[show abstract][hide abstract] ABSTRACT: The networking of sensing devices has fuelled the development of a great variety of applications which lead to the wide deployment of Wireless Sensor Networks. Nowadays, as the sensor population becomes constantly denser, the exploitation of the vastly installed WSN infrastructure to feed with data additional applications is pursued. The research community currently designs architectures and protocol that virtualise the service and resources of the available sensors, which can belong to different administrative domains and can be of different technologies. The aim is to allow different applications to use/share the same WSN infrastructure, improving efficiency. In this paper, we review the virtualization attempts witnessed so far and we discuss how virtualisation assists the development of novel smart applications targeting an enhanced user experience.
WSEAS 17th International Conference on Communications (part of CSCC ’13), Rhodes, Greece; 07/2013
[show abstract][hide abstract] ABSTRACT: As the applications of wireless sensor networks proliferate, the efficiency in supporting large sensor networks and offering security guarantees becomes an important requirement in the design of the relevant networking protocols. Geographical routing has been proven to efficiently cope with large network dimensions while trust management schemes have been shown to assist in defending against routing attacks. Once trust information is available for all network nodes, the routing decisions can take it into account, i.e. routing can be based on both location and trust attributes. In this paper, we investigate different ways to incorporate trust in location-based routing schemes and we propose a novel way of balancing trust and location information. Computer simulations show that the proposed routing rule exhibits excellent performance in terms of delivery ratio, latency time and path optimality.
Wireless Communications and Mobile Computing 01/2010; · 0.86 Impact Factor
[show abstract][hide abstract] ABSTRACT: Security is currently a weak point of wireless sensor networks (WSN) impeding their proliferation although they offer flexible and low cost solutions for many every-day life applications. In WNSs, routing of data from the sensor nodes towards the destination/base station relies on the cooperation among neighbouring nodes. The realization of a trust management system which allows each node to define a trust value for each neighbour has been proposed as a powerful tool towards defending against the routing attacks. In this paper, we investigate how the trust information can be incorporated in the routing protocol and we compare based on simulation results three different trust-aware geographical routing algorithms.
[show abstract][hide abstract] ABSTRACT: It is increasingly recognized that the Internet is transforming into a platform providing services beyond todaypsilas expectations. To successfully realize this transformation, the structural limitations of current networking architectures must be raised so that information transport infrastructure gracefully evolves to address transparent core-access integration, optical flow/packet transport, and end-to-end service delivery capability, overcoming the limitations of segmentation between access, metro, and core networks and domains. We propose and evaluate an integrated control plane for optical access and core networks, which addresses the above consideration. The proposed control plane can lead to a unified transport infrastructure integrating state-of-the-art components and technologies including wavelength division multiplexing, passive optical networking, and optical packet routers with inherent traffic grooming capabilities. The performance of the proposed architecture is assessed by means of simulation in terms of cost, resource utilization, and delay.
Journal of Optical Communications and Networking 08/2009; · 1.43 Impact Factor
[show abstract][hide abstract] ABSTRACT: As Wireless Sensor Network-based solutions are proliferating they are facing new challenges: they must be capable of adapting to rapidly changing environments and requirements while their nodes should have low power consumption as they usually run on batteries. Moreover, the security aspect is crucial since they frequently transmit and process very sensitive data, while it is important to be able to support real-time video or processed images over their limited bandwidth links. SMART targets to design and implement a highly reconfigurable Wireless Visual Sensor Node (WVSN) defined as a miniaturized, light-weight, secure, low-cost, battery powered sensing device, enriched with video and data compression capabilities.
Sensor, Mesh and Ad Hoc Communications and Networks Workshops, 2009. SECON Workshops '09. 6th Annual IEEE Communications Society Conference on; 07/2009
[show abstract][hide abstract] ABSTRACT: A lot of effort has been spent in securing the routing procedure in wireless sensor network (WSNs) since this is accomplished in a cooperative way and is vital for the communication of the sensors with the base station which collects the sensed data. The communication over wireless links in combination with the ad hoc organization introduces vulnerabilities. Each node monitors the behaviour of its neighbours in order to check whether they behave maliciously or not. Nodes with low trustworthiness are then avoided during routing decisions which are based on location and trust information. The efficiency of the proposed approach in defending against black-hole, grey-hole and integrity attacks is evaluated using computer simulations.
Systems, Signals and Image Processing, 2009. IWSSIP 2009. 16th International Conference on; 07/2009
[show abstract][hide abstract] ABSTRACT: The evolution towards packet-based access networks and the importance of quality of experience brings the need for access networks that support the offer of a wide range of multimedia services not currently available to the desired extent. Legacy networks based on circuit switching used explicit signalling that travelled to all nodes along the path to book resources before the launce of the media stream. This approach does not scale well and is not in line with the philosophy of packet networks. Still, the need to reserve resources in advance remains since real-time services have limited if any means of adjusting their rates to the prevailing network conditions and to preserve customer satisfaction the traditional preventive approach that needs accurate estimates of resource needs for the duration of the session is the only option. The paper describes a possible CAC solution based on measuring flows and enriches the network with implicit admission control (without obviating explicit control if available) and can manage resource allocation to protect quality-demanding services from degradation. The basis is a flow measurement system, which will estimate the traffic load produced by the flow and activate admission control. However, because in most cases these initial indication may well be misleading, it will be cross checked against a database of previously recorded flows per customer interface which can provide long term data on the flows leaving only a few cases that have to be corrected on the fly. The overall product is a self-learning autonomic system that supports QoS in the access network for services that do not communicate with the network layer such as, for example, peer-to-peer real-time multimedia applications.
[show abstract][hide abstract] ABSTRACT: Ad-hoc wireless sensor networks (AWSN) are quickly gaining popularity due to the fact that they are potentially low-cost solutions that can be used in a variety of application areas including emergency response, medical monitoring, homeland security and environmental monitoring. On the other hand, AWSN introduce severe node resource constraints due to their lack of data storage capabilities, power limitation, low bandwidth, restricted transmission range. All these factors represent major obstacles to the implementation of traditional security techniques in AWSN. In this paper, we present AWSN security and operational requirements, sensor node constraints affecting security requirements and finally the goals of AWISSENET, an EU funded project aiming at further securing AWSN.
ELMAR, 2008. 50th International Symposium; 10/2008
[show abstract][hide abstract] ABSTRACT: The range of applications of wireless sensor networks is so wide that it tends to invade our every-day life. In the future, a sensor network will surveil our health, our home, the roads we follow, the office or the industry we work in, or even the aircrafts we use, in an attempt to enhance our safety. However, the wireless sensor networks themselves are prone to security attacks. The list of security attack is already very long and will impede the deployment of these solutions, if not efficiently addressed. In this paper, we focus on the security threats against routing, which is a basic networking service, required for any sensor network communication. Preventing the integrity and data freshness of the exchanged packets is a requirement but is not enough to secure the routing procedure. It is required to set-up a trust management scheme which allows the nodes to select trusted paths rather than secure routes in the network by observing the sincerity in participation by other nodes. A trust management system can be useful for detecting a node which is not behaving as expected (either faulty or maliciously). Current trends in trusted routing for ad-hoc networks are reviewed, followed by comments on their applicability in sensor network and guidelines for trust model design for new sensor applications.
ELMAR, 2008. 50th International Symposium; 10/2008
[show abstract][hide abstract] ABSTRACT: Wireless Sensor Networks (WSN) are quickly gaining popularity due to the fact that they are potentially low‐cost solutions that can be used in a variety of application areas including emergency response, medical monitoring, homeland security and environmental monitoring. However, due to their wireless nature, the relevant security requirements form a quite extensive list. An important subset of their security threats can be addressed implementing a trust management system, which establishes trust relationships among the network nodes. The methods for calculating trust via concatenation and multipath propagation are referred to as trust models. For a complete estimation of such a scheme not only computational complexity, but also the level of increase of the total network throughput and the impact on energy consumption must be thoroughly examined in order to evaluate its effective applicability in AWSN networks.
[show abstract][hide abstract] ABSTRACT: The primary requirements of a successful wireless sensor network security architecture are confidentiality, integrity and authentication. Most of these security objectives can be addressed using appropriate hash functions and cryptography schemes. By applying these mechanisms, the energy consumption increases, shortening the sensor node lifetime. On the other hand, the selection of a highly secure encryption algorithm might lead to unacceptable computational time, taking into account the constrained processor power of the sensor nodes. This paper presents an overview of the results published in the literature regarding time and energy consumption overhead of hashing and encryption mechanisms in wireless sensor networks. The evaluation of these results helps on the selection of the appropriate algorithms, depending on the application.
Systems, Signals and Image Processing, 2008. IWSSIP 2008. 15th International Conference on; 07/2008
[show abstract][hide abstract] ABSTRACT: Todaypsilas core networks deploy wavelength division multiplexing (WDM) to offer high capacity of the order of 1 Tb/sec and long reach transmission of the order of 1000 km. In such systems, the information is transmitted optically on different wavelengths but it is transferred across the network through fibre links that are terminated by SONET/SDH equipment. In such networks, layer crossing is inevitable, requiring deep data inspection and complex protocol processing, resulting in limited scalability and high installation, operation and maintenance cost. It is however the only reliable end-to-end service delivery scenario available today that utilises the optical bandwidth and guarantees provisioning of resources. In this paper we review the alternative concept of CANON (clustered architecture for nodes in optical networks), a scenario that utilises clustering of nodes in ring topologies to create a hierarchy in transporting traffic in a dynamic, future proof and scalable manner. Here we emphasize on the optical crossconnect architectures that can serve such a network scenario.
[show abstract][hide abstract] ABSTRACT: The explosion of current demand has brought the contemporary multidomain core network paradigm to its limit. In the quest for new approaches that exploit recent developments in optical technology, a novel network architecture that obviates most of the expensive and loss-prone centralized all-optical switches is described in this work. It is based on clustered architecture for nodes in optical networks and features a reconciliation between dynamic resource allocation and guaranteed end-to-end network performance in a multidomain network. This article enhances the distributed, collision-free slot aggregation inside domains of clustered core nodes with dynamic switching of slots/frames between the domains. Thus, it can support dynamic sub-wavelength allocations between network domains, using standard burst-switching techniques. This extends the high efficiency and multiplexing gain into the inter-domain network even under highly bursty traffic. It features both low-cost optical add/drop edge nodes exploiting WDM transmission and agile and modular centralized electro-optical switches that are presented in conjunction with the overall network architecture. Its performance exhibits very low burst loss probability traded for a higher but tolerable and bounded delay.
[show abstract][hide abstract] ABSTRACT: Optical Burst Switching achieves multiplexing gain in the optical domain but cannot reach reasonable utilization before burst losses become unacceptable. In this paper, we analytically evaluate a novel method to avoid these losses by first sending over the control channel a short scout packet that simulates the events that the actual packet will experience. Once the scout message detects a drop at any of the intermediate nodes, the actual packet is not sent but the process repeated. The penalty is the delay for the implicit reservations and the occasional process repetition, limiting the applicability of this approach to a periphery of no more than just few thousand kilometers. A slotted approach is adopted to facilitate accounting of data and allow for pipelined operation which improves performance. We also evaluate the implementation complexity of the proposed scheme to prove its feasibility and the avoidance of congestion on the control channel.
[show abstract][hide abstract] ABSTRACT: The novel core network architecture presented in this paper realizes distributed all-optical switching of payload by partitioning the network into a number of geographically limited domains, where two-way reservations are effective. Thus, inside each domain, loss is eliminated, while traffic from many nodes can be aggregated into single bursts, improving efficiency. Clustered nodes contribute contiguous optical slots, which are marshaled into composite optical frames destined for other clusters, under the guidance of a reservation-based control protocol. The lossless aggregation of traffic from several core nodes allows the use of cost-effective bufferless all-optical transport among the domains with electrical buffers employed at the periphery of the system. The end result is a triple improvement in loss probabilities, efficiency, and cost. This is achieved by exploiting three features of the architecture: the distributed switching functionality (as in early LANs when centralized switching was expensive), localized reservations (avoiding the intolerable delays of end-to-end reservations), and a reduced number of source-destination pairs (by means of node clustering into reservation domains)
Journal of Lightwave Technology 06/2007; · 2.56 Impact Factor
[show abstract][hide abstract] ABSTRACT: We propose and evaluate a resource allocation scheme for time-division multiplexing passive optical networks (PONs), which supports multiple service classes; dynamic bandwidth allocation for services with varying (in time) capacity demand; and bounded quality of service parameters for services with real-time requirements. Although several algorithms have been proposed in the literature considering several of the above objectives in isolation, our work focuses on the fundamental problem of trading-off between PON upstream channel utilization and strict delay and jitter bounds when supporting a dynamically changing mix of services with different requirements.
Journal of Optical Networking 01/2007; 6(7). · 1.08 Impact Factor
[show abstract][hide abstract] ABSTRACT: Since the emergence of Ethernet PONs (EPONs) several mechanisms have been proposed aiming to enhance the performance of traffic multiplexing and upstream channel arbitration. Efficient resource utilization should feature several properties including among others support for multiple service classes, Dynamic Bandwidth Allocation (DBA) for services with varying (in time) capacity demand and bounded QoS parameters for services with real-time requirements. In this paper we propose a new mechanism which presents the above features and targets an optimal trade-off between EPON upstream channel utilization and strict delay and jitter bounds for real time traffic.
Photonics in Switching, 2006. PS '06. International Conference on; 11/2006
[show abstract][hide abstract] ABSTRACT: Optical burst switching achieves multiplexing gain in the optical domain but cannot reach reasonable utilization before burst losses become unacceptable. A method to avoid these losses by first sending over the control channel a short scout packet that simulates the events that the actual packet will experience, is proposed in this paper. Once the scout message detects a drop at any of the intermediate nodes, the actual packet is not sent but the process repeated.
Photonics in Switching, 2006. PS '06. International Conference on; 11/2006
[show abstract][hide abstract] ABSTRACT: Clustering neighboring nodes of an all-optical core network into medium-sized rings featuring reservation-based control, allows lossless aggregation of bursts and a reduction of possible source-destination pairs. Both act towards reducing the system cost and burst loss creating an architecture that obviates most of the expensive and loss-prone all-optical switches by delegating the switching function to a medium access control protocol coordinating the distributed laser transmitters. This is in principle the approach taken in early LANs, but with the optical switches the incentive is not limited to avoiding their high cost but also the high burst loss arising from the very limited optical buffering. The end result is a core architecture with much lower losses than one-way systems, much lower delay than solutions employing two-way reservations end-to-end, still achieving multiplexing gain.
Photonics in Switching, 2006. PS '06. International Conference on; 11/2006
[show abstract][hide abstract] ABSTRACT: Optical burst switching is a core architecture designed to reconcile the available optical technology with the increasing burstiness of traffic. However, disappointing performance in terms of high packet loss and/or low system utilization discouraged broader experimental implementations. A method to avoid these losses by first sending over the control channel a short scout packet that simulates the events that the actual burst will experience is proposed in this paper. Once the scout message detects a drop at any intermediate node, it returns back to the source to avert the payload emission and repeat the process. The way the control works results in essential service quality features, i.e., no loss of bursts, no out-of-order emissions, increased efficiency, much reduced delay variation, and graceful throttling of the load respecting the contracted rates.
Journal of Lightwave Technology 11/2006; 24(10):3616-3624. · 2.56 Impact Factor