Protection and performance are the major requirements for any Intrusion Detection and/or Prevention System (IDPS). Existing IDPSs do not seem to provide a satisfactory method of achieving these two conflicting goals. Intrusion Detection Systems (IDSs) fulfill the network performance requirement but exhibit poor protection under successive attacks. On the other hand, Intrusion Prevention Systems (IPSs) can protect the network by dropping the malicious packets that match any attacking pattern; however, this can have a negative impact on network performance in terms of delay as the attacking patterns increase. This results in a tradeoff between security enforcement levels on one hand and the performance and usability of an enterprise information system on the other. This paper aims to study the impact of security enforcement levels on the performance and usability of an enterprise information system. We propose a rule mode selection optimization technique that aims to determine an appropriate IDPS configuration set in order to maximize the security enforcement levels while avoiding any unnecessary network performance degradation. Simulation was conducted to validate our proposed technique. The results demonstrate that it is desirable to strike a balance between system security and network performance.

In this paper, we propose a new Compression Cluster-based scheme in a Spatial Correlated Region (CC_SCR) for event-driven applications in wireless sensor networks. The main idea behind our proposal is to exploit the spatial correlation of such networks in order to reduce the size of the data packets that will be sent by means of data compression. The proposed clustering scheme is based on selecting a data value as reference while the rest of the active nodes transmit only the difference between their sensed value and this reference value. Hence, one major issue in the proposed mechanism is to appropriate select the reference node that achieves the highest reduction of the packet size among all active nodes. The CC_SCR protocol is evaluated by simulations. The results show that CC_SCR may reduce as much as 11 times the energy consumption compared to a classical clustering scheme.

Intrusion Detection and/or Prevention Systems (IDPS) represent an important line of defense against a variety of attacks that can compromise the security and proper functioning of an enterprise information system. Although many IDPS systems have been proposed, their appropriate configuration and control for effective attacks detection/prevention and efficient resources consumption has always been challenging. The evaluation of the IDPS performance for any given security configuration is a crucial step for improving real-time capability. This paper aims to analyze the impact of security enforcement levels on the performance and usability of an enterprise information system. We develop a new analytical model to investigate the relationship between the IDPS performance and the rules mode selection. In particular, we analyze the IDPS rule-checking process along with its consequent action (i.e., alert or drop) on the resulting security of the network, and on the average service time per event. Simulation was conducted to validate our performance analysis study. Our results show that applying different sets of rules categories and configuration parameters impacts average service time and affects system security. The results demonstrate that it is desirable to strike a balance between system security and network performance.

Cognitive radio presents a new approach to wireless spectrum utilization and management. In this work, the potential performance improvement gained by applying cognitive radio to wireless mesh networks is investigated. Specifically, the potential benefits in terms of QoS provided to users and the efficiency of resource utilization are quantified in a system consisting of a collection of one or more service provider wireless networks. To achieve this, we formulate the problem mathematically using integer linear programming. It is shown that the cognitive radio abilities provide an advantage over the classical network, either by improving QoS through increasing the probability of accepting connection requests, or by reducing the resources needed to fulfill the QoS requirements of users. This advantage is gained without impacting the service of primary clients. More importantly, we show that virtual wireless networks can be created, utilizing only the residual wasted bandwidth of the primary service providers. These virtual networks are able to support large volumes of users, while still ensuring that QoS reliability requirements, such as acceptance probability guarantees, are achieved.

In this paper, we address the radio resource utilization efficiency in single channel wireless mesh networks (WMNs) while considering the mobility of users and when multiple simultaneous connections on the same channel exist in the network. To achieve this, we use clustering. We first identify through analytical models and simulations the cases where clustering is helpful. Building on these results, we propose two clustering schemes that take into consideration the mobility properties of users in order to improve the WMN performance. We prove that both schemes can achieve significant gains in terms of radio resource utilization, especially when the number of simultaneous connections in the network increases. Specifically, we show that the first scheme fits better low-connected wireless mesh networks, whereas the second scheme is more suitable for highly-connected networks.

Diversified opportunities (possible numerous applications) and challenges (resource constrained nodes) are contributing factors behind the extensive research in sensor networks. Continuous monitoring of the natural phenomenon is one of the major streams of the possible application in this arena. Sensing and monitoring of natural phenomenon involve dealing with correlated data in both spatial and temporal dimension. Aggregation technique plays a significant role by reducing the amount of data transmission in wireless sensor networks (WSN)as correlation is dominating in the real world. This reduction on the amount of data is vital due to the energy scarcity of the WSN. This paper presents a simple aggregation technique named smart aggregation (SAG) for the continuous-monitoring applications in WSNs. SAG maintains a tolerable deviation i.e. limited error in the aggregated data while compressing both spatially and temporarily. We present simulated results that rationalize the development of the protocol. The comparison is made with k-hop aggregation and CM-EDR algorithm in terms of energy efficiency showing the potential improvement gained by applying our aggregation scheme.

This paper presents a new metric for routing in wireless mesh networks (WMNs). The proposed metric does not only consider the quality of wireless links to choose a high throughput path between a pair of nodes, but it also includes the resulting interference introduced by using such links. The philosophy behind this metric is to choose a good path for an arriving connection, not necessarily the best in terms of throughput, but that alleviates the resulting interference in order to preserve good paths for the subsequent arriving connections. In doing so, we find that our metric significantly outperforms previously proposed routing metrics when multiple concurrent flows are considered in the network. The total network throughput is indeed increased.

One of the major concerns in wireless mesh networks (WMNs) is the radio resource utilization efficiency, which can be enhanced by efficiently managing the mobility of users. To achieve this, we propose in this paper the use of mobility-aware clustering. The main idea behind WMN clustering is to restrict a major part of the exchanged signaling messages due to the mobility of users to a local area (i.e., inside a cluster). As such, less wireless links are used by the signaling messages, which reduces the resources occupied by a mobile user during its service and thus improves the total network capacity. Through analytical models and simulations, this work first identifies the cases where clustering is helpful. Building on these results, we propose two clustering schemes that take into consideration the mobility properties of the users in order to improve the WMN performance. We prove that both schemes can achieve significant gains in terms of radio resource utilization. Specifically, we show that the first scheme fits better both large and low-connected wireless mesh networks, whereas the second scheme is more suitable for both small to moderate and highly connected networks.

Wireless Sensor Networks (WSNs) can be typically used to achieve Continuous Monitoring (CM) or Event-Detection inside the supervised area. In CM applications each sensor node transmits periodically its sensed data to the sink node while in Event-Detection Driven (EDD) applications, once an event occurs, it is reported to the sink node by the sensors within the event area. Applications using both continuous monitoring and event driven reporting can also be considered. In this paper, we investigate such hybrid WSNs. Specifically, we propose to reduce the energy consumption by grouping the nodes that sense an event into a separate cluster. By doing so, as it is shown in this paper, the efficiency of the data compression scheme is indeed improved. This event-aware clustering scheme is compared to the case where the event data is transmitted through already established clusters. Finally, the case where sensor nodes only transmit information whenever they sense relevant data is introduced in order to achieve further energy savings.

Wireless sensor networks (WSNs) require energy- efficient protocols to improve the network lifetime. In this work, we adopt a cross-layer strategy that considers routing and MAC layers jointly. At the routing layer, we propose balancing the traffic through the WSN. We show that sending the traffic generated by each sensor node through multiple paths instead of using a single path allows significant energy conservation. On the other hand, at the MAC layer, we propose to control the retry limit of retransmissions over each wireless link. We show that by efficiently adjusting the retry limit for each link, further energy conservation can be achieved, improving thus the network lifetime. A new analytical model for the joint optimization system is complemented by simulations in order to quantitatively evaluate the benefits of our proposal.

Efficient mobility management is one of the major challenges for next-generation mobile systems. Indeed, a mobile node (MN) within an access network may cause excessive signaling traffic and service disruption due to frequent handoffs. The two latter effects need to be minimized to support quality of service (QoS) requirements of emerging multimedia applications. In this paper, we propose a new adaptive micromobility management scheme designed to track efficiently the mobility of nodes so as to minimize both handoff latency and total signaling cost while ensuring the MN's QoS requirements. We introduce the concept of residing area. Accordingly, the micromobility domain is divided into virtual residing areas where the MN limits its signaling exchanges within this local region instead of communicating with the relatively far away root of the domain at each handoff occurrence. A key distinguishing feature of our solution is its adaptive nature since the virtual residing areas are constructed according to the current network state and the QoS constraints. To evaluate the efficiency of our proposal, we compare our scheme with existing solutions using both analytical and simulation approaches for the 2-D random walk model as well as real mobility patterns. Numerical and simulation results show that our proposed scheme can significantly reduce registration updates and link usage costs and provide low handoff latency and packet loss rate under various scenarios.

Energy conservation is a primary concern in wireless sensor networks due to the limited capacity of the sensor nodes' batteries. In this paper, we study the relationship between sensor networks performance, particularly its lifetime, and the number of reporting nodes N by using both analytical and simulation approaches. We first show that decreasing N increases considerably the network lifetime. Moreover, we demonstrate that the average time required to report an event is a convex function of N. Based on these results, and as a main contribution, we prove that the optimal number of reporting nodes enabling the shortest latency to report reliably an event does not really lead to the most efficient way of energy consumption. In this paper, we analyze the tradeoff between these two requirements. We provide a simple methodology to achieve this tradeoff which is specific to each sensor application, depending on its particular needs.

Wireless sensor networks (WSNs) require appropriate protocols that make judicious use of the finite energy resources of the sensor nodes. In this paper, we investigate the potential energy conservation achieved by balancing the traffic throughout the WSN. We show that distributing the traffic generated by each sensor node through multiple paths instead of using a single path allows significant energy savings. In order to quantitatively evaluate the benefits of the proposed load balancing technique, a new analytical model for load-balanced systems is elaborated and approved by simulations.

Energy-efficiency is one of the major concerns in wireless sensor networks since it impacts the network lifetime. In this paper, we investigate the relationship between sensor network performance, particularly its lifetime, and the number of active reporting nodes N by using both analytical and simulation approaches. We first demonstrate that decreasing the number of reporting nodes increases the number of reports that need to be sent to the sink, in order to achieve the desired information reliability regarding the detected event. On the other hand, we show that reducing the number of reporting nodes alleviates the energy wastage due to collisions. Based on this tradeoff, and as a main contribution, we derive the optimal number of reporting nodes Nopt.energythat minimizes the energy consumed to report reliably the occurrence of an event. In other words, we prove that limiting the reporting tasks of a detected event to a small subset of sensor nodes (i.e., Nopt.energy), instead of using all the sensor nodes in the event area, enables significant energy conservation.

Cognitive radio presents a new approach to wireless spectrum utilization and management. In this work, the potential performance improvement gained by applying cognitive radio to multiple-provider wireless systems is investigated. It is shown that virtual wireless networks can be created, utilizing only the residual wasted bandwidth of the primary service providers. These virtual networks are able to support large volumes of users, while still ensuring that QoS reliability requirements, such as blocking and dropping guarantees, are achieved. A Markov chain-based analysis of classic and cognitive systems is complemented by simulations in order to present a quantified perspective of the potential benefits of cognitive radio techniques.

Energy conservation is a primary concern in wireless sensor networks due to the limited capacity of the sensor nodes' batteries. In this paper, we study the relationship between sensor networks performance, particularly its lifetime, and the number of reporting nodes N by using both analytical and simulation approaches. We first show that decreasing N increases considerably the network lifetime. Moreover, we demonstrate that the average time required to report an event is a convex function of N. Based on these results, and as a main contribution, we prove that the optimal number of reporting nodes enabling the shortest latency to report reliably an event does not really lead to the most efficient way of energy consumption. In this paper, we analyze the tradeoff between these two requirements. We provide a simple methodology to achieve this tradeoff which is specific to each sensor application, depending on its particular needs.

Energy-efficiency is one of the major concerns in wireless sensor networks since it impacts the network lifetime. In this paper, we investigate the relationship between sensor network performance, particularly its lifetime, and the number of active reporting nodes N by using both analytical and simulation approaches. We first demonstrate that decreasing the number of reporting nodes increases the number of reports that need to be sent to the sink in order to achieve the desired information reliability regarding a detected event. On an other side, we show that reducing the number of reporting nodes reduces the probability of collision occurrence. Based on these results, and as a first main contribution, we derive the optimal number of reporting nodes Nopt_energy that minimizes the energy consumed to report reliably the occurrence of an event. In other words, we prove that limiting the reporting tasks of a detected event to a small subset of sensor nodes (i.e., Nopt_energy), instead of using all the sensor nodes in the event area, enables significant energy conservation.

Energy-efficiency is one of the major concerns in wireless sensor networks since it impacts the network lifetime. In this paper, we investigate the relationship between sensor networks performance, particularly its lifetime, and the number of reporting nodes N by using both analytical and simulation approaches. We first show that the network lifetime and the number of correctly received reports increase when N decreases. Moreover, we demonstrate that the average time required to report an event is a convex function of N. Based on these results, and as the main contribution, we prove that the optimal number of reporting nodes minimizing the energy consumption in the network does not correspond to the optimal number of reporting nodes allowing the fastest way to report an event. The tradeoff between these two requirements is therefore specific to each sensor application, depending on its particular needs. In this paper, we provide a simple methodology to achieve this tradeoff.

In this paper, we propose a new adaptive MPLS-enabled micro-mobility management scheme designed to track efficiently the mobility of nodes so as to minimize both handoff latency and total signaling cost while ensuring the mobile node's QoS requirements. To achieve this, we introduce a new concept called residing area. Accordingly, the micro-mobility domain is divided into virtual residing areas where the MN limits its signaling exchanges within this local region instead of communicating with the relatively far away root of the domain at each handoff occurrence. One of the key distinguishing features of our solution from existing literature is its adaptive nature since the virtual residing areas are constructed according to the current network state and the QoS constraints. To evaluate the efficiency of our proposal, we compare our scheme with existing solutions using both analytical and simulation approaches. Numerical and simulation results show that our proposed scheme can significantly reduce registration updates and link usage costs and provide low handoff latency under various scenarios.

In this paper, we propose a new solution to cope with the unfairness limitations of the distributed coordination function (DCF) algorithm. Our solution is based on multiple backoff windows principle. We demonstrate through simulations the efficiency of our proposal that enables fair bandwidth sharing and increase total network throughput.

One the of major challenges of optical network operators is ensuring the stringent levels of availability required by their highest class clients. To achieve this, we introduce relative priorities among the different primary connections contending for access to the shared-protection paths. In this paper, we provide an analytical model for the proposed priority-enabled scheme. As a key distinguishing feature from existing literature, we derive explicit analytic expressions for average the availability and service disruption rate for the different priority classes.

International audience

One of the major challenges for the wireless networks is related to efficient mobility management issue. In this paper, we propose a new micro-mobility management scheme, called Micro Mobile MPLS, that supports both mobility and quality-of-service (QoS) management in cellular networks. Our proposal includes two protocol variants. In the first variant, called FC-Micro Mobile MPLS, the forwarding chain (FC) concept is provided to track efficiently the host mobility within a domain. This concept fits mobile nodes (MNs) with high mobility rate. The second protocol variant, called Master Forwarding Chain (MFC)-Micro Mobile MPLS, aims to reduce the total signaling cost by controlling the number of registration updates with the root of the domain. In order to assess the efficiency of our proposals, the aforesaid protocols are compared with respect to the existing solutions. To achieve this, we develop analytical models to evaluate both registration updates and link usage costs. Numerical and simulation results show that the proposed mechanisms can significantly reduce the registration updates cost and provide low handoff latency and packet loss rate under various scenarios.

In this paper, we study a new concept of traffic grooming in wavelength-division multiplexing (WDM) ring networks that aims at eliminating both the bandwidth underutilization and the scalability concerns that are typical of all-optical wavelength-routed ring networks. Our objective is to reduce the network cost while preserving the benefits of alloptical WDM ring networks. In order to assess the efficiency of our proposal, all underlying network costs are compared. These costs include that of the transceivers required at node level, as well as the number of wavelengths. Our results show that the proposed aggregation technique can significantly improve the resource utilization while reducing the network cost.

In this paper, we propose an analytical approach to study the handoff performance of a wireless system with a new micro-mobility support called Micro Mobile MPLS. Our scheme includes two protocol variants. First, the fast handoff process, which anticipates the LSP procedure setup with an adjacent neighbor subnet that an mobile node (MN) is likely to visit, is provided to reduce service disruption. Second, a new mechanism based on the forwarding chain concept is proposed to track efficiently the host mobility whithin a domain. This concept can significantly reduce the registration updates cost and provide low handoff latency and packet loss rate. Analytical models, which capture the mobility behavior of an MN, are developed for cost analysis. Numerical and simulation results are given to justify the benefits of our proposed mechanisms.

Multi-protocol label switching (MPLS) is deployed in the Internet backbone to support service differentiation and traffic engineering. In recent years, there has been an interest to extend the MPLS capability to the wireless access networks for mobility management support. In this paper, we present an analytical approach to study the handoff performance of a wireless system with a new micro-mobility support called micro mobile MPLS. Our scheme includes two protocol variants. In the first variant called FH-micro mobile MPLS, we consider the fast handoff mechanism, which anticipates the LSP procedure setup with an adjacent neighbor subnet that an mobile node (MN) is likely to visit. This mechanism is proposed to reduce service disruption by using the link-layer (L2) functionalities. In the second variant called FC-micro mobile MPLS, the forwarding chain concept, which is a set of forwarding path, is provided to track efficiently the host mobility within a domain. This concept can significantly reduce the resource reservation cost, the registration updates cost and provide low handoff latency. Analytical models, which capture the mobility behavior of an MN, are developed for cost analysis. Numerical and simulation results are given to justify the benefits of our proposed mechanisms

One of the major challenges for the wireless networks is related to efficient mobility management issue. In this paper, we propose a new micro-mobility management scheme, called micro mobile MPLS, that supports both mobility and quality-of-service (QoS) management in cellular networks. Our proposal includes two protocol variants. In the first variant, called FC-micro mobile MPLS, the forwarding chain (FC) concept is provided to track efficiently the host mobility within a domain. This concept fits mobile nodes (MNs) with high mobility rate. The second protocol variant, called master forwarding chain (MFC)-micro mobile MPLS, aims to reduce the total signaling cost by controlling the number of registration updates with the root of the domain. In order to assess the efficiency of our proposals, all underlying protocols are compared through simulations using both two-dimensional (2-D) and one-dimensional (1-D) mobility models. Simulation results show that our proposed mechanisms can significantly reduce the registration updates cost and provide low handoff latency and packet loss rate under various scenarios

In this paper, we propose a practical approach to address how micro-mobility can be provided in an efficient way with continuous quality of service (QoS) support. Our proposal is based on multiprotocol label switching (MPLS) and mobile IP and relies on two-level hierarchy architecture. It supports two protocol variants. First, the fast handoff process, which anticipates the LSP procedure setup with an adjacent neighbor subnet that a mobile node (MN) is likely to visit, is provided to reduce service disruption. Second, a new mechanism based on a master forwarding chain concept is proposed to track efficiently the host mobility within a domain. Our concept can significantly reduce the total signaling cost and provide low handoff latency. This can be achieved by dynamically controlling the number of registration updates with the root of the domain according to a cost comparison. Analytical models are developed and simulations are conducted to justify the benefits of our proposed mechanisms

In this paper, we propose and evaluate a new concept of traffic aggregation in wavelength-division multiplexing (WDM) optical networks that aims at eliminating both the bandwidth underutilization and the scalability concerns that are typical of all-optical wavelength-routed networks. Our objective is to reduce the network cost while preserving the benefits of all-optical wavelength-routed networks. In order to assess the efficiency of our proposal, all underlying network costs are compared. These costs include that of the transceivers and cross-connect ports required at node level, as well as the number of wavelengths. Our results show that the proposed aggregation technique can significantly reduce the network cost

One of the main concerns in wireless sensor networks is improving the network lifetime. The basic idea underlying current studies is the partial utilization of the sensor network resources. Nevertheless, most of the existing works focus on the connection upholding issue, while neglecting the coverage problem. Therefore, we investigate, in this paper, the relationship between the network lifetime and the coverage problem. We show that controlling the density function, relying on efficient sensor nodes placement, can improve significantly network lifetime. In this regard, we propose an efficient placement algorithm addressing the case where the monitored area density is equal to two. Afterwards, we extend the algorithm dealing with the case where the terrain density is higher than two. Finally, we gauge the efficiency of our proposal through analytical models and simulations.

In this paper, we propose a practical approach to address how micro-mobility can be provided in an efficient way with continuous quality of service (QoS) support. Our proposal is based on multiprotocol label switching (MPLS) and mobile IP and relies on two-level hierarchy architecture. It supports two protocol variants. First, the fast handoff process, which anticipates the LSPs procedure setup with the neighboring locations where a mobile node (MN) may move to, is provided to reduce the service disruption. Second, a new mechanism based on the forwarding chain concept is proposed to track efficiently the host mobility within a domain. This concept can significantly reduce the registration updates cost and provide low handoff latency. Analytical models are developed and simulations are conducted to justify the benefits of our proposed mechanisms

Packet-based optical access ring is becoming a promising solution in metropolitan networks. Its performance depends mainly on how optical resource sharing takes place among the different competing access nodes. This network architecture has mostly been explored with regard to synchronous transmission, i.e., slotted wavelength-division multiplexing (WDM) ring. However, in this paper, we focus on the performance of asynchronous transmission-based networks with variable packet sizes. Analytical models are presented in an attempt to provide explicit formulas that express the mean access delay of each node of the bus-based optical access network. We prove that in such a network, fairness problems are likely to arise between upstream and downstream nodes sharing a common data channel. Furthermore, we show that sharing the channel's available bandwidth fairly but arbitrarily between access nodes, as in slotted WDM rings, does not resolve the fairness problem in asynchronous system. In this regard, we exhibit the inherent limitations of the token bucket access rate-based algorithm once applied to asynchronous transmission bus-based networks. To alleviate the aforementioned problem, we device a new strategy called traffic control architecture using remote descriptors. The proposed solution is based on a preventive mechanism to grant access to the shared resource. As illustrated in this paper, the proposed solution alleviates the performance degradation and the resource underutilization, while achieving fairness among bus nodes.

In this paper, we propose and evaluate a new concept of traffic aggregation in mesh networks that aims to eliminate the bandwidth underutilization problem existing in all-optical wavelength routed networks. The proposed solution is based on the distribution of the aggregation process. So, instead of limiting the utilization of lightpaths capacity to the ingress node, each node along the path is allowed to fill on the fly this optical resource according to its availability. Therefore, the lightpath will be shared by several connections traveling from multiple ingress nodes to a single egress node. This technique combines the benefits of optical bypass and the statistical multiplexing gain. In order to gauge the value of the proposed solution, we formulate the problem using integer linear programming and study its performance through different scenarios using a prototype network. Our results show that distributed aggregation technique can improve significantly the network throughput and reduce the network cost.