Search

PUBLISHED, San Diego, USA, The network equipment cost benefit of dynamic wavelength routing is compared with point-to-point IP networks and static wavelength routing in a simple ring topology with variable network traffic loading.

PUBLISHED, Bologna, Italy, We present a policy-driven trading framework for market-based spectrum assignment. Our work allows spectrum consumers to get exclusive access rights through payment of a fee, for a given period of time, and for a given frequency band and location. The key motivation behind our proposal stems from the increased complexity of new spectrum management strategies and the need for extracting the maximum benefit from the available spectrum. In this paper we demonstrate that a policy-driven solution is applicable for the management of spectrum markets, and we present a decentralised and lightweight framework for implementing such markets in networked environments., SFI

PUBLISHED, Hybrid electro-optical architectures have been recently proposed as cost-effective solution to challenge nearfuture traffic demands. We believe that IP routing technology can be closely integrated with optical circuit switching using a multi-layer traffic engineering approach. In this paper we propose a novel network architecture that, by exploiting the flow correlation of Internet packets, redirects the traffic into dynamically created optical paths, providing optical bypass of the IP layer. The simulation results we provide are based on real traffic traces collected from the pan-European GEANT network.

PUBLISHED, Manchester, United Kingdom, Current research trends in networks and telecommunications suggest that future architectures will aim for the convergence not only of fixed and mobile infrastructures, but also of different network layer technologies. Proposals like OCALA from UC Berkeley and our own TRANSIT can be used to converge different architectures and network layer overlays while supporting legacy applications. In this paper we analyse and assess the security threats against such systems. Our contribution constitutes the first step in designing security models for convergence architectures as part of their design and deployment phases, rather than as retrofitted mechanisms, This material is based upon works supported by Science Foundation Ireland under grant number 03/CE3/I405.

PUBLISHED, This paper develops the concept of a telecommunications value-chain and explores the many ways in which the valuechain can be altered by reconfigurable software-defined radios, cognitive radios and cognitive networks. In cognitive radio terms, value creation can occur through increased functionality of devices, such as the alwaysconnected- anywhere feature of a cognitive radio for example. This value can migrate within the value-chain according the context in which the device is operating in, and the time-varying objectives of the system. However, this newly created value is not easily captured and the dynamics of value migration within the value chain are complex and difficult to manage. The design, test, manufacture, certification, maintenance and evolution of software-defined radio and cognitive radios, and the subsequent implications for the value-chain are explored. In addition, a scenario involving a network of cognitive radios and the subsequent impact on the value-chain will be investigated.

PUBLISHED, Current telecommunications systems allocate identifiers to devices, and end-points. While this has worked well thus far, we believe that as more devices are used to access these systems, people have a tendency to be mobile across these devices. In this article we review current systems and introduce a new model for telecommunications, which we term person to person communications. Under this new model people are allocated identifiers, which they may associate with any number of devices. We outline why we believe this to be a more effective model than the current one, This material is based, in part, upon works supported by Science Foundation Ireland under grant number 03/CE3/I405.(SFI)

PUBLISHED, The lack of a unified control plane does not allow current optical networks to dynamically provision new optical paths. The IETF standardization body has proposed the generalized multi-protocol label switching standard as a solution to this problem. Their efforts however focus on the creation of end-to-end optical trails. This concept is convenient for major service providers, whose network may span a large area, but may not suit smaller network operators. We believe that the future trend of the telecommunication industry is made up of a global network formed by many inter-linked operators of small and medium size. A novel type of network based on a distributed and disaggregated architecture seems to be the best solution to dynamic optical path establishment. In this paper we present an optical testbed implementing the concept of optical IP switching. Central to the system is the optical router that creates new lightpaths depending on encountered traffic flows. The decision making process is completely distributed, and perfectly fits the disaggregated network view. The testbed currently links two universities in Dublin, and may in future be extended to join other existing research networks., SFI

PUBLISHED, In this article we present a survey of secure ad hoc routing protocols for mobile wireless networks. A mobile ad hoc network is a collection of nodes that is connected through a wireless medium forming rapidly changing topologies. The widely accepted existing routing protocols designed to accommodate the needs of such self-organized networks do not address possible threats aiming at the disruption of the protocol itself. The assumption of a trusted environment is not one that can be realistically expected; hence, several efforts have been made toward the design of a secure and robust routing protocol for ad hoc networks. We briefly present the most popular protocols that follow the table-driven and the source-initiated on-demand approaches. Based on this discussion we then formulate the threat model for ad hoc routing and present several specific attacks that can target the operation of a protocol. In order to analyze the proposed secure ad hoc routing protocols in a structured way we have classified them into five categories: solutions based on asymmetric cryptography; solutions based on symmetric cryptography; hybrid solutions; reputation-based solutions; and a category of add-on mechanisms that satisfy specific security requirements. A comparison between these solutions can provide the basis for future research in this rapidly evolving area.

PUBLISHED, Pervasive computing environments have by definition three main inherent properties; extremely open and dynamic nature, suggesting large number of interactions among previously unknown entities, the ability to adapt according to perceived context information, and interaction interfaces that integrate naturally with the goals users are trying to achieve. Traditional security management approaches fail to capture the requirements of pervasive computing. Our proposed architecture, called ?THER, addresses access control and the establishment of security associations in pervasive environments by extending traditional trust management.We model permissions as the rights of authority sets that grow dynamically without requiring manual reconfigguration, and we definne context-adaptive access control policies that are embedded into pervasive artifacts using the well defined concept of location-limited channels.

PUBLISHED, SFI

PUBLISHED, Monterey, Cailfornia, Software radio promises tremendous benefits from both commercial and military standpoints. Currently, there are a number of different 'shades' of software radio based on the use of FPGAs, DSP chips or general-purpose processors to perform the signal processing. There are also hybrids between these three platforms. The Network and Telecommunications Research Group (NTRG) approach is to focus on the use of a general-purpose processor (GPP). This maximizes the reconfigurability of the system. The use of a GPP to perform signal processing for communications applications presents the developer with challenges but it also presents some opportunities. We argue new classes of algorithms are required which will exploit the advantages and negate the disadvantages of using a GPP. Indeed other researchers have already started this programme of 'algorithmic advances'. This paper discusses the issues involved and reviews some existing developments. We present our own progress in developing a noise adaptive symbol synchroniser.

PUBLISHED, The combination of real-time message delivery and presence awareness has to lead the rapid rise in popularity of Instant Messaging (IM) in recent years. The extension of IM to mobile ad-hoc networks certainly offers considerable potential. However, the dynamic topology and decentralized nature of these networks requires several major issues to be addressed. Specifically, difficulties exist in providing an effective reliable service in the absence of a continuously available server. We present here the Dawn IM system, which takes a decentralized approach to bringing the functionality inherent in fixed-network IM systems to an ad-hoc environment. In addition we discuss a test-bed implementation that supports collaboration between users equipped with handheld devices.

PUBLISHED, Overlay networks create a structured virtual topology above the basic transport protocol level that facilitates deterministic search and guarantees convergence. Overlay networks are evolving into a critical component for self-organizing systems. Here we outline the differences between flooding-style and overlay networks, and offer specific examples of how researchers are applying the latter to problems requiring high-speed, self-organizing network topologies.

PUBLISHED, This paper focuses on the area of dynamic spectrum management and explores how reconfigurable radio can play a major role in its realization. In particular the paper presents a case study based on IRIS (Implementing Radio in Software), which introduces software radio configurations that can be used for new spectrum allocation and spectrum management regimes. IRIS is a general-purpose processor based system for creating reconfigurable radios.

PUBLISHED, The use of a threshold certificate authority to provide cryptographic key management in mobile ad hoc networks has been suggested in the literature. We have designed and implemented such a key management service for our ad hoc networking test bed. In this paper we describe our use of distributed shared RSA key generation techniques to create a threshold certificate authority 'from scratch'. Our goal is to create a scaleable key management solution, which does not rely on prior infrastructure for its inception, and as such is formed in a truly ad hoc manner, compatible with the formation of the network itself.

PUBLISHED, This paper describes software radio and a software radio technique for automatic digital modulation scheme recognition. The modulation recognition technique is designed for a real-time software radio using general-purpose processors and is based on a modified pattern recognition and phase classifier approach. The techniques presented in this paper are designed to be robust and efficient with a processing time overhead that still allows the software radio to maintain its real-time operating objectives. Experimental results for GMSK recognition over a fading, ISI channel with AWGN and random phase noise are presented. One test scenario, where an intercepted signal is either BPSK or QPSK modulated, using an AWGN channel with random phase noise shows that correct modulation scheme classification is possible to a lower-bound channel SNR of approximately 9dB.

PUBLISHED, This paper describes an automatic modulation scheme recognition technique. The technique is designed for a real-time software radio using general purpose processors and is based on modified pattern recognition and signal space approaches. It is robust and efficient with a processing time overhead that still allows the software radio to maintain its real-time operating objectives. Both digital and analogue modulation schemes can be identified. Tests and simulations using an AWGN channel show that the SNR threshold for correct analogue modulation scheme classification is approximately 6.5 dB.

PUBLISHED, Software radio is an emerging technology that offers great opportunities for the development of future wireless systems. Many different views exist on how to build both the software and hardware required by a software radio system. This paper focuses on the use of general-purpose processors for developing software radio hardware. A software radio testbed is used to demonstrate the advantages but also limitations of using a general-purpose processor. To overcome these limitations, a particular hardware approach is presented.

PUBLISHED

PUBLISHED, The method of billing users for mobile telephony is based on systems developed over time for fixed networks. We survey the technology involved, and argue that these systems will become increasingly inadequate for large populations of mobile users where frequent roaming is involved. We present two micropayment schemes which permit a caller to inject a payment stream into the network which allows multiple network operators and value-added service providers to be paid in real time. The methods support dynamic pricing by the association of a pricing contract with the call which specifies the cost for each leg of the call route. The system will alleviate problems of mobile fraud, eliminate the need for interoperator billing agreements, and simplify payment for value-added network services. We discuss the relative merits of the two systems described and the characteristics of the prototype implementation.

PUBLISHED, The Universal Mobile Telecommunications System (UMTS) represents the emerging European standard for next generation cellular systems that transmit data as well as voice on a global basis. The UMTS goals involve the integration of evolved versions of today's second generation digital cellular systems, together with new terrestrial and satellite components. They also address a fusion of the mobile and fixed networks with a much greater role for intelligent network services. The integration scenarios take little account of the proliferation of IP based networks, and some system redesign is necessary to correct for this. To build on the strengths of GSM, the core UMTS network will evolve from the existing GSM service. UMTS support for data will probably be based on GPRS developed for GSM. Speeds available will vary from approximately 100 Kbps for a pre UMTS, GSM based system up to 2 Mbps for new UMTS radio access networks. Future mobile broadband systems may extend this up to 155 Mbps in restricted environments. The ETSI timetable for introducing these new systems shows the first equipment going into service in 2002, with full availability of third generation UMTS services by 2005

PUBLISHED, Trials of video on demand and pay-per-view systems are underway in many countries, and as a result, many cable and telecommunications companies are having to upgrade or replace their distribution networks. Video streams must be secure in order to prevent unauthorized viewing of the programs being transmitted, yet most existing security systems do not make use of the potential for bidirectional signalling in new and upgraded networks. It would prove more useful to many companies if they could use one system to test a number of different distribution networks to see if they save an acceptable quality of service. In this manner, a company could decide if existing networks could be used without substantial changes, or whether expensive upgrades or indeed replacements were justified

PUBLISHED, Considers the security aspects of communication between two management processes operating in different management domains; identifies two major risks: the security of information exchanged during the management association, and control of access to the management information base (MIB); and enumerates the various threats that must be guarded against and possible methods of attack. Security techniques, including symmetric and public key cryptosystems, are employed in the design of a method of achieving a secure management association. A scheme of authorization control for MIB access is developed. The management of an open system's network resources takes place in the context of a management association. The resources themselves are controlled by an agent process which presents a view of these resources to the outside world as a number of managed objects, each of which contains a number of attributes. The collection of objects presented to the outside world by the agent is known as the MIB. A manager process regulates the operation of the managed resources by engaging in a management association with the agent and instructing it to carry out simple operations on elements of the MIB. Within a single management domain where all processing nodes and network links are under the control of the same administration, security is not such a critical issue. However, when the management association takes place across the boundary between two separate management domains, and make use of public data networks, security issues must be considered in greater detail.

PUBLISHED, In designing and specifying a system that will be used to provide telecommunications services to a user population, it is important to identify all major actors involved, and their individual concerns at an early stage and to carry this knowledge through to the design and implementation of the service. Within the RACE EuroBridge pmject efforts are underway to provide a a toolkit and a unified system architecture to support designers and providers of advanced multi-media network services. In this paper, we examine the approaches taken to service specification by the Intelligent Network (IN) community and the RACE Open Services Architecture (ROSA) project . We investigate the applicability of these techniques to the specification and design of multi-media services to be hosted on the EuroBridge Service platform and apply the ROSA approach to a simple video-conference specification. We further outline how it can result iii a complete design that can be implemented on the EuroBridge Service Platform.