for resourc...

Device-to-Device (D2D) content delivery is a new approach to directly exchange content between mobile devices, which allows to offload traffic from infrastructure-based networks and thus reduces the risk of congestion. While centralized D2D approaches rely on the mobile operator to discover nearby devices and initiate a content transfer, in decentr...

The transmission of video content accounts for a large share of today's Internet traffic. While Video-on-Demand (VoD) substantially contributes to this, live streaming events such as video broadcasts from the Olympic Games can cause very high traffic volumes in the short term as well. Such peaks along with high fluctuations triggered by sudden chan...

Over the years, the demand for high bandwidth services, such as live and on-demand video streaming, steadily increased. The adequate provisioning of such services is challenging and requires complex network management mechanisms to be implemented by Internet service providers (ISPs). In current broadband network architectures, the traffic of subscr...

Location-based services have become increasingly popular in the recent years due to the vast deployment of position-aware devices such as smartphones and tablet PCs and the ubiquitous availability of fast Internet connectivity. Existing location-based services are realized as cloud services, which cause considerably high costs. Furthermore, they ar...

The Peer-to-Peer (P2P) paradigm offers scalable means to perform bulk data distribution, e.g., for small businesses which cannot afford huge upfront investments, by incorporating user's resources in the dissemination process. Due to the proliferation of smartphones with wireless broadband connectivity and the increasing convergence of fixed and mob...

Peer-assisted delivery of video content has shown a great potential to reduce upload bandwidth requirements for content providers by exploiting idle client resources in the video dissemination process. As primary content sources, the servers run by content providers play a critical role in such systems, making their adequate provisioning a key part...

Mobile ad hoc networks (MANETs) represent a crucial alternative to deploy applications in urban areas. In those networks, it is inevitable that all nodes are aware of the current system state to adapt their behavior according to the varying conditions. However, existing decentralized monitoring solutions for MANETs only locate the required informat...

Determining the energy consumption in large-scale overlay simulations is still an open issue as most existing simulation frameworks are agnostic to that aspect. Especially simulations including mobile devices, such as smartphones or tablet PCs, can benefit from having a energy consumption model in simulations such that newly developed large-scale o...

The increased availability and data rates of cellular 3G/4G networks combined with the growing use of mobile applications highly affect the Quality of Experience (QoE) perceived by the end-user. The QoE is affected in two ways: First, the data rates in the networks are low when multiple users simultaneously request content; second, the transmission...

Existing peer-to-peer (p2p) overlays for location-based services suffer from two major drawbacks: (i) they do not store data persistently under peer churn and (ii) they do not allow for the fast retrieval of large files, especially under asymmetric link conditions. This tremendously limits the use of current and future p2p location-based services a...

Internet video streaming causes the second largest transfer volume and is the second fastest growing application class in Internet traffic analysis [3]. In this context, also the streaming of live content becomes increasingly relevant as more traditional broadcasters start delivering content over the Internet. Today, live video streaming services r...