Showing papers by "Helen C. Leligou published in 2008"

Analyzing energy and time overhead of security mechanisms in Wireless Sensor Networks

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.

Dynamic CANON: a scalable multidomain core network

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.

Trust models for sensor networks

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.

AWISSENET: Setting up a secure Wireless Sensor Network

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.

Next generation Ethernet access networks: GPON vs. EPON

Abstract: Recently both ITU and IEEE have standardized solutions for Passive Optical Networks operating at gigabit per second line rates and optimized for the transport of packet-based traffic to improve the efficiency of previously standardized broadband PONs, which were based on ATM. The efficiency and performance of PON systems, depends mainly on the implemented medium access protocol. The latter is not part of the standards and left to the implementer, however the standards describe a set of control fields that constitute the tool-set for the MAC operation. In this paper we compare the efficiency and performance of the two systems under as close as possible MAC.

Multi-granular optical cross-connects for the CANON network scenario

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.