An Empirical Study of the I2P Anonymity Network and its Censorship Resistance

Tor and I2P are well-known anonymity networks used by many individuals to protect their online privacy and anonymity. Tor's centralized directory services facilitate the understanding of the Tor network, as well as the measurement and visualization of its structure through the Tor Metrics project. In contrast, I2P does not rely on centralized directory servers, and thus obtaining a complete view of the network is challenging. In this work, we conduct an empirical study of the I2P network, in which we measure properties including population, churn rate, router type, and the geographic distribution of I2P peers. We find that there are currently around 32K active I2P peers in the network on a daily basis. Of these peers, 14K are located behind NAT or firewalls. Using the collected network data, we examine the blocking resistance of I2P against a censor that wants to prevent access to I2P using address-based blocking techniques. Despite the decentralized characteristics of I2P, we discover that a censor can block more than 95% of peer IP addresses known by a stable I2P client by operating only 10 routers in the network. This amounts to severe network impairment: a blocking rate of more than 70% is enough to cause significant latency in web browsing activities, while blocking more than 90% of peer IP addresses can make the network unusable. Finally, we discuss the security consequences of the network being blocked, and directions for potential approaches to make I2P more resistant to blocking.Comment: 14 pages, To appear in the 2018 Internet Measurement Conference (IMC'18

Automated System to Debug Under-performing Network Flows in Wide Area Networks

Locating the cause of performance losses in large high performance Wide Area Networks (WAN) is an extremely challenging problem. This is because WANs comprise several distributed sub-networks (Autonomous Networks), with their own independent network monitoring systems. Each individual monitoring system has limited or no access to network devices outside its own network. Moreover, conventional network monitoring systems are designed only to provide information about the health of individual network devices, and do not provide sufficient information to monitor endto- end performance – thus, adding severe overhead on debugging end-toend performance issues. In this thesis, an automated tool is designed that requires no special access to network devices and no special software installations on the network devices or end hosts. The system detects performance losses and locates the most likely problem nodes (routers/links) in the network. A key component of this system is the novel hybrid network monitoring/data collection system. The monitoring/data collection sub-system is designed to obtain the best of both active and passive monitoring techniques. Then, pattern analysis algorithms are designed. They locate the causes of performance loss using the data collected from above sub-system. This system is being tested on the GLORIAD (Global Ring Network for Advanced Application Development) network. One of the future goals is to in tegrate this system into the GLORIAD’s network monitoring tool set, to provide end-to-end network monitoring and problem mitigation capabilities

Application of overlay techniques to network monitoring

Measurement and monitoring are important for correct and efficient operation of a network, since these activities provide reliable information and accurate analysis for characterizing and troubleshooting a network’s performance. The focus of network measurement is to measure the volume and types of traffic on a particular network and to record the raw measurement results. The focus of network monitoring is to initiate measurement tasks, collect raw measurement results, and report aggregated outcomes. Network systems are continuously evolving: besides incremental change to accommodate new devices, more drastic changes occur to accommodate new applications, such as overlay-based content delivery networks. As a consequence, a network can experience significant increases in size and significant levels of long-range, coordinated, distributed activity; furthermore, heterogeneous network technologies, services and applications coexist and interact. Reliance upon traditional, point-to-point, ad hoc measurements to manage such networks is becoming increasingly tenuous. In particular, correlated, simultaneous 1-way measurements are needed, as is the ability to access measurement information stored throughout the network of interest. To address these new challenges, this dissertation proposes OverMon, a new paradigm for edge-to-edge network monitoring systems through the application of overlay techniques. Of particular interest, the problem of significant network overheads caused by normal overlay network techniques has been addressed by constructing overlay networks with topology awareness - the network topology information is derived from interior gateway protocol (IGP) traffic, i.e. OSPF traffic, thus eliminating all overlay maintenance network overhead. Through a prototype that uses overlays to initiate measurement tasks and to retrieve measurement results, systematic evaluation has been conducted to demonstrate the feasibility and functionality of OverMon. The measurement results show that OverMon achieves good performance in scalability, flexibility and extensibility, which are important in addressing the new challenges arising from network system evolution. This work, therefore, contributes an innovative approach of applying overly techniques to solve realistic network monitoring problems, and provides valuable first hand experience in building and evaluating such a distributed system

Requirement analysis for building practical accident warning systems based on vehicular ad-hoc networks

An Accident Warning System (AWS) is a safety application that provides collision avoidance notifications for next generation vehicles whilst Vehicular Ad-hoc Networks (VANETs) provide the communication functionality to exchange these notifi- cations. Despite much previous research, there is little agreement on the requirements for accident warning systems. In order to build a practical warning system, it is important to ascertain the system requirements, information to be exchanged, and protocols needed for communication between vehicles. This paper presents a practical model of an accident warning system by stipulating the requirements in a realistic manner and thoroughly reviewing previous proposals with a view to identify gaps in this area

Modeling and Implementation of Wireless Sensor Networks for Logistics Applications

Logistics has experienced a long time of developments and improvements based on the advanced vehicle technologies, transportation systems, traffic network extension and logistics processes. In the last decades, the complexity has increased significantly and this has created complex logistics networks over multiple continents. Because of the close cooperation, these logistics networks are highly dependent on each other in sharing and processing the logistics information. Every customer has many suppliers and vice versa. The conventional centralized control continues but reaches some limitations such as the different distribution of suppliers, the complexity and flexibility of processing orders or the dynamics of the logistic objects. In order to overcome these disadvantages, the paradigm of autonomous logistics is proposed and promises a better technical solution for current logistics systems. In autonomous logistics, the decision making is shifted toward the logistic objects which are defined as material items (e.g., vehicles, containers) or immaterial items (e.g., customer orders) of a networked logistics system. These objects have the ability to interact with each other and make decisions according to their own objectives. In the technical aspect, with the rapid development of innovative sensor technology, namely Wireless Sensor Networks (WSNs), each element in the network can self-organize and interact with other elements for information transmission. The attachment of an electronic sensor element into a logistic object will create an autonomous environment in both the communication and the logistic domain. With this idea, the requirements of logistics can be fulfilled; for example, the monitoring data can be precise, comprehensive and timely. In addition, the goods flow management can be transferred to the information logistic object management, which is easier by the help of information technologies. However, in order to transmit information between these logistic objects, one requirement is that a routing protocol is necessary. The Opportunistic relative Distance-Enabled Uni-cast Routing (ODEUR ) protocol which is proposed and investigated in this thesis shows that it can be used in autonomous environments like autonomous logistics. Moreover, the support of mobility, multiple sinks and auto-connection in this protocol enhances the dynamics of logistic objects. With a general model which covers a range from low-level issues to high-level protocols, many services such as real time monitoring of environmental conditions, context-aware applications and localization make the logistic objects (embedded with sensor equipment) more advanced in information communication and data processing. The distributed management service in each sensor node allows the flexible configuration of logistic items at any time during the transportation. All of these integrated features introduce a new technical solution for smart logistic items and intelligent transportation systems. In parallel, a management system, WSN data Collection and Management System (WiSeCoMaSys), is designed to interact with the deployed Wireless Sensor Networks. This tool allows the user to easily manipulate the sensor networks remotely. With its rich set of features such as real time data monitoring, data analysis and visualization, per-node management, and alerts, this tool helps both developers and users in the design and deployment of a sensor network. In addition, an analytical model is developed for comparison with the results from simulations and experiments. Focusing on the use of probability theory to model the network links, this model considers several important factors such as packet reception rate and network traffic which are used in the simulation and experiment parts. Moreover, the comparison between simulation, experiment and analytical results is also carried out to estimate the accuracy of the design and make several improvements of the simulation accuracy. Finally, all of the above parts are integrated in one unique system. This system is verified by both simulations in logistic scenarios (e.g., harbors, warehouses and containers) and experiments. The results show that the proposed model and protocol have a good packet delivery rate, little memory requirements and low delay. Accordingly, this system design is practical and applicable in logistics

Supporting Cyber-Physical Systems with Wireless Sensor Networks: An Outlook of Software and Services

Sensing, communication, computation and control technologies are the essential building blocks of a cyber-physical system (CPS). Wireless sensor networks (WSNs) are a way to support CPS as they provide fine-grained spatial-temporal sensing, communication and computation at a low premium of cost and power. In this article, we explore the fundamental concepts guiding the design and implementation of WSNs. We report the latest developments in WSN software and services for meeting existing requirements and newer demands; particularly in the areas of: operating system, simulator and emulator, programming abstraction, virtualization, IP-based communication and security, time and location, and network monitoring and management. We also reflect on the ongoing efforts in providing dependable assurances for WSN-driven CPS. Finally, we report on its applicability with a case-study on smart buildings

A Topology Control-Based Self-Organisation in Wireless Mesh Networks

An algorithm for self-organisation that assigns the channels intelligently in multi-radio wireless mesh networks (MR-WMN) is important for the proper operation of MR-WMN. The aim of the self-organisation algorithm is to reduce the overall interference and increase the aggregate capacity of the network. In this paper, we have first proposed a generic self-organisation algorithm that addresses these two challenges. The basic approach is that of a distributed, light-weight, cooperative multiagent system that guarantees scalability. Second, we have evaluated the performance of the proposed self-organisation algorithm for two sets of initialisation schemes. The initialisation process results in a topology control of MR-WMN by way of spatial distribution of connectivity between the mesh nodes. The results have been obtained for realistic scenarios of MR-WMN node densities and topologies. We have shown in addition the need to develop non-transmit power control based algorithms to achieve a further increase in system capacity