Nicholas J. P. Race

Towards network-wide QoE fairness using openflow-assisted adaptive video streaming

Video streaming is an increasingly popular way to consume media content. Adaptive video streaming is an emerging delivery technology which aims to increase user QoE and maximise connection utilisation. Many implementations naively estimate bandwidth from a one-sided client perspective, without taking into account other devices in the network. This behaviour results in unfairness and could potentially lower QoE for all clients. We propose an OpenFlow-assisted QoE Fairness Framework that aims to fairly maximise the QoE of multiple competing clients in a shared network environment. By leveraging a Software Defined Networking technology, such as OpenFlow, we provide a control plane that orchestrates this functionality. The evaluation of our approach in a home networking scenario introduces user-level fairness and network stability, and illustrates the optimisation of QoE across multiple devices in a network.

Deploying Rural Community Wireless Mesh Networks

Inadequate Internet access is widening the digital divide between town and countryside, degrading both social communication and business advancements in rural areas. Wireless mesh networking can provide an excellent framework for delivering broadband services to such areas. With this in mind, Lancaster University deployed a WMN in the rural village of Wray over a three-year period, providing the community with Internet service that exceeds many urban offerings. The project gave researchers a real-world testbed for exploring the technical and social issues entailed in deploying WMNs in the heart of a small community.

Probing communities: study of a village photo display

In this paper we describe a technology probe aiming to aid understanding of how digital displays can help support communities. Using a simple photo gallery application, deployed in a central social point in a small village and displaying user-generated photos and videos, we have been able to gain an understanding of this setting, field test our device and inspire new ideas directly from members of the community. We explore the process of deploying this display, the response from residents and how the display has taken a place within the community.

OpenLIDS: a lightweight intrusion detection system for wireless mesh networks

Wireless mesh networks are being used to provide Internet access in a cost efficient manner. Typically, consumer-level wireless access points with modified software are used to route traffic to potentially multiple back-haul points. Malware infected computers generate malicious traffic, which uses valuable network resources and puts other systems at risk. Intrusion detection systems can be used to detect such activity. Cost constraints and the decentralised nature of WMNs make performing intrusion detection on mesh devices desirable. However, these devices are typically resource constrained. This paper describes the results of examining their ability to perform intrusion detection. Our experimental study shows that commonly-used deep packet inspection approaches are unreliable on such hardware. We implement a set of lightweight anomaly detection mechanisms as part of an intrusion detection system, called OpenLIDS. We show that even with the limited hardware resources of a mesh device, it can detect current malware behaviour in an efficient way.

uLearn: facilitating ubiquitous learning through camera equipped mobile phones

This paper describes a prototype application based on smartphone devices which supports independent learners within a mobile environment. The techniques employed allow children to rapidly gain access to a large repository of multimedia information through the use of a camera equipped mobile phone or smartphone. More specifically, the use of visual codes (Rohs M. et al., 2004) attached to locations and objects within a museum and park in Lancaster enable the retrieval of Web based information to be triggered by capturing images using the integrated CCD camera. Moreover, the location and orientation of the phone are used as contextual parameters in order to control the specific information to be retrieved by the system. The prototype described in this paper is currently under evaluation by groups of children in Lancaster in order to evaluate the use of this platform for teaching and learning. Our aim was to establish whether or not this user interaction technique could be harnessed for education based applications targeted at young children.

Quality evaluation in peer-to-peer IPTV services

Modern IPTV services are comprised of multiple comprehensive service elements in the entire content delivery chain to maximise the efficiency in networking. Audio-visual content may experience various types of impairments during content ingest, processing, distribution and reception. While some impairments do not cause noticeable distortions to the delivered content, many others such as the network transmission loss can be highly detrimental to the user experience in content consumption. In order to optimise service quality and to provide a benchmarking platform to evaluate the designs for future audio-visual content distribution system, a quality evaluation framework is essential. We introduce such an evaluation framework to assess video service with respect of user perception, while supporting service diagnosis to identify root-causes of any detected quality degradation. Compared with existing QoE frameworks, our solution offers an advanced but practical design for the real-time analysis of IPTV services in multiple service layers.

HomeVisor: Adapting Home Network Environments

This paper considers SDN, and OpenFlow in particular, as technology to develop the next generation of more flexible, configurable and automated home networks. We identify the problems with the current state of the art in home networking, which includes a lack of user engagement in home network maintenance and configuration, Internet bandwidth limitations, and a lack of ISP reconfiguration and troubleshooting tools. We propose HomeVisor, a novel remote home network management tool. In this paper, we evaluate HomeVisors ability to outsource control to an entity outside the home network. This includes the overhead of multiple slices within the home, and the effect of controller latency on network performance.

Stealth distributed hash table: a robust and flexible super-peered DHT

Most Distributed Hash Tables (DHTs) simply consider interconnecting homogeneous nodes on the same overlay. However, realistically nodes on a network are heterogeneous in terms of their capabilities. Because of this, traditional DHTs have been shown to exhibit poor performance in a real-world environment. Additionally, we believe that it is this approach that contributes to a limited exploitation of peer-to-peer technologies. Previous work on super-peers in DHTs was proposed to address these performance issues, however the strategy used is often based on locally clustering peers around individual super-peers. This method of super-peering, however, compromises fundamental features such as load-balancing, resilience and routing efficiency, which traditional DHTs originally promised to offer. We propose a Stealth DHT which addresses the deficiencies of previous super-peer approaches by using the DHT algorithm itself to select the most appropriate super-peer for each message sent by peers. Through simulations and measurements, we show the fitness for purpose of our proposal.

A Scalable User Fairness Model for Adaptive Video Streaming Over SDN-Assisted Future Networks

The growing demand for online distribution of high quality and high throughput content is dominating todays Internet infrastructure. This includes both production and user-generated media. Among the myriad of media distribution mechanisms, HTTP adaptive streaming (HAS) is becoming a popular choice for multi-screen and multi-bitrate media services over heterogeneous networks. HAS applications often compete for network resources without any coordination between each other. This leads to quality of experience (QoE) fluctuations on delivered content, and unfairness between end users, while new network protocols, technologies, and architectures, such as software defined networking (SDN), are being developed for the future Internet. The programmability, flexibility, and openness of these emerging developments can greatly assist the distribution of video over the Internet. This is driven by the increasing consumer demands and QoE requirements. This paper introduces a novel user-level fairness model UFair and its hierarchical variant UFairHA, which orchestrate HAS media streams using emerging network architectures and incorporate three fairness metrics (video quality, switching impact, and cost efficiency) to achieve user-level fairness in video distribution. UFairHA has also been implemented in a purpose-built SDN testbed using open technologies, including OpenFlow. Experimental results demonstrate the performance and feasibility of our design for video distribution over future networks.

Unified and Personalized Messaging to Support E-Learning

The University of Lancaster is a campus based educational institution with over 10,000 members of staff and students on campus during a typical day. The University is currently investigating the use of mobile and smart devices as a platform for delivering mobile learning services and administrative information on a personalized basis. This paper describes two current active areas of development. First, we present an SMS text messaging extension to our Virtual Learning environment (VLE) and describe how this is used to provide personalized messaging. Second, we present our work on a Bluetooth based communications service, named BlueZone, which we use to complement SMS text messaging to offer an alternative communications platform to students. The combination of these technologies provides a unified and cost effective delivery mechanism for communicating with University undergraduates on a large scale.