ReTrust: attack-resistant and lightweight trust management for medical sensor networks

Wireless medical sensor networks (MSNs) enable ubiquitous health monitoring of users during their everyday lives, at health sites, without restricting their freedom. Establishing trust among distributed network entities has been recognized as a powerful tool to improve the security and performance of distributed networks such as mobile ad hoc networks and sensor networks. However, most existing trust systems are not well suited for MSNs due to the unique operational and security requirements of MSNs. Moreover, similar to most security schemes, trust management methods themselves can be vulnerable to attacks. Unfortunately, this issue is often ignored in existing trust systems. In this paper, we identify the security and performance challenges facing a sensor network for wireless medical monitoring and suggest it should follow a two-tier architecture. Based on such an architecture, we develop an attack-resistant and lightweight trust management scheme named ReTrust. This paper also reports the experimental results of the Collection Tree Protocol using our proposed system in a network of TelosB motes, which show that ReTrust not only can efficiently detect malicious/faulty behaviors, but can also significantly improve the network performance in practice.     

Fuzzy logic–based distributed clustering protocol to improve energy efficiency and stability of wireless smart sensor networks for farmland monitoring systems

Wireless smart sensor networks (WSSNs) are emerging as the physical backbone of the internet of things (IoT) technology. On the basis of the IoT platform, web‐based systems and services are been developing such as e‐surveillance, industrial‐IoT, and precision agriculture. For farmland monitoring systems, WSSNs need to be scalable in terms of coverage area. Sensor nodes are energy‐constrained devices, and hence, many energy‐efficient clustering protocols are developed in the literature. But these methods overload the cluster leaders (CLs) with cluster computation and data communication costs. An improper CL selection may lead to the early death of such nodes and hence does not prolong the network lifetime stability. We propose a fuzzy logic (FL)–based distributed clustering protocol to enhance the energy efficiency of WSSN while maximizing the coverage area. The load of CLs is shared by originators and super‐CLs (SCLs) selected in the network. The wireless link and received signal strength (RSS) are greatly affected by environmental conditions and thus cannot be considered as ideal network parameters. We use FL systems to tackle the uncertainty of such network parameters. The proposed protocol is simulated for different scalable WSSNs. The results indicate that the proposed protocol provides better lifetime stability than the recent conventional protocols. The functionalities of the protocol are proposed considering the recent wireless standards. Hence, the proposed protocol can be suitably implemented for farmland monitoring systems.     

Failure detectors for wireless sensor-actuator systems

Wireless sensor-actuator systems (WSAS) offer exciting opportunities for emerging applications by facilitating fine-grained monitoring and control, and dense instrumentation. The large scale of such systems increases the need for such systems to tolerate and cope with failures, in a localized and decentralized manner. We present abstractions for detecting node failures and link failures caused by topology changes in a WSAS. These abstractions were designed and implemented as a set of reusable components in nesC under TinyOS. Results, which demonstrate the performance and viability of the abstractions, based on experiments on an 80 node testbed are presented. In the future, these abstractions can be extended to detect and cope with larger classes of failures in WSAS.     

DL-assisted programmable multilayer network application awareness system for IP-over-EON

In order to realize real-time and fine-granularity network monitoring and adjustment,and satisfy the specific QoS demands of various applications,a deep learning (DL) assisted programmable multilayer network application performance awareness system for IP-over-EON was proposed.The distributed network monitoring based on network application performance awareness was combined with centralized network management.The multilayer and fine-grained network monitoring was implemented by distributed network monitoring,and the data analysis through DL was performed.Experimental results indicate that by combining distributed and centralized processing seamlessly,the proposed network monitoring system can not only realize timely and automatic network control and management but also provide superior scalability.     

A novel scheme using the information of departure processes fordelay guarantees of distributed VBR traffic

In this paper, we consider the problem of providing delay guarantees in a distributed environment, e.g., a wireless network or a cable network. In a distributed environment, the information of the arrival process is, in general, not available to the network. Due to the lack of such information, traffic regulators and scheduling policies discussed in the literature cannot be directly applied. To cope with the problem, we propose a distributed traffic regulator (DTR) that uses the information of the departure process. Based on such DTRs, we propose the distributed earliest deadline first (DEDF) scheduling policy. For the DEDF scheme, we derive an admission-control criterion and show that the maximum delay can be guaranteed if the criterion is satisfied     

互联网运行系统的大数据安全监控系统设计

随着互联网技术的发展,网络安全事件发生的频率越来越高,造成的损失越来越大,外部网站等互联网运行系统成为网络攻击的重灾区。面对日益严峻的网络安全形势,传统的安全监控系统手段已无法应对日趋严重的网络攻击。因此,以某单位互联网运行系统的安全监控系统为例,阐述了大数据安全监控在该系统中的应用原理和相关应用,以期为大数据技术在网络安全中的应用提供实践参考。     

Consumer communications and networking [guest editorial]

A technology that is increasingly visible in the consumer communications domain is peer-to-peer (P2P) communications networks. This is due not mainly to illegal downloads or file sharing, but much more to large-scale consumer communications and distributing contents among subscribers. The main advantage of P2P overlay networks over client-server-based systems is that they do not require central server components; and with respect to management and maintenance, P2P systems are self-managing, in that they can cope with nodes leaving and joining even at a high churn rate. Moreover, P2P systems are very scalable and can cope with a large number of nodes. Typically P2P systems operate as an overlay network on top of the IP layer.     

DYNAMO: A Cross-Layer Framework for End-to-End QoS and Energy Optimization in Mobile Handheld Devices

In this paper, we present the design and implementation of a cross-layer framework for evaluating power and performance tradeoffs for video streaming to mobile handheld systems. We utilize a distributed middleware layer to perform joint adaptations at all levels of system hierarchy - applications, middleware, OS, network and hardware for optimized performance and energy benefits. Our framework utilizes an intermediate server in close proximity of the mobile device to perform end-to-end adaptations such as admission control, intelligent network transmission and dynamic video transcoding. The knowledge of these adaptations are then used to drive "on-device" adaptations, which include CPU voltage scaling through OS based soft realtime scheduling, LCD backlight intensity adaptation and network card power management. We first present and evaluate each of these adaptations individually and subsequently report the performance of the joint adaptations. We have implemented our cross-layer framework (called DYNAMO) and evaluated it on Compaq iPaq running Linux using streaming video applications. Our experimental results show that such joint adaptations can result in energy savings as high as 54% over the case where no optimization are used while substantially enhancing the user experience on hand-held systems.     

The monitoring and early detection of Internet worms

After many Internet-scale worm incidents in recent years, it is clear that a simple self-propagating worm can quickly spread across the Internet and cause severe damage to our society. Facing this great security threat, we need to build an early detection system that can detect the presence of a worm in the Internet as quickly as possible in order to give people accurate early warning information and possible reaction time for counteractions. This paper first presents an Internet worm monitoring system. Then, based on the idea of "detecting the trend, not the burst" of monitored illegitimate traffic, we present a "trend detection" methodology to detect a worm at its early propagation stage by using Kalman filter estimation, which is robust to background noise in the monitored data. In addition, for uniform-scan worms such as Code Red, we can effectively predict the overall vulnerable population size, and estimate accurately how many computers are really infected in the global Internet based on the biased monitored data. For monitoring a nonuniform scan worm, especially a sequential-scan worm such as Blaster, we show that it is crucial for the address space covered by the worm monitoring system to be as distributed as possible.     

Monitoring distributed systems

It is suggested that a functional model of monitoring in terms of the generation, processing, dissemination, and presentation of information can help determine the facilities needed to design and construct distributed systems. Implementation issues are also discussed, with attention given to the intrusiveness of monitoring systems and object-based implementation. It is concluded that generic monitoring services are important tools for managing distributed systems and for debugging during system development. Monitoring services may also be needed as part of the application itself, such as in process control and factory automation     

基于信任权重防御Sybil攻击的模型

P2P分布式系统特别容易遭受Sybil攻击,即一个不良用户伪造多个不存在的虚假用户,与网络中普通用户进行交互,进而达到控制网络的目的。防御模型基于社会化网络的信任概念,在SybilGuard基础上提出了路由增加信任权重的方法,用以降低节点与虚假用户交易的概率,实验显示,诚实节点间的交易成功率及节点停留在安全区域内的概率得到提高,增强了系统健壮性。     

A heuristic task assignment algorithm to maximize reliability of adistributed system

Distributed systems potentially provide high reliability owing to the program and data-file redundancy possible. In many applications, high reliability is the major consideration for system design. Previous work has shown that the distribution of programs and data-files can affect the system reliability appreciably, and that redundancy in resources such as computers, programs, and data-files can improve the reliability of a distributed system. This work formulates a practical application for a reliability-oriented distributed task assignment problem which is NP-hard. Then, to cope with this challenging problem, a greedy algorithm is proposed, based on some heuristics, to find an approximate solution. The simulation shows that, in most cases tested, the algorithm finds suboptimal solutions efficiently; therefore, it is a desirable approach to solve these problems     

Programmable virtual network instantiation in IaaS cloud based on SDN

A possible approach to cope with the diversity of future networks is to set up multiple isolated virtual networks on top of a single shared physical substrate, and each virtual network is customized to some specific purposes. However, in the current realization of virtualized infrastructure, the OpenStack infrastructure as a service (IaaS) cloud, whose isolation and programmability are limited in terms of scalability and performance. To overcome these limitations, we propose a solution based on software defined networking (SDN) which is composed of a centralized server and distributed agents. The server has complete view of the whole network substrate, and is responsible for the installation and management of virtual network through the distributed agents. Each agent has the local view of the substrate node. They can manage the local resources, dispatch and filter the inner- programmable virtual network (PVN) traffic based on MAC isolation which is more scalable than virtual local area network (VLAN) and more efficient than GRE. Our prototype implementation shows that this architecture is feasible and provides a better compromise between flexibility and performance than the solo centralized and distributed solutions.     

应用P2P网络实现基于内容的发布订阅系统

构建大规模分布式基于内容的发布订阅系统仍然面临挑战。大多数现存的系统使用简单、事先定义的、静态的覆盖网络拓扑结构,这导致其具有较差的伸缩性和容错性。提出了一个构建于P2P网络之上的基于内容的发布/订阅系统,借助Pastry网络实现了基于内容的路由协议,其路由算法通过集中点机制避免了全局网络广播并且具有自组织和容错的特性,能够处理任意节点或者链路的失效。仿真结果表明该系统具有较好的路由效率和伸缩性,事件代理所需维护的路由表也更小。     

Multilayer traffic engineering for multiservice environments

Multilayer traffic engineering (MLTE) serves to provide cross-layer online network optimization techniques to cope with rapid variations and short-term evolutions in traffic patterns. MLTE extends traffic engineering as it exists in IP/MPLS-based technology toward the multilayer IP/MPLS-over-optical transport network. In addition to the IP/MPLS traffic routing, MLTE exposes much larger adaptation flexibility by building on next-generation automatic switched optical transport networks. These offer fast setup and teardown of end-to-end multi-hop optical connections (lightpaths), which are offered to the IP/MPLS layer as dynamically provisioned capacity. This dynamic nature leads to an IP/MPLS logical topology that can be reconfigured on the fly, and IP/MPLS link capacity that can be up- or downgraded as client traffic demand varies. These MLTE techniques are generally used to increase perceived network performance in terms of throughput or QoS. As such, a MLTE-managed network offers a better than best-effort service. Many types of traditional and novel services are shifting toward IP/MPLS technology. Consequentially, MLTE algorithms and strategies should be conceived with the characteristics of such services in mind. We present a MLTE strategy that can be implemented in a robust and distributed way. This strategy is then taken as the starting point in a study which evaluates its suitability to such services. We show how the strategy can be adapted considering service performance metrics such as end-to-end delay, traffic loss, and routing stability, and how such service optimizations impact general MLTE objectives such as IP/MPLS logical topology mesh size reduction.

Design and implementation of WAP‐based LAN segment management system using RMON MIB

Advances in LAN technology have enabled fast data transmission. However, without effective management of these resources, congestion of networks as well as waste of resources are inevitable. Therefore, it is necessary to supervise, report, and even control, if necessary, the network resource status so that the communication network can be effectively operated without service interruption by monitoring traffic among the hosts. Web‐based network management systems have been developed and applied for remote management without using specific applications. However, such web‐based network management systems have limited manager mobility and poor performance. To overcome such disadvantages, this paper proposes a network management system using wireless communication. Copyright © 2003 John Wiley & Sons, Ltd.     

A Distributed Intelligent Broadcasting Protocol for Mobile Ad Hoc Networks

The control and routing performances of mobile ad hoc networks (MANETs) depend upon the efficiency of the network-wide broadcasting schemes that are in place. Ad hoc networks are often characterized by poor infrastructure quality, limited resources, dynamic variation and a need for mobility; therefore, ease of deployment, adaptability and potential for energy-savings are the primary drivers considered in the design of typical broadcasting schemes. This paper proposes a distributed intelligent broadcasting protocol (DIBP) that is capable of dynamically determining the broadcasting nodes in a MANET, based upon the distribution of network nodes. This eliminates the need for active network monitoring and periodical maintenance is not required. In addition, the distributed intelligent broadcasting protocol employs an adjustable parameter for determining the broadcasting node, broadcasting timing and the number of broadcasting nodes. This parameter can be changed dynamically based on different operational requirements; such as energy savings, hop count, network delay and other similar targets. Simulations of networks employing the protocol yield results showing that the DIBP performs better in terms of delivery delay, number of rebroadcast nodes, and delivery ratio.     

Schedulability analysis of real-time traffic in WorldFIP networks: an integrated approach

The WorldFIP protocol is one of the profiles that constitute the European fieldbus standard EN-50170. It is particularly well suited to be used in distributed computer-controlled systems where a set of process variables must be shared among network devices. To cope with the real-time requirements of such systems, the protocol provides communication services based on the exchange of periodic and aperiodic identified variables. The periodic exchanges have the highest priority and are executed at run time according to a cyclic schedule. Therefore, the respective schedulability can be determined at pre-run-time when building the schedule table. Concerning the aperiodic exchanges, the situation is different since their priority is lower and they are bandied according to a first-come-first-served policy. In this paper, a response-time-based schedulability analysis for the real-time traffic is presented. Such analysis considers both types of traffic in an integrated way, according to their priorities. Furthermore, a fixed-priorities-based policy is also used to schedule the periodic traffic. The proposed analysis represents an improvement relative to previous work and it can be evaluated online as part of a traffic online admission control. This feature is of particular importance when a planning scheduler is used, instead of the typical offline static scheduler, to allow online changes to the set of periodic process variables.     

Internet tomography

Today's Internet is a massive, distributed network which continues to explode in size as e-commerce and related activities grow. The heterogeneous and largely unregulated structure of the Internet renders tasks such as dynamic routing, optimized service provision, service-level verification, and detection of anomalous/malicious behavior increasingly challenging tasks. The problem is compounded by the fact that one cannot rely on the cooperation of individual servers and routers to aid in the collection of network traffic measurements vital for these tasks. In many ways, network monitoring and inference problems bear a strong resemblance to other "inverse problems" in which key aspects of a system are not directly observable. Familiar signal processing problems such as tomographic image reconstruction, system identification, and array processing all have interesting interpretations in the networking context. This article introduces the new field of network tomography, a field which we believe will benefit greatly from the wealth of signal processing theory and algorithms