867 research outputs found

    Security and Privacy Issues in Wireless Mesh Networks: A Survey

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    This book chapter identifies various security threats in wireless mesh network (WMN). Keeping in mind the critical requirement of security and user privacy in WMNs, this chapter provides a comprehensive overview of various possible attacks on different layers of the communication protocol stack for WMNs and their corresponding defense mechanisms. First, it identifies the security vulnerabilities in the physical, link, network, transport, application layers. Furthermore, various possible attacks on the key management protocols, user authentication and access control protocols, and user privacy preservation protocols are presented. After enumerating various possible attacks, the chapter provides a detailed discussion on various existing security mechanisms and protocols to defend against and wherever possible prevent the possible attacks. Comparative analyses are also presented on the security schemes with regards to the cryptographic schemes used, key management strategies deployed, use of any trusted third party, computation and communication overhead involved etc. The chapter then presents a brief discussion on various trust management approaches for WMNs since trust and reputation-based schemes are increasingly becoming popular for enforcing security in wireless networks. A number of open problems in security and privacy issues for WMNs are subsequently discussed before the chapter is finally concluded.Comment: 62 pages, 12 figures, 6 tables. This chapter is an extension of the author's previous submission in arXiv submission: arXiv:1102.1226. There are some text overlaps with the previous submissio

    An All-to-All Multicast Routing Protocol in a Wireless Ad-Hoc Network to Improve Channel Utilization

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    Wireless Ad-hoc network has become more and more popular. Several different multicasting schemes for this type of network have been developed. But most of them are targeting a situation where the total number of senders is much less than the total number of receivers. This thesis analyzes different wireless communication patterns in ad hoc network, the trend for wireless communication and presents a new multicast scheme. It targets an ad-hoc network where all mobile hosts act as both senders and receivers. The proposed scheme in this thesis will reduce overheads by combining data packets that are destined for the same mobile hosts. The action of combining jobs will be done at mobile hosts which are not joined in the multicasting group and only functioned as forwarders

    Mobile Ad-Hoc Networks

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    Being infrastructure-less and without central administration control, wireless ad-hoc networking is playing a more and more important role in extending the coverage of traditional wireless infrastructure (cellular networks, wireless LAN, etc). This book includes state-of the-art techniques and solutions for wireless ad-hoc networks. It focuses on the following topics in ad-hoc networks: vehicular ad-hoc networks, security and caching, TCP in ad-hoc networks and emerging applications. It is targeted to provide network engineers and researchers with design guidelines for large scale wireless ad hoc networks

    Self-stabilizing cluster routing in Manet using link-cluster architecture

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    We design a self-stabilizing cluster routing algorithm based on the link-cluster architecture of wireless ad hoc networks. The network is divided into clusters. Each cluster has a single special node, called a clusterhead that contains the routing information about inter and intra-cluster communication. A cluster is comprised of all nodes that choose the corresponding clusterhead as their leader. The algorithm consists of two main tasks. First, the set of special nodes (clusterheads) is elected such that it models the link-cluster architecture: any node belongs to a single cluster, it is within two hops of the clusterhead, it knows the direct neighbor on the shortest path towards the clusterhead, and there exist no two adjacent clusterheads. Second, the routing tables are maintained by the clusterheads to store information about nodes both within and outside the cluster. There are two advantages of maintaining routing tables only in the clusterheads. First, as no two neighboring nodes are clusterheads (as per the link-cluster architecture), there is no need to check the consistency of the routing tables. Second, since all other nodes have significantly less work (they only forward messages), they use much less power than the clusterheads. Therefore, if a clusterhead runs out of power, a neighboring node (that is not a clusterhead) can accept the role of a clusterhead. (Abstract shortened by UMI.)

    Issues in providing a reliable multicast facility

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    Issues involved in point-to-multipoint communication are presented and the literature for proposed solutions and approaches surveyed. Particular attention is focused on the ideas and implementations that align with the requirements of the environment of interest. The attributes of multicast receiver groups that might lead to useful classifications, what the functionality of a management scheme should be, and how the group management module can be implemented are examined. The services that multicasting facilities can offer are presented, followed by mechanisms within the communications protocol that implements these services. The metrics of interest when evaluating a reliable multicast facility are identified and applied to four transport layer protocols that incorporate reliable multicast

    A Novel Scalable Multicast Mesh Routing Protocol for Mobile ad hoc Networks

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    In recent years the use of portable and wireless equipment is becoming more widespread, and as in many situations communication infrastructure might not be available, wireless networks such as Mobile Ad Hoc Networks (MANETs) are becoming increasingly important. A mobile ad hoc network is a collection of nodes that exchanges data over wireless paths. The nodes in this network are free to move at any time, therefore the network topology changes in an unpredictable way. Since there is no fixed infrastructure support in mobile ad hoc networks, each node functions as a host and a router. Due to mobility, continuous change in topology, limited bandwidth, and reliance on batteries; designing a reliable and scalable routing protocol for mobile ad hoc networks is a challenging task. Multicast routing protocols have been developed for routing packets in mobile ad hoc networks. Existing protocols suffer from overheads and scalability. As the number of senders, groups, and mobility speed increases, the routing overhead and the packet collision increases, and therefore the packet delivery ratio decreases. Thus none of the existing proposed multicast routing protocols perform well in every situation. In this study a novel multicast routing protocol for ad hoc networks is proposed. It is an efficient and scalable routing protocol, and named Network Sender Multicast Routing Protocol (NSMRP). NSMRP is a reactive mesh based multicast routing protocol. A central node called mesh sender (MS) is selected periodically from among the group(s) sender(s) to create one mesh in order to be used in forwarding control and data packets to all multicast group(s) member(s). One invitation message will be periodically flooded to all group(s) member(s) by MS to join the group(s). The proposed routing protocol is evaluated by simulation and compared with a well known routing protocol. The results are analyzed and conclusions are drawn

    RoMR: Robust Multicast Routing in Mobile Ad-Hoc Networks

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    Support for multicast services is crucial for mobile ad-hoc networks (MANETs) to become a viable alternative to infrastructured networks. Efficient multicasting in MANETs faces challenges not encountered in other types of networks such as the mobility of nodes, the tenuous status of communication links, limited resources, and indefinite knowledge of the network topology. This thesis addresses these challenges by providing a framework and architecture with proactive and reactive components to support multicasting in MANETs emphasizing reliability and efficiency of end-to-end packet delivery. The architecture includes the Robust Multicast Routing protocol (RoMR) to provide multicast services to multicast applications. RoMR's proactive component calculates multiple multicast trees based on the prediction of future availability of the links and the assumption that the trees will become disconnected over time. The reactive components respond to changes in the network topology due to the mobility of the nodes and to changes in the multicast group's membership. Sending redundant data packets over multiple paths further enhances the reliability at the cost of an increase in the use of network resources. RoMR uses approximations to Steiner trees during tree formation and forward error correction encoding techniques during packet transmission in order to counteract this increase. To avoid additional network traffic, trees are distributed only when the existing trees cannot be easily patched to accommodate changes in topology or group membership. The novelty of the proposed protocol stems from integrating techniques that have not previously been combined into a multicasting protocol and a unique method to calculate the relative weights of the links. In addition to the specifications of the protocol, a simulation framework was developed to test different implementations of the various components of RoMR. Simulations compared the performance of the basic version of RoMR to a version that ignored link weights, and to a link-state multicast protocol currently being considered by the Internet Engineering Task Force. A statistical analysis of the results showed that RoMR performed better overall, than the other two protocols

    A Modified Shared-tree Multicast Routing Protocol in Ad Hoc Network

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    Mobile ad hoc network is a wireless mobile network that does not have any base station or other central control infrastructure. Design of efficient multicast routing protocols in such network is challenging, especially when the mobile hosts move faster. Shared tree routing protocol is a widely used multicast routing protocol in ad hoc network. However, there are problems in end-to-end delay and network throughput for this protocol. In this paper, we propose a protocol to improve the inherent problem of large end-to-end delay in shared tree method as a modification to the existing multicast Ad hoc On-demand Distance Vector (MAODV) routing for low mobility network. The protocol uses n-hop local ring search to establish new forwarding path and limit flooding region. We then propose an extension to our proposed protocol, which uses periodic route discovery message to improve the network throughput for high mobility network. Simulation results demonstrate the improvement with average end-to-end delay in low mobility case as well as high packet delivery ratio in high mobility cas
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