Wireless ATM LAN with and without infrastructure

We consider wireless ATM concepts for small LANs, especially for SOHO and future consumer applications. We describe a wireless ATM LAN framework architecture that supports wireless ATM communications in environments with and without fixed ATM infrastructure. For the configuration with an ATM infrastructure, a distributed ATM switched backbone is proposed, which enables a smart ATM switching element to be embedded in every wireless and fixed access point. For bandwidth efficiency and ease of operation (place-and-play), we also propose an ad hoc wireless ATM LAN concept based on the same 5 GHz wireless ATM air interface as is currently under standardization in the ETSI/BRAN and ATM Forum. Unlike CSMA-based ad hoc systems such as HIPERLAN and IEEE802.11, our ad hoc wireless ATM system makes QoS management feasible in an infrastructureless environment by using resource reservation and scheduled medium access protocol. Since cost scalability is essential throughout our system design, we consider forwarding between ad hoc subnets and interworking with the fixed network as important but optional features     

Mesh networks: commodity multihop ad hoc networks

In spite of the massive efforts in researching and developing mobile ad hoc networks in the last decade, this type of network has not yet witnessed mass market deployment. The low commercial penetration of products based on ad hoc networking technology could be explained by noting that the ongoing research is mainly focused on implementing military or specialized civilian applications. On the other hand, users are interested in general-purpose applications where high bandwidth and open access to the Internet are consolidated and cheap commodities. To turn mobile ad hoc networks into a commodity, we should move to more pragmatic "opportunistic ad hoc networking" in which multihop ad hoc networks are not isolated self-configured networks, but rather emerge as a flexible and low-cost extension of wired infrastructure networks coexisting with them. Indeed, a new class of networks is emerging from this view: mesh networks. This article provides an overview of mesh networking technology. In particular, starting from commercial case studies we describe the core building blocks and distinct features on which wireless mesh networks should be based. We provide a survey of the current state of the art in off-the-shelf and proprietary solutions to build wireless mesh networks. Finally, we address the challenges of designing a high-performance, scalable, and cost-effective wireless mesh network.     

Efficient routing for wireless mesh networks using a backup path

Wireless mesh networks (WMNs) have a proven record in providing viable solutions for some of the fundamental issues in wireless networks such as capacity and range limitations. WMN infrastructure includes clusters of mobile ad‐hoc networks connected through a fixed backbone of mesh routers. The mesh network can be constrained severely because of various reasons, which could result in performance degradation such as a drop in throughput or long delays. Solutions to this problem often focus on multipath or multichannel extensions to the existing ad‐hoc routing protocols. In this paper, we propose a novel solution by introducing an alternative path to the mesh backbone that traverses the mobile ad‐hoc networks part of the WMN. The new routing solution allows the mobile nodes (MNs) to establish direct communication among peers without going through the backbone. The proposed alternative ad‐hoc path is used only when the mesh backbone is severely constrained. We also propose, for the first time in WMNs, using MNs with two interfaces, one used in the mesh backbone communication and the other engaged in the ad‐hoc network. A scheme is presented for making the MN aware of link quality measures by providing throughput values to the ad‐hoc on‐demand distance vector protocol. We use piggybacking on route reply messages in ad‐hoc on‐demand distance vector to avoid incurring additional costs. We implemented our solution in an OPNET simulator and evaluated its performance under a variety of conditions. Simulation results show that the alternative ad‐hoc path provides higher throughput and lower delays. Delay analysis show that the throughput improvement does not impose additional costs. Copyright © 2012 John Wiley & Sons, Ltd.     

Securing ad hoc networks

Ad hoc networks are a new wireless networking paradigm for mobile hosts. Unlike traditional mobile wireless networks, ad hoc networks do not rely on any fixed infrastructure. Instead, hosts rely on each other to keep the network connected. Military tactical and other security-sensitive operations are still the main applications of ad hoc networks, although there is a trend to adopt ad hoc networks for commercial uses due to their unique properties. One main challenge in the design of these networks is their vulnerability to security attacks. In this article, we study the threats on ad hoc network faces and the security goals to be achieved. We identify the new challenges and opportunities posed by this new networking environment and explore new approaches to secure its communication. In particular, we take advantage of the inherent redundancy in ad hoc networks-multiple routes between nodes-to defend routing against denial-of-service attacks. We also use replication and new cryptographic schemes, such as threshold cryptography, to build a highly secure and highly available key management service, which terms the core of our security framework     

Non-repudiable authentication and billing architecture for wireless mesh networks

Wireless mesh networks (WMNs) are a kind of wireless ad hoc networks that are multi-hop where packets are forwarded from source to destination by intermediate notes as well as routers that form a kind of network infrastructure backbone. We investigate the security of the recently proposed first known secure authentication and billing architecture for WMNs which eliminates the need for bilateral roaming agreements and that for traditional home-foreign domains. We show that this architecture does not securely provide incontestable billing contrary to designer claims and furthermore it does not achieve entity authentication. We then present an enhanced scheme that achieves entity authentication and nonrepudiable billing.     

Asymptotic Capacity of Infrastructure Wireless Mesh Networks

An infrastructure wireless mesh network (WMN) is a hierarchical network consisting of mesh clients, mesh routers and gateways. Mesh routers constitute a wireless mesh backbone, to which mesh clients are connected as a star topology, and gateways are chosen among mesh routers providing Internet access. In this paper, the throughput capacity of infrastructure WMNs is studied. For such a network with Nc randomly distributed mesh clients, Nr regularly placed mesh routers and Ng gateways, assuming that each mesh router can transmit at W bits/s, the per-client throughput capacity has been derived as a function of Nc , Nr , Ng and W . The result illustrates that, in order to achieve high capacity performance, the number of mesh routers and the number of gateways must be properly chosen. It also reveals that an infrastructure WMN can achieve the same asymptotic throughput capacity as that of a hybrid ad hoc network by choosing only a small number of mesh routers as gateways. This property makes WMNs a very promising solution for future wireless networking.     

An efficient heterogeneous key management approach for secure multicast communications in ad hoc networks

In a mobile wireless ad hoc network, mobile nodes cooperate to form a network without using any infrastructure such as access points or base stations. Instead, the mobile nodes forward packets for each other, allowing communication among nodes outside wireless transmission range. As the use of wireless networks increases, security in this domain becomes a very real concern. One fundamental aspect of providing confidentiality and authentication is key distribution. While public-key encryption has provided these properties historically, ad hoc networks are resource constrained and benefit from symmetric key encryption. In this paper, we propose a new key management mechanism to support secure group multicast communications in ad hoc networks. The scheme proposes a dynamic construction of hierarchical clusters based on a novel density function adapted to frequent topology changes. The presented mechanism ensures a fast and efficient key management with respect to the sequential 1 to n multicast service.     

Power-aware routing protocols in ad hoc wireless networks

An ad hoc wireless network has no fixed networking infrastructure. It consists of multiple, possibly mobile, nodes that maintain network connectivity through wireless communications. Such a network has practical applications in areas where it may not be economically practical or physically possible to provide a conventional networking infrastructure. The nodes in an ad hoc wireless network are typically powered by batteries with a limited energy supply. One of the most important and challenging issues in ad hoc wireless networks is how to conserve energy, maximizing the lifetime of its nodes and thus of the network itself. Since routing is an essential function in these networks, developing power-aware routing protocols for ad hoc wireless networks has been an intensive research area in recent years. As a result, many power-aware routing protocols have been proposed from a variety of perspectives. This article surveys the current state of power-aware routing protocols in ad hoc wireless networks.     

无人机自组网技术研究

在无人机系统中,编组和协同作战能力对提高无人机作站效能和生存能力具有重要意义。无线自组网是一种特殊结构的无线通信网络,其通信依靠节点之间的相互协作,以无线多跳方式完成,因此网络不依赖于任何固定设施,具有自组织和自管理的特性,这种特殊的组网方式使得无线自组网非常适用于无人机系统。介绍了无线自组网的原理,分析了无线自组网应用于无人机系统主要面临的关键技术:路由技术和安全问题。介绍了无线自组网的发展情况和在无人机领域的研究情况。     

Traffic load metrics for multihomed mobile IP and global connectivity

Support for host mobility an essential and necessary feature for roaming users who connect to wireless networks via access points. Access points may have different capabilities, be connected to different networks and be installed by different providers. A mobile host will discover multiple access points in this environment. In such an environment, a mobile host should be able to use the best available connection to communicate with a correspondent host and perhaps use multiple connections for different hosts. In areas with wireless local area network access, pockets with limited or no coverage could exist. Such restricted connectivity could be compensated by neighbor hosts who form an ad hoc network and relay packets until they reach an access point. This paper describes and discusses a proposed solution towards enabling and supporting connectivity in wireless networks. In the proposed solution the network layer software will evaluate and decide which wireless network connections to use. A Running Variance Metric (RVM) and a Relative Network Load(RNL) are used to measure the traffic load of access points in wireless access networks. RVM and RNL can be efficiently used for both infrastructure networks and ad hoc networks. Multihomed Mobile IP (M-MIP) is an extension of Mobile IP that enables mobile hosts to use multiple care-of addresses simultaneously. The extension enhances network connectivity by enabling the mobile host, the home agent and correspondent hosts to evaluate and select the best connection. A proposed gateway architecture using M-MIP that integrates wired IP networks with ad hoc networks is described. The M-MIP and gateway architecture using the RVM and RNL metrics have been validated with simulation studies and results are presented.     

Intrusion detection in wireless ad hoc networks

Intrusion detection has, over the last few years, assumed paramount importance within the broad realm of network security, more so in the case of wireless ad hoc networks. These are networks that do not have an underlying infrastructure; the network topology is constantly changing. The inherently vulnerable characteristics of wireless ad hoc networks make them susceptible to attacks, and it may be too late before any counter action can take effect. Second, with so much advancement in hacking, if attackers try hard enough they will eventually succeed in infiltrating the system. This makes it important to constantly (or at least periodically) monitor what is taking place on a system and look for suspicious behavior. Intrusion detection systems (IDSs) do just that: monitor audit data, look for intrusions to the system, and initiate a proper response (e.g., email the systems administrator, start an automatic retaliation). As such, there is a need to complement traditional security mechanisms with efficient intrusion detection and response. In this article we present a survey on the work that has been done in the area of intrusion detection in mobile ad hoc networks.     

Secure interconnection protocol for integrated Internet and ad hoc networks

Integration of ad hoc networks with the Internet provides global Internet connectivity for ad hoc hosts through the coordination of mobile IP and ad hoc protocols. In a pure ad hoc network, it is difficult to establish trust relationship between two ad hoc hosts due to lack of infrastructure or centralized administration. In this paper, an infrastructure‐supported and distributed authentication protocol is proposed to enhance trust relationships amongst ad hoc hosts. In addition, an effective secure routing protocol (SRP) is discussed to protect the multi‐hop route for Internet and ad hoc communication. In the integrated ad hoc networks with Internet accessibility, the ad hoc routing security deployed with the help of infrastructure has a fundamental impact on ad hoc hosts in term of Internet access, integrity, and authentication. Both analysis and simulation results demonstrate the effectiveness of the proposed security protocol. Copyright © 2007 John Wiley & Sons, Ltd.     

Dynamic QoS Allocation for Multimedia Ad Hoc Wireless Networks

In this paper, we propose an approach to support QoS for multimedia applications in ad hoc wireless network. An ad hoc network is a collection of mobile stations forming a temporary network without the aid of any centralized coordinator and is different from cellular networks which require fixed base stations interconnected by a wired backbone. It is useful for some special situations, such as battlefield communications and disaster recovery. The approach we provide uses CSMA/CA medium access protocol and additional reservation and control mechanisms to guarantee quality of service in ad hoc network system. The reason we choose CSMA protocol instead of other MAC protocols is that it is used in most of currently wireless LAN productions. Via QoS routing information and reservation scheme, network resources are dynamically allocated to individual multimedia application connections.     

Virtual Private Ad Hoc Networking

The fact that a lot of applications require secure communication to take place only between a dynamic subset of distributed devices sharing a common context, is, from a network point of view, very challenging and demanding. Existing technologies such as VPN, P2P overlays or VLANs can only partially respond to these requirements. This observation is the key factor that has driven the proposal of the virtual private ad hoc network concept. Virtual private ad hoc networks (VPAN) are secure and self-organizing overlay networks on top of existing IP infrastructure that use ad hoc networking techniques to enable network connectivity. The underlying IP infrastructure can be the Internet, cellular networks, ad hoc networks, mesh networks … or combinations thereof. A virtual private ad hoc overlay network creates a transparent, shielded and trusted environment for the applications and services running on the participants' devices. The overlay uses internal addressing and ad hoc routing, thereby forming a virtual network on top of the physical infrastructure. In addition, the overlay must be self-organizing and self-maintaining upon member mobility or membership changes. This paper gives an overview of the potential applications, a high-level network architecture and the network challenges emerging from the novel concept of virtual private ad hoc networking. Jeroen Hoebeke was born in Ghent, Belgium in 1979. In 2002 he received the Masters degree in engineering (Computer Science) from the University of Ghent. In August 2002, he joined the Broadband Communications Networks Group. His PhD research includes the development of adaptive routing protocol techniques for mobile ad hoc networks. His main research interests are in ad hoc wireless communications and, more generally, in broadband wireless communications. Within the European MAGNET project, he is actively involved in the development of a network architecture and demonstrator for Personal Networks, with a prime focus on routing and connectivity. Gerry Holderbeke was born in Zottegem, Belgium in 1982. He graduated in Informatics at the University of Ghent in 2004. In August 2004 he joined the Broadband Communications Networks Group where he is currently working as a project developer. His research currently includes the development of an emulator for mobile ad hoc networks. His main research interests are in ad hoc networks and broadband wireless communications and involve routing, addressing and more generally, communication within mobile ad hoc networks and infrastructured networks. Within the European MAGNET project, he is actively involved in the development of a network architecture for Personal Networks, with a prime focus on the implementation of the routing architecture. Ingrid Moerman was born in Gent, Belgium in 1965. She received the degree in Electro-technical Engineering and the Ph.D degree from the Ghent University, Gent, Belgium in 1987 and 1992, respectively. Since 1987, she has been with the Interuniversity Micro-Electronics Centre (IMEC) at the Department of Information Technology (INTEC) of the Ghent University, where she conducted research in the field of optoelectronics. In 1997, she became a permanent member of the Research Staff at IMEC. Since 2000 she is part-time professor at the Ghent University. Since 2001 she has switched her research domain to broadband communication networks. She is currently involved in the research and education on broadband mobile & wireless communication networks and on multimedia over IP. The main research topics related to mobile & wireless communication networks are: wireless access to vehicles (high bandwidth & driving speed), adaptive QoS routing in wireless ad hoc networks, body area networks, protocol boosting on wireless links, design of fixed access/metro part, traffic engineering and QoS support in the wireless access network. Ingrid Moerman is author or co-author of more than 300 publications in the field of optoelectronics and communication networks. Bart Dhoedt received a degree in Engineering from the Ghent University in 1990. In September 1990, he joined the Department of Information Technology of the Faculty of Applied Sciences, University of Ghent. His research, addressing the use of micro-optics to realize parallel free space optical interconnects, resulted in a PhD degree in 1995. After a 2 year post-doc in opto-electronics, he became professor at the Faculty of Applied Sciences, Department of Information Technology. Since then, he is responsible for several courses on algorithms, programming and software development. His research interests are software engineering and mobile & wireless communications. Bart Dhoedt is author or co-author of approximately 70 papers published in international journals or in the proceedings of international conferences. His current research addresses software technologies for communication networks, peer-to-peer networks, mobile networks and active networks. Piet Demeester received the Masters degree in Electro-technical engineering and the Ph.D degree from the Ghent University, Gent, Belgium in 1984 and 1988, respectively. In 1992 he started a new research activity on broadband communication networks resulting in the IBCN-group (INTEC Broadband communications network research group). Since 1993 he became professor at the Ghent University where he is responsible for the research and education on communication networks. The research activities cover various communication networks (IP, ATM, SDH, WDM, access, active, mobile), including network planning, network and service management, telecom software, internetworking, network protocols for QoS support, etc. Piet Demeester is author of more than 300 publications in the area of network design, optimization and management. He is member of the editorial board of several international journals and has been member of several technical program committees (ECOC, OFC, DRCN, ICCCN, IZS, &).     

A survey, classification and comparative analysis of medium access control protocols for ad hoc networks

Recent technological advances in wireless communications offer new opportunities and challenges for wireless ad hoc networking. In the absence of the fixed infrastructure that characterizes traditional wireless networks, control and management of wireless ad hoc networks must be distributed across the nodes, thus requiring carefully designed Medium Access Control (MAC) layer protocols. In this article we survey, classify, and analyze 34 MAC layer protocols for wireless ad hoc networks, ranging from industry standards to research proposals. Through this analysis, six key features emerge: (1) channel separation and access; (2) topology; (3) power; (4) transmission initiation; (5) traffic load and scalability; and (6) range. These features allow us to characterize and classify the protocols, to analyze the tradeoffs produced by different design decisions, and to assess the suitability of various design combinations for ad hoc network applications. The classification and the tradeoff analysis yield design guidelines for future wireless ad hoc network MAC layer protocols.     

Multihop sensor network design for wide-band communications

This paper presents a master/slave cellular-based mobile ad hoc network architecture for multihop multimedia communications. The proposed network is based on a new paradigm for solving the problem of cluster-based ad hoc routing when utilizing existing wireless local area network (WLAN) technologies. The network architecture is a mixture of two different types of networks: infrastructure (master-and-slave) and ad hoc. In this architecture, the participating slave nodes (SNs) in each cluster communicate with each other via their respective master nodes (MNs) in an infrastructure network. In contrast to traditional cellular networks where the base stations are fixed (e.g., interconnected via a wired backbone), in this network the MNs (e.g., base stations) are mobile; thus, interconnection is accomplished dynamically and in an ad hoc manner. For network implementation, the IEEE 802.11 WLAN has been deployed. Since there is no stationary node in this network, all the nodes in a cluster may have to move together as a group. However, in order to allow a mobile node to move to another cluster, which requires changing its point of attachment, a handoff process utilizing Mobile IP version 6 (IPv6) has been considered. For ad hoc routing between the master nodes (i.e., MNs), the Ad hoc On-demand Distance Vector (AODV) Routing protocol has been deployed. In assessing the network performance, field test trials have been carried out to measure the proposed network performance. These measurements include packet loss, delays under various test conditions such as a change of ad hoc route, handoffs, etc.     

Optimal resource allocation in wireless ad hoc networks: a price-based approach

The shared-medium multihop nature of wireless ad hoc networks poses fundamental challenges to the design of effective resource allocation algorithms that are optimal with respect to resource utilization and fair across different network flows. None of the existing resource allocation algorithms in wireless ad hoc networks have realistically considered end-to-end flows spanning multiple hops. Moreover, strategies proposed in wireline networks are not applicable in the context of wireless ad hoc networks, due to their unique characteristics of location-dependent contention. In this paper, we propose a new price-based resource allocation framework in wireless ad hoc networks to achieve optimal resource utilization and fairness among competing end-to-end flows. We build our pricing framework on the notion of maximal cliques in wireless ad hoc networks, as compared to individual links in traditional wide-area wireline networks. Based on such a price-based theoretical framework, we present a two-tier iterative algorithm. Distributed across wireless nodes, the algorithm converges to a global network optimum with respect to resource allocations. We further improve the algorithm toward asynchronous network settings and prove its convergence. Extensive simulations under a variety of network environments have been conducted to validate our theoretical claims.     

Routing security in wireless ad hoc networks

A mobile ad hoc network consists of a collection of wireless mobile nodes that are capable of communicating with each other without the use of a network infrastructure or any centralized administration. MANET is an emerging research area with practical applications. However, wireless MANET is particularly vulnerable due to its fundamental characteristics, such as open medium, dynamic topology, distributed cooperation, and constrained capability. Routing plays an important role in the security of the entire network. In general, routing security in wireless MANETs appears to be a problem that is not trivial to solve. In this article we study the routing security issues of MANETs, and analyze in detail one type of attack-the "black hole" problem-that can easily be employed against the MANETs. We also propose a solution for the black hole problem for ad hoc on-demand distance vector routing protocol.     

基于L-hop路由策略的无线mesh网络的吞吐量

无线mesh网络是最后一英里宽带互联网的可选技术之一。类似于ad hoe网络。在mesh网络中，每个用户节点既是通信终端又提供路由功能；用户节点以ad hoe多跳方式实现与网关的链接，通过网关可以访问因特网。无线mesh网络的吞吐量受到网关带宽的限制。为了捷高mesh网络网关频带的利用效率，现提出基于节点组织ad hoe通信方式和L-hop路由策略。在新的路由策略下，将给出对mesh网络的吞吐量的研究。     

On-Demand Multicast Routing Protocol in Multihop Wireless Mobile Networks

An ad hoc network is a dynamically reconfigurable wireless network with no fixed infrastructure or central administration. Each host is mobile and must act as a router. Routing and multicasting protocols in ad hoc networks are faced with the challenge of delivering data to destinations through multihop routes in the presence of node movements and topology changes. This paper presents the On-Demand Multicast Routing Protocol (ODMRP) for wireless mobile ad hoc networks. ODMRP is a mesh-based, rather than a conventional tree-based, multicast scheme and uses a forwarding group concept; only a subset of nodes forwards the multicast packets via scoped flooding. It applies on-demand procedures to dynamically build routes and maintain multicast group membership. ODMRP is well suited for ad hoc wireless networks with mobile hosts where bandwidth is limited, topology changes frequently, and power is constrained. We evaluate ODMRP performance with other multicast protocols proposed for ad hoc networks via extensive and detailed simulation.