Showing papers presented at "Testbeds and Research Infrastructures for the DEvelopment of NeTworks and COMmunities in 2006"

Visible light communication using OFDM

Abstract: In this paper wireless communication using white, high brightness LEDs (light emitting diodes) is considered. In particular, the use of OFDM (orthogonal frequency division multiplexing) for intensity modulation is investigated. The high peak-to-average ratio (PAR) in OFDM is usually considered a disadvantage in radio frequency transmission systems due to non-linearities of the power amplifier. It is demonstrated theoretically and by means of an experimental system that the high PAR in OFDM can be exploited constructively in visible light communication to intensity modulate LEDs. It is shown that the theoretical and the experimental results match very closely, and that it is possible to cover a distance of up to one meter using a single LED.

Experience with DETER: a testbed for security research

Abstract: The DETER testbed is shared infrastructure designed for medium-scale repeatable experiments in computer security, especially those experiments that involve malicious code. The testbed provides unique resources and a focus of activity for an open community of academic, industry, and government researchers working toward better defenses against malicious attacks on our networking infrastructure, especially critical infrastructure. This paper presents our experience with the deployment and operation of the testbed, highlights some of the research conducted on the testbed, and discusses our plans for continued development, expansion, and replication of the testbed facility.

Characterizing energy consumption in a visual sensor network testbed

Abstract: In this work we characterize the energy consumption of a visual sensor network testbed. Each node in the testbed consists of a "single-board computer", namely Crossbow's Stargate, equipped with a wireless network card and a Webcam. We assess energy consumption of activities representative of the target application (e.g., perimeter surveillance) using a benchmark that runs (individual and combinations of) "basic" tasks such as processing, flash memory access, image acquisition, and communication over the network. In our characterization, we consider the various hardware states the system switches through as it executes these benchmarks, e.g., different radio modes (sleep, idle, transmission, reception), and Webcam modes (off, on, and acquiring image). We report both steady-state and transient energy consumption behavior obtained by direct measurements of current with a digital multimeter. We validate our measurements against results obtained using the Stargate's on-board energy consumption measuring capabilities.

Emulation versus simulation: a case study of TCP-targeted denial of service attacks

Abstract: In this paper, we investigate the applicability of simulation and emulation for denial of service (DoS) attack experimentation. As a case study, we consider low-rate TCP-targeted DoS attacks. We design constructs and tools for emulation testbeds to achieve a level of control comparable to simulation tools. Through a careful sensitivity analysis, we expose difficulties in obtaining meaningful measurements from the DETER and Emulab testbeds with default system settings, and find dramatic differences between simulation and emulation results for DoS experiments. Our results also reveal that software routers such as Click provide a flexible experimental platform, but require understanding and manipulation of the underlying network device drivers. We compare simulation and testbed results to a simple analytical model for predicting the average size of the congestion window of a TCP flow under a low-rate TCP-targeted attack, as a function of the DoS attack frequency. We find that the analytical model and ns-2 simulations closely match in typical scenarios. Our results also illustrate that TCP-targeted attacks can be effective even when the attack frequency is not tuned to the retransmission timeout. The router type, router buffer size, attack pulse length, attack packet size, and attacker location have a significant impact on the effectiveness and stealthiness of the attack.

WiSNAP: a wireless image sensor network application platform

Abstract: Wireless networks in combination with image sensors open up a multitude of previously unthinkable sensing applications. Capable tools and testbeds for these wireless image sensor networks can greatly accelerate development of complex, yet efficient algorithms that meet application requirements. In this paper, we introduce WiSNAP, a Matlab-based application development platform intended for wireless image sensor networks. It allows researchers and developers of such networks to investigate, design, and evaluate algorithms and applications using real target hardware. WiSNAP offers standardized and easy-to-use application program interfaces (APIs) to control image sensors and wireless motes, which do not require detailed knowledge of the target hardware. Nonetheless, its open system architecture enables support of virtually any kind of sensor or wireless mote. Application examples are presented to illustrate the usage of WiSNAP as a powerful development tool.

Creating a distributed mobile networking testbed environment-through the Living Labs approach

Abstract: Today, new ways of constructing and delivering complex wireless and mobile services require more elaborate and distributed prototyping, testing, and validation facilities. Testbeds are becoming an important tool for integrating technology components into the complex environment of the wireless world and end-users in their daily life. However technology in itself is no longer valid-benefits and usefulness for people in their daily life must be proven before the technology or service can be said to be a success. Living Labs is a user-centred real-life approach to wireless and mobility service and technology design and development (as well as other service areas). The user-centred approach places special emphasis on the need to develop mobile services that are usable, i.e. effective, efficient and satisfying to use, and has full end user integration in the creation and validation processes, which is necessary for gauging market acceptance of the developed prototypes and solutions.

A survey on real world and emulation testbeds for mobile ad hoc networks

Abstract: Mobile ad hoc networks allow for the spontaneous formation of communication networks without dedicated infrastructure. Ad hoc networks are not yet ready for large-scale deployment, because several unsolved research challenges persist. Evaluation methods such as analytical modeling, simulation, emulation, and real world experiments aid in addressing these challenges. There is a strong need for tools to support the task of modeling and evaluation to allow for protocol validation, performance analysis, or proof-of-concept implementations. The choosing of appropriate tools is a time-consuming process, which is often unnecessarily repeated, due to limited knowledge-transfer. We contribute an extensive survey covering real world and emulation testbeds to simplify the choice of appropriate research tools and methodologies in the domain of mobile ad hoc networks. In particular, we identify the key attributes of the aforementioned classes of testbeds and thoroughly discuss the state-of-the-art in literature to form a comprehensive classification of available testbeds.

The development and eStadium testbeds for research and development of wireless services for large-scale sports venues

Abstract: We provide an overview of two closely related testbeds, a development testbed located in the CWSA wireless lab and the unique eStadium testbed located in Purdue's Ross-Ade Football Stadium. In the development testbed we have studied such high-bandwidth, delay-sensitive applications as on-demand streaming of video clips to a large number of wireless clients. This includes optimizing video streaming performance in wireless settings and characterizing the relationship between wireless LAN channel conditions and user-perceived quality. The lessons learned in this development testbed have been scaled up into the fully operational eStadium testbed in Purdue's Ross-Ade Stadium. This large-scale "Living Lab" enables measurements of football fans' use of and experiences with wireless devices to access infotainment content during Purdue football games. These measurements, some of which are summarized in this paper, have led to further research issues that are being addressed in the development lab. These include selective broadcast and multicasting of video clips to enable services to a very large number of wireless clients.

EXTREME: combining the ease of management of multi-user experimental facilities and the flexibility of proof of concept testbeds

Abstract: The experimental testbed for research enabling mobility enhancements (EXTREME) is being developed to allow researchers (i.e. users) of the CTTC to test networking algorithms and technologies in a close-to-real scenario. Basically, EXTREME development focuses on combining the ease of management of multi-user experimental facilities with the flexibility allowed by proof of concept testbeds. Its main goals are: 1) to reduce time from scenario conception by the researcher to the start of the measurements phase, 2) to provide an abstraction of the underlying physical resources to researchers so that they can focus on functionalities rather than low-level configuration issues of the machines, 3) to provide a generic framework to ease the realization and analysis of performance measurements and 4) to allow the rapid adoption and testing of new emerging technologies in a close-to-production environment. The main initial focus of EXTREME is on attaining these goals in wireless environments, which, in general, are more challenging than wired ones. This paper describes its design goals, current status, and some application scenarios where EXTREME has been used.

Cross-layer multi-hop wireless routing for inter-vehicle communication

Abstract: Ad-hoc networking provides a cost-effective support structure for inter-vehicle communication. A decentralized peer-to-peer information dissemination architecture is well suited for automotive applications that need to exchange data having local relevance. Routing, however, is challenge in a vehicular scenario because of the associated dynamism in network topology and variations in driving conditions. In this work we present a cross-layer ad-hoc routing approach based on link connectivity assessment in the network topology. We suggest a framework for proactive enhancements to the optimized link state routing (OLSR) protocol and implement the proposed measures within the protocol format. We further deploy an IEEE 802.11b based vehicular network and demonstrate the effectiveness of link-quality assessment based enhancements in improving the performance of inter-vehicle ad-hoc routing. Through actual test-runs, we show that the enhanced protocol is more responsive to variations in network connectivity and can take preemptive actions in choosing stable and durable routes. The routing methodology suggested in this work leverages cross-layer interactions among the networking, data-link, and physical layers, for enhanced adaptability to varying network topology and link states. The main contributions of this work are as follows: introduction of link-quality assessment methodology for enhanced adaptability of ad-hoc routing in a dynamically changing topology, delineation of the framework of a proactive topology-adaptive ad-hoc routing protocol in a vehicular scenario, and demonstration of effectiveness of the proposed routing enhancements in an IEEE 802.11b based vehicular test-bed.

Creating wireless multi-hop topologies on space-constrained indoor testbeds through noise injection

Abstract: To evaluate routing protocols on a controlled indoor wireless testbed, the radio range must be compressed so that larger multi-hop topologies can be mapped into a laboratory-size area. We propose noise injection as a more flexible option than hardware attenuation and consider methods for mapping real world wireless network topologies onto the testbed. Our experimental results show that additive white Gaussian noise effectively reduces the radio range, without the need for hardware attenuation and careful shielding of wireless cards. We performed experiments for a free space propagation environment. By selecting node positions through an automated procedure, we were able to create a 5-node/4-hop string topology and a random partially connected 6-node topology in a 8m by 8m area with off-the-shelf IEEE 802.11 hardware.

A scalable framework for representation and exchange of network measurements

Abstract: Grid and distributed computing environments are evolving rapidly and driving the development of system and network technologies. The design of applications has placed an increased emphasis upon adapting application behavior based on the performance of the network. In addition, network operators and network researchers are naturally interested in gathering and studying network performance information. This work presents an extensible framework for the storage and exchange of performance measurements. Leveraging existing storage and exchange mechanisms, the proposed framework is capable of handling a wide variety of measurements while delivering performance comparable to that of less flexible, ad-hoc solutions.

The IBM wireless sensor networking testbed

Abstract: This paper describes the wireless sensor networking testbed built at the IBM Zurich Research Laboratory. The testbed has been used to address a wealth of exciting research challenges. Performance evaluations have been carried out with short-range wireless communication technologies, which are highly relevant for sensor networking such as IEEE 802.15.4/ZigBee networks, Bluetooth WPANs, and IEEE 802.11b WLANs. With the testbed, the merits of wireless mesh networking for range extension and reliability enhancement have been explored. New light-weight messaging protocols for communication between sensors and an application server have been tested which allow to bring messaging-oriented middleware down to very low-end sensors and actuators. In addition, the testbed has been used to develop sensor applications for remote metering and location-sensing.

Precision and accuracy of network traffic generators for packet-by-packet traffic analysis

Abstract: Network traffic generators allow video and audio streams to be modelled. 'Bursty' traffic patterns imply packet-by-packet rather than time-averaged analysis to determine the impact on network routers. Due to computer operating system time event scheduling dependencies, the ability to generate accurate packet delivery is compromised. A real-time operating system on an x86 commodity machine is shown to result in greater accuracy and range, but with some loss in precision outside its operating range, compared to a general-purpose Linux kernel.

GEDOMIS: a broadband wireless MIMO-OFDM testbed, design and implementation

Abstract: We present an experimental broadband wireless 4/spl times/4 multiple-input multiple-output (MIMO) OFDM system operating at two well-known WLAN frequency bands: 2.4 GHz and 5.2 GHz. The demonstrator is described placing special emphasis, both at the RF and DSP levels, on the design of a reconfigurable hardware architecture. In the RF section, a new scheme for the design of custom, area-efficient multi-antenna multiband radios is presented. At the DSP level, we describe the synchronization and channel estimation algorithms that may be used in scenarios with multiple transmit antennas. These algorithms take advantage of the cyclic delay diversity (CDD) mechanisms that are currently being proposed for the new IEEE 802.11n standard.

QUETZAL: qualified ultra-wideband testbed for reduced data-rates and location

Abstract: This work presents an UWB testbed for reduced data rates with capabilities of measuring range and location. The transmitter uses time hopping spread spectrum codes to reduce the peak to average ratio in the power spectral density. The pulse generator is based on a class-S digital pulse amplifier and a step recover diode circuit. The antenna subsystem is based on a bow-tie topology. The approach for the receiver is based on a filter bank reducing the complexity of the traditional RAKE receiver. Normalized minimum variance algorithm is proposed for estimating time of arrival exploiting the transmitted pulse train. Positioning estimation is tackled with the extended Kalman filter with TOA bias tracking allowing high accuracy even in non line of sight scenarios.

EVEREST testbed: QoS management evaluation in B3G networks

Abstract: This paper describes the motivation, methodology and implementation approach of the testbed that has been developed in the framework of the EVEREST project. Such testbed is used for demonstrating some of the main concepts addressed within the project, concerning both: common radio resource management strategies and end-to-end QoS architectures and mechanisms for B3G systems based on the UMTS architecture. The complexity of the interaction between B3G systems and the user applications, while dealing with the QoS concept, pushes to develop this kind of emulation platforms, where algorithms and applications can/must be tested in realistic conditions, not achievable by means of off-line simulations.

A testbed demonstrating optical IP switching (OIS) in disaggregated network architectures

Abstract: The lack of a unified control plane does not allow current optical networks to dynamically provision new optical paths. The IETF standardization body has proposed the generalized multi-protocol label switching standard as a solution to this problem. Their efforts however focus on the creation of end-to-end optical trails. This concept is convenient for major service providers, whose network may span a large area, but may not suit smaller network operators. We believe that the future trend of the telecommunication industry is made up of a global network formed by many inter-linked operators of small and medium size. A novel type of network based on a distributed and disaggregated architecture seems to be the best solution to dynamic optical path establishment. In this paper we present an optical testbed implementing the concept of optical IP switching. Central to the system is the optical router that creates new lightpaths depending on encountered traffic flows. The decision making process is completely distributed, and perfectly fits the disaggregated network view. The testbed currently links two universities in Dublin, and may in future be extended to join other existing research networks.

Mapping link SNRs of wireless mesh networks onto an indoor testbed

Abstract: As a platform for synergistic theory-experiment exploration in the field of wireless networking, wireless testbeds have been used to facilitate a broad range of research. From the perspective of system-level wireless emulation, average link SNR is the dominant factor in the performance of a wireless link. Thus, this work seeks to develop a systematic link SNR mapping method that replicates real-world link SNRs on an indoor testbed. The challenge is to optimize the nodes' spatial configuration and transmission powers to overcome the inherent propagation differences, as expressed in terms of pathloss exponents and environmental shadowing, between the real world and a given testbed. To avoid the technical difficulty of "forward mapping" from the real world to the testbed, we have developed a reverse mapping method to turn a testbed configuration with given link SNRs into a corresponding real-world configuration. By inducing the dB link gain differences between the testbed and the real world distance-dependent path loss to have a Gaussian distribution, a close approximation to real-world log-normal shadow fading is achieved. We present results for a variety of indoor and outdoor real-world scenarios.

Testbed for mobile network operator scenarios

Abstract: Wired, wireless, and mobile networks are converging to an all IP heterogeneous network with immense complexity. The underlying access network technologies have a high variance of characteristics. The diversity of multi-mode devices is growing rapidly. These factors have a significant impact on the services running on top of this broad range of different access network technologies. To develop next generation services and solutions for next generation heterogeneous networks, researchers need an adequate environment. This paper presents a "mini" mobile network operator testbed which emulates next generation networks, and enables researchers to design, implement and deploy future services and technologies. The testbed has been used broadly by different research institutions since it became operational back in May 2003.

Pan European Laboratory for next generation networks and services

Abstract: The Pan-European Laboratory (Panlab) is a concept that is being introduced to enable the trial and evaluation of service concepts, technologies, system solutions and business models to the point where the risks associated with launching of these as commercial products will be minimized. The accomplishment of this objective, which should encompass many different European collaborative projects, is an important step towards the establishment of a truly pan European collaboration network. A Common Technology Vision for ICT and the Panlab serves as a Technology Roadmap and as a Strategic Development Guideline for European and global telecommunications. Furthermore it defines a Pan European Laboratory (Panlab) for next generation networks and services in terms of legal and operational general conditions, as well as in terms of technical infrastructure. The result is a framework under which a Panlab should operate. The Panlab will build a full chart of the testing labs and sites available and will present a plan of coordination between these so that the full benefit will be realised. It will pave the way for a clear view of where in Europe is the best place to test a specific technology, system, service or application. It will enable the implementation of a physical infrastructure (interconnection facilities, remote management capabilities, etc.), aiming at establishing integration, testing, validation/verification and possibly certification services for product prototypes of European collaborative projects. The ultimate goal is the establishment of the grounds for a future operational and long-term self-sustainable Pan-European laboratory including a business model that would advise on the continuation as an independent entity.

A testbed for evaluation and analysis of stepping stone attack attribution techniques

Abstract: This paper describes a testbed for experimentally evaluating stepping stone attack attribution techniques. There is a lack of comprehensive experimental evaluation of many different stepping stone attack detection schemes. Therefore, there are no objective, comparable evaluation results on the effectiveness and limitations of these schemes. In this research, we designed and built a scalable testbed environment that can evaluate all existing stepping stone attack attribution schemes reproducibly, provide a stable platform for further research on this area and be easily reconfigured, expanded, and operated with user-friendly interface. This testbed environment has been established in a dedicated stepping stone attack attribution research laboratory. An evaluation of proposed stepping stone techniques is currently underway.

Paving the way for future mobility mechanisms: a testbed for triggering & moving network support

Abstract: Forthcoming wireless communication systems, well represented by the term beyond 3G, are likely to impose some new requirements that go beyond the traditional view on today's networking paradigm. In particular, mobility procedures will no longer be restricted to the change of the point of attachment to the network. The work presented in this paper aims at proving, following a fully experimental approach, the feasibility of some architectural components of a mobility control space, which has been designed so the context of the ambient networks project. Especially, in this study we focused on and successfully realized two concepts, a facility for triggering mobility events and support for moving networks.

A hybrid genetic algorithm for constrained hardware-software partitioning

Abstract: In this article, we propose a novel partitioning method for hardware-software codesign based on a genetic algorithm that has been enhanced for this specific task. Given a high-level program and an area constraint, our software considers different granularities levels to discover the most interesting blocks to be implemented in ad hoc functional units that can then be used as new instructions in a move processor. Various optimizations are conducted to obtain a clean, very fast (in the order of a few seconds) and efficient partitioning on programs ranging from a few to several hundreds of lines of code.

Human action detection and context-aware service implementation in a real-life living space test bed

Abstract: After completion of a real-life living space test bed, the Ubiquitous Home, new sensors have been implemented. In this paper, new functions of the Ubiquitous Home and actual sensed data are presented. Since one of the purposes for the Ubiquitous Home is to evaluate the context-aware services in a real-life situation, a case of context-aware service implementation is also presented. For the service implementation, we have developed a network middleware for consumer appliances and sensors named "UKARI-Core". The outline of the UKARI-Core is described, briefly.

Barcelona's open access network testbed

Abstract: This paper describes the implementation and deployment of a novel architecture for a metropolitan open wireless access network, shared among different service providers. A layered model that differentiates four different actors (user, Wireless Island, Neutral Operator and Service Provider) is introduced, and the mechanism to allow Service Provider selection by the user is detailed. Other key technical issues like AAA, security, redundancy and scalability are also analyzed. This testbed has been used to provide Internet access to different user communities related to our University and as a experimentation platform for service deployment and testing in a real-life scenario.

An integrated testbed for wireless advanced transport protocols and architectures

Abstract: The challenges posed by data communications over both satellite and terrestrial wireless systems make the adoption of adequate countermeasures advisable. In particular, the poor performance experienced by TCP transport protocol in such environments has fed the scientific community to propose novel solutions, from both the protocols and architecture points of view. In order to perform a thorough assessment of such proposals, University of Bologna (UoB) and National Inter-University Consortium for Telecommunications (CNIT) have conceived and set-up an integrated testbed. Its characteristics and capabilities are presented and discussed in this work, focusing in particular on the advantages offered by the ubiquitous remote control of the testbed, provided by a powerful Web interface specifically designed for this purpose.

Light-trail testbed for metro optical networks

Abstract: Telecommunication networks have rapidly added staggering amounts of capacity to their long haul networks at low costs per bit using DWDM technologies. Concurrently, there has been a wave of new access technologies that are driving customers to demand high-speed, robust and customized data services. These dynamics have led to what is called the "metro gap"-the inability to leverage backbone capacity to create and distribute revenue generating services. This paper presents work in progress at Iowa State Universities' High Speed Systems Engineering laboratory to address the metro gap problem. As an initial step towards solving this problem, we demonstrate a streaming media application over a 3 Gbps optical fiber network employing light-trail technology. The testbed and application presented within illustrates a cost-effective platform and outlines high-speed system level design challenges. This complete solution enables high-bandwidth services to move closer to the user premises by combining commercially available network components and emerging network technologies.

Router response to traffic at a bottleneck link

Abstract: Traffic at varying bit rates, packet lengths and packet rates are passed across a bottleneck link. The router response is determined, especially the onset of instability due to excessive CPU load. The paper concludes that it is primarily packet rate that governs the router response. The results are relevant to multimedia streaming applications.

A rendezvous in network experiment-case study of Kuroyuri

Abstract: Rendezvous among experiment entities appear in network experiments both implicitly and explicitly. When the driving system for a network experiment testbed supports such rendezvous, users are free to focus on the content of the experiments, without having to consider details of the rendezvous (conditions, timing, etc.) and their execution. This paper shows typical entity activities in network experiments, especially rendezvous, and presents our approach in the Kuroyuri network experiment driving program.