Network Testbeds Research Articles

Monitoring communication outbreaks among an unknown team of actors in dynamic networks

This article investigates the detection of communication outbreaks among a small team of actors in time-varying networks. We propose monitoring plans for known and unknown teams based on generalizations of the exponentially weighted moving average (EWMA) statistic. For unknown teams, we propose an efficient neighborhood-based search to estimate a collection of candidate teams. This procedure dramatically reduces the computational complexity of an exhaustive search. Our procedure consists of two steps: communication counts between actors are first smoothed using a multivariate EWMA strategy. Densely connected teams are identified as candidates using a neighborhood search approach. These candidate teams are then monitored using a surveillance plan derived from a generalized EWMA statistic. Monitoring plans are established for collaborative teams, teams with a dominant leader, as well as for global outbreaks. We consider weighted heterogeneous dynamic networks, where the expected communication count between each pair of actors is potentially different across pairs and time, as well as homogeneous networks, where the expected communication count is constant across time and actors. Our monitoring plans are evaluated on a test bed of simulated networks as well as on the U.S. Senate co-voting network, which models the Senate voting patterns from 1857 to 2015. Our analysis suggests that our surveillance strategies can efficiently detect relevant and significant changes in dynamic networks.

Threshold Models of Cascades in Large-Scale Networks

The spread of new beliefs, behaviors, conventions, norms, and technologies in social and economic networks are often driven by cascading mechanisms, and so are contagion dynamics in financial networks. Global behaviors generally emerge from the interplay between the structure of the interconnection topology and the local agents’ interactions. We focus on the Threshold Model (TM) of cascades first introduced by Granovetter (1978). This can be interpreted as the best response dynamics in a network game whereby agents choose strategically between two actions. Each agent is equipped with an individual threshold representing the number of her neighbors who must have adopted a certain action for that to become the agent's best response. We analyze the TM dynamics on large-scale networks with heterogeneous agents. Through a local mean-field approach, we obtain a nonlinear, one-dimensional, recursive equation that approximates the evolution of the TM dynamics on most of the networks of a given size and distribution of degrees and thresholds. We prove that, on all but a fraction of networks with given degree and threshold statistics that is vanishing as the network size grows large, the actual fraction of adopters of a given action is arbitrarily close to the output of the aforementioned recursion. Numerical simulations on some real network testbeds show good adherence to the theoretical predictions.

Simulation tools for mobile ad hoc networks: a survey

Simulation tools are essential for validating any research idea before it is being implemented. This is very essential for all the researchers irrespective of the field of research. Simulators provide a way for analysing the design.There are many simulation tools available for the network researchers. Network Simulators are used to test the performance of existing or new algorithms and protocols.Some of the simulation tools in networking include OPNET (OPtimized Network Engineering Tool), NS-2 (Network Simulator version 2), OMNET++ (Objective Modular NETwork Testbed in C++), GloMoSim (Global Mobile Information System Simulator), QualNet, NetSim (Network Simulator), JiST/SWANS (Java in Simulation Time/ Scalable Wireless Network Simulator), J-Sim (Java-based simulation) and NS-3 (Network Simulator Version 3). Simulation tools may be open source or commercial. In this paper, both the open source and commercial simulators are discussed. This survey reveals that for simulating large networks, simulators like OPNET, GloMoSim, QualNet, NetSim, JiST/SWANs and NS-3 can be used. For small network simulation NS-2 and J-Sim can be preferred. Open source simulators are poor in documentation. Commercial simulators have good documentation. Based on the requirements of the research, a proper simulation tool can be selected.

Viability of using energy storage for frequency regulation on power grid

This project is about the development and integration of a real-time network simulator in the laboratory using hardware in the loop (HIL) for the purpose of frequency regulation. Frequency regulation is done using the energy storage system (ESS) and a real-time network test bed developed in the smart energy laboratory in Newcastle University. An IEEE Test System was built in the OPAL-RT network simulator to mimic the power grid with renewable energy sources. The study demonstrates the viability of using an ESS to regulate the frequency under an increased penetration of renewable energy sources.

Applied fuzzy heuristics for automation of hygienic drinking water supply system using wireless sensor networks

About 20% of communicable infectious disease is spread by drinking contaminated water. Hence, a real-time in-pipe drinking water quality system using sensor networks is proposed. The proposed prototype Drinking Water Quality Monitoring System (DWQMS) checks for parameters such as pH, temperature, turbidity, oxidation–reduction potential, conductivity, and dissolved oxygen in the drinking water supplied through pipes by the municipality in a fast and efficient manner. In the proposed work, a sensor network that is powered by solar energy is deployed inside the water pipelines to improve the network connectivity and enhance the network lifetime. The prototype designed uses an Energy Aware Multipath Routing Protocol (EAMRP) to prevent the water flow when contamination is detected in a particular pipeline region without interrupting the supply in non-contaminated regions. The key ingredients of the proposed protocol are an energy-efficient algorithm; maximizing the data correlation among sensors; shortest path routing and fast data transmission algorithm to report the water quality to the users quickly; event detection algorithms to assess the water contamination risks in pipes; and fuzzy rule descriptors to predict the water quality as desirable/acceptable/rejected for drinking with better accuracy. The simulation results show that the designed DWQMS acts as an early warning system and outperforms in terms of energy efficiency, detects the contaminants with better accuracy, increases network lifetime, and better estimates the water quality parameters. The proposed algorithms are tested in a small test bed of wireless sensor networks with 20 nodes that monitor the drinking water quality distributed in water distribution mains, which alert the consumers/houses in the water-contaminated regions.

Multi-Vendor Experimental Validation of an Open Source QoT Estimator for Optical Networks

Dramatic increase in data traffic, future diffusion of bandwidth-hungry 5G connectivity and evolving services like virtual reality and cloud will require the implementation of the open and elastic network paradigm on backbone optical networks. To support such growth, operators are aiming at lowering optical network costs by deploying multi-vendor disaggregated optical networks supporting white boxes while maintaining target performances. To make this effort successful, a vendor-agnostic assessment of optical performance is needed, and operators and vendors are working together to achieve this. In this paper, we present the vision of the Open Optical Packet Transport Physical Simulation Environment (PSE) Group of the Telecom Infra Project consortium, which aims at developing an open source framework for quality-of-transmission (QoT) assessment for design and operation of multi-vendor optical networks. We validate the PSE QoT estimator-the optical link emulator (OLE) based on the Gaussian noise (GN) model for nonlinear fiber propagation-by comparison with experimental results on the mixed-fiber test-bed network at Microsoft labs, operated in the C-band by commercial transceivers from eight different vendors, with propagation distances up to 1945 km. An excellent agreement between OLE predictions requiring milliseconds of computational time and measurements has been observed for all channels. The observed ±0.75 dB of accuracy in OLE predictions can be further reduced by including the stimulated Raman scattering in the GN model and with a more accurate capability to estimate power levels and the amount of amplified spontaneous emission noise. Further work will be also required to automate the measurement process of operational parameters from network equipment, especially optical amplifiers, to streamline the overall QoT estimation process.

A Measurement Plane for Optical Networks to Manage Emergency Events

ABSTRACTIn this work, we show a wide geographical area optical network test bed, adopting the mPlane measurement plane for monitoring its performance and to manage software defined network approaches, with some specific tests and procedures dedicated to respond to disaster events and to support emergency networks. Such a test bed includes FTTX accesses, and it is currently implemented to support future 5G wireless services with slicing procedures based on Carrier Ethernet. The characteristics of this platform have been experimentally tested in the case of a damage-causing link failure and traffic congestion, showing a fast reactions to these disastrous events, allowing the user to recharge the initial QoS parameters.

Energy management of cooperative microgrids: A distributed optimization approach

The cooperation of multiple networked microgrids (MGs) can alleviate the mismatch problem between distributed generation and demand and reduce the overall cost of the power system. Energy management with direct energy exchange among MGs is a promising approach for improving energy efficiency. However, existing methods on microgrid cooperation usually overlook the underlying distribution network with operating constraints (e.g., voltage tolerance and power flow constraints). Hence the results may not be applicable to actual systems. This paper studies the energy management problem of multiple MGs that are interconnected by both the direct current (DC) energy exchange network and the alternating current (AC) traditional distribution networks. In our problem, each MG is equipped with renewable energy generators as well as distributed storage devices. In order to handle the non-convex power flow constraints, we exploit the recent results of the exact optimal power flow (OPF) relaxation method which can equivalently transform the original non-convex problem into a second-order cone programming problem and efficiently determine the optimal solution successfully. The objective of our problem is to minimize the overall energy cost in a distribution network consisting of multiple MGs, with the practical operating constraints (e.g., power balance and the battery’s operational constraints) explicitly incorporated. Considering the privacy and scalability, we propose a distributed algorithm with convergence assurance based on the alternating direction method of multipliers (ADMM). We also implement our method based on the model predictive control (MPC) approach in order to handle the forecasting errors of the renewable energy generation. Simulations are made for different MG exchange topologies on three radial distribution network testbeds. Numerical results demonstrate that certain topologies are more favorable than others, and the cooperation strategy for the energy exchange is significantly affected by the MGs’ locations in the distribution network.

Accelerating Innovation that Enhances Resource Recovery in the Wastewater Sector: Advancing a National Testbed Network.

This Feature examines significant challenges and opportunities to spur innovation and accelerate adoption of reliable technologies that enhance integrated resource recovery in the wastewater sector through the creation of a national testbed network. The network is a virtual entity that connects appropriate physical testing facilities, and other components needed for a testbed network, with researchers, investors, technology providers, utilities, regulators, and other stakeholders to accelerate the adoption of innovative technologies and processes that are needed for the water resource recovery facility of the future. Here we summarize and extract key issues and developments, to provide a strategy for the wastewater sector to accelerate a path forward that leads to new sustainable water infrastructures.

Control frameworks in network emulation testbeds: A survey

The network emulation testbed is a promising research area because it provides a platform to fulfill testing requirements, creating emulated environments for conducting experiments. Through such testbeds, heterogeneous resources can be well controlled as emulated environment, and new ideas can be verified in the environment without interfering the real world. Thus, it can be used to reduce the time of the developers for conducting experiment to explore new inventions. Various kinds of network emulation testbed have been around for years, and it can be expected that more testbeds will emerge. To provide an integrated perspective of network emulation testbed, this paper surveys the issues associated in developing network emulation testbeds, including the state-of-the-art of architecture, the interoperability of orchestrating resources, and the way of managing components. Several wide-area, geographically distributed and large-scale network testbeds have been reviewed and discussed. Finally, critical research findings, open issues, and possible future research directions have also been provided.

Deploying WLAN service with OpenFlow technology

SummaryIn this paper, we proposed a feasible software‐defined networking (SDN) wireless local area network (WLAN) solution that leverages OpenFlow technique and provides affordable centralized WLAN service without the proprietary restrictions of centralized thin access point WLAN architecture. On the basis of an SDN‐enabled WLAN architecture with fat access points, we implement and deploy a wireless network test bed, where network administrators can exploit the extensibility and flexibility of OpenFlow‐based SDN switches and controller. Service providers can develop customized application modules and required features. We build our system with open sources and commercial off‐the‐shelf hardware and develop a mechanism to control wireless bandwidth. Field experimental results show that our SDN wireless bandwidth control application can effectively manage bandwidth in a dynamic and flexible way via the SDN WLAN.

A Survey on Large-Scale Software Defined Networking (SDN) Testbeds: Approaches and Challenges

Recently, several large-scale software defined networking (SDN) testbeds have been designed and developed. These SDN testbeds have spurred numerous network researchers to run their prototypes and experiments, as well as to set up novel architectures for the future Internet. Based on these efforts, SDN testbeds are actively contributing to future network research, bringing forth the attention of both academia and industry. In addition, researchers envisage these large-scale SDN testbeds to be the future Internet. In this paper, we present a comprehensive survey and research challenges for large-scale SDN testbeds. We first introduce the related work and background knowledge. Then, an overview of SDN testbeds is presented. In addition, five typical implementations of large-scale SDN testbeds around the world are described in detail, including design objectives, key technologies, deployment, and experiments. Moreover, an in-depth comparison of SDN testbeds is given. Finally, challenges and future works of SDN testbeds are discussed.

Building a lightweight testbed using devices in personal area networks

Various networking applications and systems must be tested before the final deployment. Many of the tests are performed on network testbeds such as Emulab, PlanetLab, etc. These testbeds are large in scale and organize devices in relatively fixed ways. It is difficult for them to incorporate the latest personalized devices, such as smart watches, smart glasses and other emerging gadgets, so they tend to fall short in supporting personalized experiments using devices around users. Moreover, these testbeds commonly impose restrictions on users in terms of when and where to carry out experiments making them clumsy or inconvenient to use. The paper proposes to build a testbed utilizing users? devices in their own personal area networks (PANs). We have designed and implemented a prototype, which we call PANBED. Our experiments show that PANBED allows users to set up different scenes to test applications using a home router, PCs, mobile phones and other equipment. PANBED is light weighted with a size less than 16 KB and it has little impact to the other functions of the PAN. The experiment results also prove the realism, effectiveness, flexibility and convenience of PANBED.

FORGE Toolkit: Leveraging Distributed Systems in eLearning Platforms

While more and more services become virtualized and always accessible in our society, laboratories supporting computer science (CS) lectures have mainly remained offline and class-based. This apparent abnormality is due to several limiting factors, discussed in the literature, such as the high cost of deploying and maintaining computer network testbeds and the lack of standardization for the presentation of eLearning platforms. In this paper, we present the FORGE toolkit, which leverages experimentation facilities currently deployed in international initiatives for the development of e-learning materials. Thus, we solve the institutional challenge mentioned in the ACM/IEEE 2013 CS curricula concerning the access and maintenance of specialized and heterogeneous hardware thanks to a seamless integration with the networking test-bed community. Moreover, this project builds an ecosystem, where teaching and educational materials, tools, and experiments are available under open scheme and policies. We demonstrate how it already meets most of the requirements from the network and communication component of CS 2013 and some of the labs of the Cisco academy. Finally, we present experience reports illustrating the potential benefits of this framework based on the first deployments in four post-graduate courses in prestigious institutions around the world.

Enabling Optical Network Test Bed for 5G Tests

ABSTRACTIn this work, we show some experimental approaches concerning optical network design dedicated to 5G infrastructures. In particular, we show some implementations of network slicing based on Carrier Ethernet forwarding, which will be very suitable in the context of 5G heterogeneous networks, especially looking at services for vertical enterprises. We also show how to adopt a central unit (orchestrator) to automatically manage such logical paths according to quality-of-service requirements, which can be monitored at the user location. We also illustrate how novel all-optical processes, such as the ones based on all-optical wavelength conversion, can be used for multicasting, enabling development of TV broadcasting based on 4G–5G terminals. These managing and forwarding techniques, operating on optical links, are tested in a wireless environment on Wi-Fi cells and emulating LTE and WiMAX systems by means of the NS-3 code.

VINEA: An Architecture for Virtual Network Embedding Policy Programmability

Network virtualization has enabled new business models by allowing infrastructure providers to lease or share their physical network. A fundamental management problem that cloud providers face to support customized virtual network (VN) services is the virtual network embedding. This requires solving the (NP-hard) problem of matching constrained virtual networks onto the physical network. In this paper we present VINEA, a policy-based virtual network embedding architecture, and its system implementation. VINEA leverages our previous results on VN embedding optimality and convergence guarantees, and it is based on a network utility maximization approach that separates policies (i.e., high-level goals) from underlying embedding mechanisms: resource discovery, virtual network mapping, and allocation on the physical infrastructure. We show how VINEA can subsume existing embedding approaches, and how it can be used to design novel solutions that adapt to different scenarios, by merely instantiating different policies. We describe the VINEA architecture, as well as our object model: our VINO protocol and the API to program the embedding policies; we then analyze key representative tradeoffs among novel and existing VN embedding policy configurations, via event-driven simulations, and with our prototype implementation. Among our findings, our evaluation shows how, in contrast to existing solutions, simultaneously embedding nodes and links may lead to lower providers’ revenue. We release our implementation on a testbed that uses a Linux system architecture to reserve virtual node and link capacities. Our prototype can be also used to augment existing open-source “Networking as a Service” architectures such as OpenStack Neutron, that currently lacks a VN embedding protocol, and as a policy-programmable solution to the “slice stitching” problem within wide-area virtual network testbeds.

Low-Rate DoS Attacks Detection Based on Network Multifractal

Low-rate denial of service (LDoS) attacks send periodic pulse sequences with relative low rate to form aggregation flows at the victim end. LDoS attack flows have the characteristics of low average rate and great concealment. It is hard to detect LDoS attack flows from normal traffic due to low rate property. Network traffic measurement shows that aggregate network traffic is multifractal. In order to characterize and analyze network traffic, researchers have developed concise mathematical models to explore complex multifractal structure. Although the LDoS attack flows are very small, it will inevitably lead to the change of multifractal characteristics of network traffic. This paper targets at exploiting and estimating the changes in multifractal characteristics of network traffic for detecting LDoS attack flows. The algorithm of multifractal detrended fluctuation analysis (MF-DFA) is used to explore the change in terms of multifractal characteristics over a small scale of network traffic due to LDoS attacks. Through wavelet analysis, the singularity and bursty of network traffic under LDoS attacks are estimated by using Holder exponent. The difference values (D-value) of Holder exponent of network traffic between normal and under LDoS attack situations are calculated. The D-value is used as the basis to determine LDoS attacks. A detection threshold is set based on the statistical results. The presence of LDoS attacks can be confirmed through comparing D-value with detection threshold. Experiments on detection performance have been performed in the test-bed network and simulation platform. The extensive experimental results are congruent with the theoretical analysis.

Impact of Topology on the Propagation of Cascading Failure in Power Grid

In the past two decades the frequent occurrences of large scale blackouts and catastrophic events has reduced the reliability of power grid to a great extent. A thorough analysis of the propagation of failures, in terms of line outages, combined with the topological characteristics of the grid aids, has been done to take corrective actions to save the system from complete collapse. It also helps to investigate the progress and understand the nature and intensity of blackouts. This motivates to establish the relationship between the network topological characteristics and cascading failure in the power grid. In this paper, the basic topological characteristics of the power network are studied in detail and the average propagation of failure under varying topological conditions is calculated as a branching process parameter. The variation in the mean propagation is studied in detail using a number of test bed networks with the alternate realistic networks derived from the standard IEEE networks imitating the real network conditions. The results confirm a qualitative agreement between the variations in topological parameter and the failure propagation rate in the cascading regime. Based on the analysis mentioned above, data clearly shows that the average failure propagation factor varies linearly with the variations in the statistical metrics.

Role-based intelligent application state computing for OpenFlow distributed controllers in software-defined networking

Software-defined networking, in which a network is programmable and controlled with soft computing techniques, is widely used in various network testbeds. To satisfy the demands of large networks, control planes are constructed with distributed controllers, which are a routine aspect of OpenFlow research. Distributed controllers are scalable and fault tolerant; thus, they can replace centralized controllers in large-scale networks. In the foreseeable future, there will emerge more applications based on soft computing techniques. Because there is scant research on application management, a distributed controller with a role-based mechanism for properly managing applications and their states based on their properties has yet to be developed. Thus, in this study, we propose a systematic approach for classifying applications according to their roles to dynamically deploy applications and their states. Both applications and their states are managed based on their properties, including CPU, memory and network bandwidth. This intelligent mechanism, which computes the overhead of applications, provides a compromise between storage and bandwidth usage in OpenFlow distributed controllers. We propose a hierarchical system to differentiate applications and design a controller module for dynamically determining the status of an application.

Integrated wireless communication system using MANET for remote pastoral areas of Tibet

To reduce the network deployment cost and provide voice, message and low rate data services in remote pastoral areas of Tibet effectively, an integrated wireless communication system utilizing MANET (Mobile Ad hoc Network) is proposed. The sparse mobile devices, assisted with the solar-powered multi-functional standing stations mainly on networking maintenance and routing arrangement, self-organize into a MANET. The topology of the standing stations is designed for networking robust and to simplify the routing method and energy strategy. Then in the OMNeT++ (Objective Modular Network Test bed in C++) simulation, the energy consumption is analysis while adjusting routing with the different energy status of the standing stations. The result shows that the standing stations should adjust routing as well as control the mobile devices' activity level according to the energy states of the standing stations and their adjacent mobile devices.