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Communications and Networking, 2009. ComNet 2009. First International Conference on

Date 3-6 Nov. 2009

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Displaying Results 1 - 24 of 24
  • Link analysis approach to improve detection of fragmentation attacks in Misuse IDS

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (241 KB) |  | HTML iconHTML  

    Intrusion detection system (IDS) is a security technology that attempts to identify and isolate ¿Intrusions¿ against computer systems. The major problem of IDS is the vulnerability to fragment attacks. For this problem we propose a new approach (ARD-FA : Association Rules to Detect Fragment Attack) using data mining techniques of links analyses. We develop this approach and show some improvement in managing the problem. View full abstract»

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  • Control and data channels allocation for Large-Scale UWB-based WSNs

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1159 KB) |  | HTML iconHTML  

    Resource allocation is a critical issue for Wireless Sensor Networks (WSNs) especially for Ultra-Wide Band (UWB) based networks. In this paper, we present frequency allocation scheme for an efficient spectrum management that is able to statically assign control channels and dynamically reuse data channels for Personal Area Networks (PANs) inside a Large-Scale WSN based on UWB technology. The frequency allocation problem is decomposed into two sub-problems: static control channel assignment and dynamic data channel allocation. The goal is two-folded: first, we aim to avoid congestion of control channel, second, to maximize simultaneous communications without suffering from interference in order to enhance throughput, decrease delay and minimize energy consumption. View full abstract»

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  • A prioritized multi-channel multi-time slot MAC protocol for large-scale wireless sensor networks

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2132 KB) |  | HTML iconHTML  

    This paper addresses a new prioritized multichannel multi-time slot MAC protocol (PMCMTP) for large-scale WSNs especially for Ultra-Wide Band (UWB) based networks. To reduce the complexity of resource sharing, the global network is composed of a set of Personal Area Networks (PANs) or cells. According to available resource and PANs duty cycle, PMCMTP can dynamically assign several data channels per PAN and efficiently allocate time slots to each PAN's members. This significantly decreases delay and increases throughput. Through some simulations, we evaluate the performance of the proposed protocol. The results show that PMCMTP ensures an efficient and fair channels allocation between cells permitting, on the one hand, an enhancement of quality-of-service inside each PAN and, on the other hand, a maximization of channel utility. View full abstract»

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  • Resource saving logical topology design for reconfigurable Next Generation Internet backbones

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (326 KB) |  | HTML iconHTML  

    IP over WDM is a promising architecture for the next generation Internet (NGI) backbones. Traffic engineering (TE) for next generation multimedia services is a new challenge for multilayer co-operation within these communication networks. In MPLS/GMPLS based IP over WDM networks, the TE process is accomplished by the establishment of an adequate logical topology, above the underlying optical topology. However, under dynamic traffic pattern, optimal logical topology design or minimization of transitions when reconfiguring it, cannot always lead to efficient traffic handling. Logical topology stability and reconfiguration require resource availability in the network. We are addressing here a mixed integer linear programming (MILP) formulation for the resource saving logical topology design (RSLTD) for reconfigurable network under dynamic traffic pattern. A case study is detailed wishing to show the effectiveness of our proposal. View full abstract»

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  • Performance estimation and power minimizing scheme for a mobile ad hoc networking node

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (341 KB) |  | HTML iconHTML  

    Power consumption will be one of the most crucial issues to realize future communication environments. Mobile ad hoc networks have been the subject of active research for a number of years. They need no infrastructure and are low power consumption network alternative to existing infrastructure. On the other hand, unlike conventional processor platform, a data-driven multi-processor platform based on self-timed elastic pipeline is lower power architecture that establish parallel processing scheme without any runtime overhead. Thus, the power consumption of a data-driven processor is proportional to the throughput. This feature will be effective to predict and minimize power consumption by adjusting it to the demanded performance needed for a mobile ad hoc node. The research proposed in this paper is a first attempt to realize a system that consumes only substantially needed power by estimating the demanded performance and controlling the supplied power. This paper first proposes a method for estimating the demanded performance of a mobile ad hoc node. Then we try to estimate the suitable voltage and we present the data-driven power controlling scheme. We show that the performance estimation method combined with the power minimizing scheme can achieve minimum essential power consumption, 1/10 to 1/100 of the present. View full abstract»

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  • S-Promela: An executable specification security policies language

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB) |  | HTML iconHTML  

    Security Policy constitutes the main basis of a secured system but can be its main vulnerability also since a wrongly configured policy or an inadequate one can be fatal for the system. Even if the network administrator is a high qualified person, the human interventions are error prone. Nevertheless, a formal specification can avoid such problem. This paper aims to give a first step towards a framework allowing to specify and to verify a given policy with respect to an expected one. Hence, we propose in this paper a new all-purpose security policy modeling based on the concepts of processes, channels, constraints, events and actions. This modeling is called all-purpose because it can be easily used to represent the several kinds of security rules i.e. authorization, obligation and prohibition. Moreover, it constitutes the first step towards the proposition of a new executable security specification language. This language, called S-Promela has a syntax supporting authorization, obligation and prohibition rules and a semantics facilitating the validation task. View full abstract»

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  • Analytical jitter model for IP network planning and design

    Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB) |  | HTML iconHTML  

    Traditionally, IP Network planning and design is mostly based on average delay or loss constraints which can often be easily calculated. Jitter, on the other hand, is much more difficult to evaluate but this is particularly important to manage the QoS of real-time and interactive services such as VoIP and streaming video. In this paper, we propose a simple model for the delay jitter that is fast enough to be used in networks design algorithms. It takes into account the packets delay correlation and also the correlation of tandem queues that have a significant impact on the end-to-end jitter. We present simple formulas for the jitter of Poisson traffic in a single queue that can be calculated quickly. We then extend them to the end-to-end jitter of a tagged stream based on a tandem queueing network. The results given by the model are then compared with event-driven simulations. We find that they are very accurate for Poisson traffic over a wide range of traffic loads and more importantly, that they yield conservative values for the jitter so that they can be used in network design procedures. View full abstract»

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  • Proposition and analysis of multi channel cognitive MAC protocols with parallel transmission of traffic and UWB control information

    Page(s): 1 - 9
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (302 KB) |  | HTML iconHTML  

    Cognitive radio and UWB technologies are new radio designs philosophies in order to optimize the spectrum utilization by exploiting the unused and the under-used spectrum in dynamically changing environments. Although the contrasting philosophies of cognitive radio and UWB technology gains can be made by merging these two technologies. In this paper we propose a cognitive radio based on two MAC protocols which work in a cooperative manner. The first is a MAC UWB protocol for control information transmission, while the second is a MAC protocol for narrow or large band traffic transmission (which depend on the primary user physical implementation). We prove then by analyzing the No real time and the real time Markov chains the efficiency of the CS-OFDMA with pre-reservation access protocol to decrease the Forced termination probability and to increase the throughput of cognitive nodes. View full abstract»

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  • An adaptive control algorithm in intelligent home networks

    Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (258 KB) |  | HTML iconHTML  

    The home environment becomes ready to host distributed devices dynamically adapting to service availability and reacting to user location and user activity. Sensors, high definition rendering systems, home gateways, wired and wireless controllable equipments are now available. Many protocols enable connectivity and interaction between devices. However, some challenges remain such as a smart routing protocol. In this paper, we propose an adaptive control algorithm for intelligent routing inside home. Our work is divided on two parts: first, we try to adjust Access router routing zone radius dynamically via a fuzzy inference system for load balancing. Then an energy efficient algorithm to find and maintain routes is proposed. View full abstract»

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  • Vertical handover based on IEEE802.21 and Mobile IPv6 in UMTS/WLAN networks

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (681 KB) |  | HTML iconHTML  

    The internetworking among heterogeneous networks is in demand to provide "always-on" connectivity services. A widespread vision of the fourth generation (4G) mobile networks includes coexistence of current wireless technologies such as WLAN, WiMAX, General Packet Radio Service (GPRS) and Universal Mobile Telecommunications System (UMTS). The major problem that faces next generation wireless networks (NGWN) is vertical handoff management. The existing handoff management protocols are not sufficient to guarantee handoff support that is transparent to the applications in NGWS. In this paper we propose an approach based on IEEE 802.21 MIH and Mobile IPv6 to optimize vertical handover management for multi-interface MN. View full abstract»

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  • Efficient backward compatible allocation mechanism for multi-user CSMA/CA schemes

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (236 KB) |  | HTML iconHTML  

    With the increase of the number of Wireless Local Area Network devices (laptop PC, PDA, cellphones and set-top boxes) multi-user communication get a great interest for future versions of IEEE 802.11 standard. However, current CSMA/CA WLAN protocols do not support multiple transmissions on the same time frequency resource. This hinders these systems from taking a potential increase of the available throughput in dense deployments. In this contribution we propose a new RTS/CTS mechanism destined for WLAN SDMA/OFDMA access. We provide a capacity based analytical framework to assess the performance of these PHY layer techniques from MAC perspective in a multi-user context. Taking into account the MAC overhead it is shown that SDMA provides a substantial gain for multi-user throughput. View full abstract»

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  • Overlay routing efficiency during Internet outages

    Page(s): 1 - 7
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (133 KB) |  | HTML iconHTML  

    Internet communications may have strong reliability requirements and outages may thus have serious consequences. Recovery mechanisms are therefore deployed in networks to mitigate the effects of incidents that hit Internet. This paper proposes to study recovery mechanisms based on overlay routing. We are focusing on the ability for such systems to recover a failing communication, compared to traditional IP routing systems. We propose a model of these mechanisms behaviour deployed in several interconnected networks in reaction to different incidents. Our results point out that overlay routing can increase communications reliability and emphasize the importance of overlay nodes deployment. View full abstract»

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  • A generic model for delegation in security policies

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (315 KB) |  | HTML iconHTML  

    Delegation is the process whereby a user can assign his authorizations to another user. This feature is necessary in today's communication networks principally because it allows the interaction between the entities composing such networks. This paper aims to give a first step toward a framework allowing to, formally, model delegation. Hence, we propose an extension of a previously proposed model by adding delegation and specially handling most of the delegation properties which we find in the literature. For this purpose, we model a delegation request based on two types: the grant and the transfer. We also propose an adapted verification process completing the delegation process. Finally, we discuss the revocation of delegations according to three schemes. View full abstract»

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  • Performance analysis of SCTP protocol in WiFi network

    Page(s): 1 - 5
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (485 KB) |  | HTML iconHTML  

    The Internet Protocol Stack provides a set of transport layer protocols. There are two dominant types of transport layer protocol used in the Internet: UDP (User Datagram Protocol) and TCP (Transmission Control Protocol). The transport layer provides end-to-end information transfer across a network with the quality of service needed by the application. In this paper, we provide a performance comparison of SCTP, TCP and UDP protocols in WLAN environments for different traffic flow: VoIP, video streaming and data traffic. The performance metrics used for this evaluation include throughput, end to end delay and packet loss rate. The comparison of performance of SCTP, UDP and TCP are done using the network simulator NS-2. View full abstract»

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  • Improving 3-dimensional turbo codes using 3GPP2 interleavers

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (389 KB) |  | HTML iconHTML  

    This paper deals with the performance improvement of a 3-dimensional turbo code based on the partial concatenation of the 3GPP2 code with a rate-1 post-encoder. First, we optimize the distance spectrum of the 3-dimensional 3GPP2 turbo code by means of the adoption of a non regular post-encoding pattern. This allows us to increase the minimum Hamming distance and thereby to improve the performance at very low error rates. Then, we propose a time varying construction of the post-encoded parity in order to reduce the observable loss of convergence at high error rates. The different improvement stages are illustrated with simulation results, asymptotical bounds and EXIT charts. View full abstract»

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  • WCDS-induced routing for data-aggregation in wireless sensor networks

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (186 KB) |  | HTML iconHTML  

    Wireless sensor networks (WSNs) are often deployed in harsh environments with little human control, thereby necessitating self organizing and maintenance mechanisms for medium sharing and data routing. Moreover, since sensor nodes operate on energy-limited batteries, designing energy-efficient routing techniques that extend the network lifetime is of a paramount importance. In this paper, we propose WCDS-DCR, a fully distributed, data-centric, routing technique that makes use of an underlying clustering structure induced by the construction of WCDS (Weakly Connected Dominating Set) to prolong network lifetime. WCDS-DCR aims at extending network lifetime through the use of data aggregation (based on the elimination of redundant data packets) by some particular nodes. It also utilizes both the energy availability information and the distances (in number of hops) from sensors to the sink in order to make hop-by-hop, energy-aware, routing decisions. Simulation results show that our solution is scalable, and outperforms existing schemes in terms of network lifetime. View full abstract»

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  • Collaborative strategy learning for distributed network self-configuring

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (403 KB) |  | HTML iconHTML  

    Self-configuration is one of the most important functions of autonomic networks because it determines optimal use of resources during network's operation. However, this task is very complex as it must be performed according to service contracts between users and operators, network's infrastructure and workload. Knowledge Plane is a recently proposed concept to address this complexity by using cognitive tools (learning and reasoning). In this paper, we propose a Knowledge Plane including a distributed and collaborative machine learning method based on inductive logic programming (ILP). The main objective is to achieve distributed self-configuring by learning collaboratively best configuration strategies. We apply it in a practical context (DiffServ) and evaluate effects of this proposal on network's performances and occupation rate. View full abstract»

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  • Achieving broadcasting efficiency in V2X networks with a distance-based protocol

    Page(s): 1 - 8
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (151 KB) |  | HTML iconHTML  

    Vehicular wireless networks are prospective tools which contribute to safer and more efficient roads. Therefore, they require the design and development of new communication protocols that should constitute the building blocks of future vehicular communication architecture. Many works have been carried out in this wide research area. In this paper, we propose a reliable distance-based broadcast protocol to deliver safety information to nodes located in a geographical area when an emergency event occurs. Simulation results show that the proposed protocol achieves its design goal of delivering information in a rapid and efficient manner. Furthermore, we conclude that our proposal performs better in terms of information reception delay as well as redundancy factor as compared to a scheme inspired from previous proposed schemes. View full abstract»

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  • High availability in IMS virtualized network

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (505 KB) |  | HTML iconHTML  

    Virtualization, in telecommunication, has been given great interest over the 20 past years. Migrating operating system instances between physical hosts is one of the most important features of this technology. It allows network administrators to resolve serious problem such us hardware failure, lack in server capacity, while facilitates the management and the upgrade of their systems. With the strong use of Internet Protocol Multimedia Subsystem (IMS) by most of third Generation (3G) network operators as a common infrastructure, live migration may be useful to resolve the overload problem that affects Call Session Control Function (CSCF) components. Our objective is to propose a High availability solution in order to avoid performance degradation. Thus, we aim to proof that when introducing the migration technique within the IMS architecture, we resolve the overload problem and guarantee Quality of Service (QoS) for IMS client. Based on previous work on high availability using virtualization, we describe, in this paper, our methodology and implementation of an experimental scenario using live migration. Then, we evaluate the registration and the session setup delays. The use of migration reduces considerably the delays by 40% for registration and by 38% for session setup. So, we obtain acceptable values compared to the thresholds. View full abstract»

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  • SeGCom: A secure group communication mechanism in cluster-tree wireless sensor networks

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB) |  | HTML iconHTML  

    Security is a challenging issue in Wireless Sensor Networks (WSNs) due to the dual impact of their inherent constraints and their operation in open and harsh environments. The problem of securing a WSN becomes even more complex when considering group communications. In this paper, we address this problem and propose a new security mechanism for group communications in cluster-tree WSNs. We define a group as a set of sensor nodes in the cluster-tree network sharing the same sensory information (e.g. temperature, pressure, etc.). Our objective is to limit the access to the group data exclusively to the members that have securely joined the group. The main contributions of the paper are (1) the proposal of an efficient and secure group management mechanism for cluster-tree networks, and (2) a secure key distribution between group members. Finally, our security analysis shows that the proposed scheme is efficient and secure. View full abstract»

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  • Asynchronous DS-UWB communication using spatiotemporal chaotic waveforms and sequences

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB) |  | HTML iconHTML  

    It is known that in a direct-sequence (DS) ultrawideband (UWB) system, a single type of UWB pulse is used in all bits for all users. In this paper, we address a method to generate varying waveforms based on spatiotemporal chaotic approach. Regarding spreading sequences, we consider the two cases of short and long sequences. In particular, we propose the use of a family of spatiotemporal chaotic systems, namely Piecewise Coupled Map Lattices (PCML), as spatiotemporal chaotic waveforms and spreading sequences. Such sequences are shown to reduce the multi-user interference (MUI) variance with regard to i.i.d. and Gold sequences for both short and long cases. On the other hand, we evaluate and compare the DS-UWB system performance by using conventional waveform such as Gaussian monocycle pulse and PCML pulses. Finally, we show that the use of long PCML codes with PCML pulses, results in an improvement of the system average BER, hence an increase of the system capacity in terms of number of active users. View full abstract»

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  • Comparison of AF and DF relaying for uplink CDMA communications subject to constant multiple access interference cost

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB) |  | HTML iconHTML  

    In radio mobile cellular networks, the users located at the cell border suffer from a bad quality of service (QoS). Cooperative communication is a promising technique that can overcome this weakness by allowing these users to profit from powerful benefits of spatial diversity. Nevertheless, abstraction is usually made on the impact of the additional multiple access interference inherent to relaying. In a previous work, we have optimized amplify-and-forward (AF) relaying scheme subject to a constant multiple access interference cost for CDMA (Code Division Multiple Access) uplink communications. Here, we extend this work by dealing with performance optimization for decode-and-forward (DF) relaying subject to the same cost constraint for the same framework. We compare the performance of both optimized AF and DF schemes for different scenarii. A variety of simulation results reveals that DF relaying provides cellular performance enhancement in terms of BER (Bit Error Rate) over both direct transmission and AF relaying schemes. View full abstract»

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  • Fading effect on the dynamic performance evaluation of OFDMA cellular networks

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB) |  | HTML iconHTML  

    The objective of the present paper is to build a model which permits to capture and analyze the principal impacts of fading and multiuser diversity gain on the dynamic performance of an OFDMA cellular network. To this end, assuming Markovian arrivals and departures of customers that transmit some given data-volumes, as well as some temporal channel variability (fading), we study the mean throughput (and delay) that the network offers to users in the long-term evolution of the system. Explicit formulas are obtained in the case of allocation policies, which may or may-not take advantage of the fading, called respectively opportunistic and non-opportunistic. The main practical results of the present work are the following. Firstly we evaluate for the non-opportunistic allocation the degradation due to fading compared to AWGN (that is, a decrease of at least 13% of the throughput). Secondly, we evaluate the gain induced by the opportunistic allocation. In particular, when the traffic demand per cell exceeds some value (about 2 Mbps in our example), the gain induced by opportunism compensates the degradation induced by fading compared to AWGN. View full abstract»

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  • Multi-radio multi-channel routing metrics in IEEE 802.11s-based wireless mesh networks — And the winner is …

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (256 KB) |  | HTML iconHTML  

    IEEE 802.11s is one of the emerging standards designed to build Wireless Mesh Networks (WMNs) which may serve to extend the coverage of access networks. The default IEEE 802.11s path selection protocol HWMP (Hybrid Wireless Mesh Protocol) is based on the radio-aware Airtime Link Metric (ALM) that outperforms the hopcount metric in single channel multi-hop wireless networks. However, this metric may lead to capacity degradation when multiple channels and/or multi-radio are used. To fully exploit the capacity gain of multiple channels use, new routing metrics have been proposed such as WCETT, MIC, iAWARE, EETT, and NBLC. These metrics distribute the data traffic load among channels and/or radios to reach the final destination. In this paper, we provide a qualitative comparison study that considers the characteristics of these metrics and a simulation-based performance analysis to identify the appropriate use cases of each one of them. For example, iAWARE is found to be more appropriate when there are lot of changes in interfering traffic, however WCETT and EETT are more efficient for low traffic in large networks configurations. View full abstract»

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