On Supporting Secure Information Distribution in Heterogeneous Systems Using Standard Technologies

This paper presents an integrated security architecture for heterogeneous distributed systems. Based on the MPEG-21 standard data structures and the MPEG-M standard services, the proposed architecture provides a unified, fine-grained solution for protecting each information unit circulated in the system. In this context, a novel scheme for translating the access control rules, initially expressed by means of the standard MPEG-21 Rights Expression Language, into Ciphertext-Policy Attribute-Based Encryption access trees is introduced, thereby enabling offline authorization based on the users’ attributes, also encapsulated and certified using MPEG-21 licenses. The proposed framework provides a detailed approach in all the steps of the information protection process, from attribute acquisition to data encryption and decryption.     

QMTool: an XML-based management platform for QoS-aware IP networks

Technological and human factors have contributed to the increasing complexity of the network management problem. Heterogeneity and globalization of network resources have, on one hand, increased user expectations for flexible and easy-to-use environments and, on the other, propounded entirely novel ways to face the management problem. Several research efforts recognize the need for integrated solutions to manage both network resources and services in open and global environments. Undoubtedly, these solutions should permit the coexistence of different management models and should interoperate with legacy systems. The presented management system, QoS management tool (QMTool), aspires to address the heterogeneity, complexity, and dynamic behavior of QoS-enabled IP networks by taking advantage of the optimum fit of a number of novel technologies. A layered framework architecture, including element, network management, and visualization service, is provided, and a high level of information abstraction in network configuration and monitoring is introduced mainly based on the capabilities of the Extensible Markup Language (XML). Moreover, the functional components for providing (re-)configuration, fault management monitoring, and network visualization facilities are also presented, followed by notes of implementation issues.     

Fast handover support in a WLAN environment: challenges and perspectives

While handover management has traditionally used radio-technology-specific mechanisms, the need for integration of this diverse network environment has obviated the "push" of the handover functionality to the generic IP layer that serves the rendezvous point of underlying technologies. In this context, we study and analyze the implications of the link-layer agnostic operation of IP handover control on handover performance, having as a reference the fast mobile IPv6 protocol. We show that the behavior of the protocol (i.e., whether a reactive or proactive operation will be executed) is highly dependent on the timely availability of link layer information. A non-exhaustive list of generic link-layer triggers used for this purpose, as identified by the IEEE 802.21 WG, is also presented. Last, we apply this generic framework to a WLAN environment running fast mobile IPv6 and study the improvements in fast handoff support.     

Simulative analysis of optimal resource allocation and routing inIBCN's

The problem of resource allocation for future integrated broadband communication networks (IBCNs) is addressed. It mainly involves resource allocation at the connection level. The resource allocation problem is decomposed into the following interdependent tasks: given that a network can accommodate the bandwidth demand of a call request, determine a route for the corresponding asynchronous transfer mode (ATM) virtual connection; and allocate bandwidth, i.e. links inside the trunks of the chosen route, to this connection according to predefined limits on bandwidth use by various service calls. Various link allocation schemes combined with routing algorithms are examined. Their performance in terms of service call blocking is evaluated using a software package developed, for that purpose. It is shown that the traditional complete sharing (CS) and complete partitioning (CP) policies are not adequate for IBCNs. Movable boundary (MB) policies are more flexible and present near-optimal performance when access of broadband service to narrowband service resources is allowed and suitable routing algorithms are dynamically applied     

Parlay‐based service provision in circuit‐ and packet‐switched telecommunications networks

The spectrum of potential value added services over Internet telephony is wide, but the current service provision solutions are inadequate or proprietary. The nature of Internet differs significantly from that of circuit switched network, however, VoIP architectures can capitalize service control architectures in the PSTN world. We describe such an architecture based on the intelligent network and the Parlay, employing distributed objects and mobile agents as enabling technologies. This architecture has been implemented in the PSTN and the Internet and it has provided a framework for service provisioning, augmenting the space of supported services. Copyright © 2004 John Wiley & Sons, Ltd.     

A transparent MAC method for bandwidth sharing and CDV control atthe ATM layer of passive optical networks

In the quest for a way to bring local loop costs down and make B-ISDN affordable to small traffic customers, the passive optical networks (PONs) in combination with ATM (APONs) have been investigated extensively. To achieve the required medium sharing on a time division multiplexing (TDMA) basis, an arbitration mechanism is required in the upstream direction. The resulting multiplexing and concentration, though it is the source of significant savings, it has been plagued by the penalty of high distortion of the traffic profiles at the exit of the PON. The preventive congestion control method of ATM is rather intolerant of such distortions in the multiplexing stages. Arbitration methods which are either semistatic or based on number of arrivals per reservation period, cause very high cell delay variation (CDV). The cell clustering introduced by the arbitration method cannot be distinguished from peak rate violations of the contract by the policing unit. The result is either unwarranted rejections of conforming cells or unacceptably low utilization. The scheme presented herewith maintains a CDV behavior comparable to that of a common centralized FIFO multiplexer. It relies on a meticulous recording of the arrival timing of cells enabling a subsequent allocation of slots which produces almost the same output (and CDV) as the centralized FLFO multiplexer. A compact coding of the timing information restricts bandwidth waste for control information to the size found in other similar protocols. The most important feature is that the scheme is amenable to easy hardware implementation and does not require any call related information     

Architectural and Control Aspects of the Multi-Host ATM Subscriber Loop 1

The Access Network (AN) part of the B-ISDN aimsat concentrating the traffic of a number of differentUser Network Interfaces (UNIs) and routing this trafficto the appropriate Service Node (SN) through a broadbandV interface (referred as VB). Naturally, the emphasis onAN design is to provide cost-efficient implementationswithout degrading the agreed Quality of Service (QoS).This is both the reduction of the AN physical equipmentand in the limitations imposed on the AN functionalitysuch as the inability to interpret signalinginformation. The lack of connection-related informationforces the establishment of several AN internalmechanisms that compensate for the effects of trafficconcentration. In our attempt to generalize and extendresults and experiences obtained from out in the specification, design and implementationof an Asynchronous Transfer Mode (ATM)-based AN, weintroduce the concept of a real-time VB interfaceControl Protocol (V-CP). We demonstrate the V-CP abilityto serve for a number of AN internal functions whilepreserving the highest possible degree of transparencyto the SN. The V-CP services provide for the dynamicoperation of the AN by conveying all thoseconnection-related parameters required for dynamicresource allocation, traffic policing and routing in theAN, as well as information on the status of the ANbefore a new connection is accepted by the SN. The V-CPoperates in real time on a connection by connectionbasis. This is reflected in its simple design making itconsiderably faster than usual managementprotocols.     

DVB-T Network Planning: A Case Study for Greece

Terrestrial digital video broadcasting (DVB-T) network planning is the main interest of this article, along with a case study for Greece. The basic principles and the guidelines of the DVB-T planning process are presented, in conjunction with their application to the establishment of the Greek DVB-T allotment plan. The procedures described in this article were followed by the authors during the International Telecommunication Union (ITU) DVB-T planning project that concluded with the ITU's Regional Radiocommunication Conference 2006 (RRC-06), and the Geneva (GE-06) frequency plan for terrestrial digital radio broadcasting.     

On the design of a privacy aware authorization engine for collaborative environments

Business networking has substantially reshaped common enterprise procedures and has paved the way for the development of ground-breaking information sharing patterns and inter-organizational cooperative practices. Yet, critical issues still stand unaddressed; privacy and sensitive information confidentiality implications threaten to diminish the economic and social benefits derived from online collaboration. Nevertheless, privacy preservation refers to a multidimensional and cross-disciplinary subject, accompanied by both legal as well as technical challenges. In this context, this paper describes the design of a privacy-aware decision engine operating within synergistic contexts. Decision making regarding the production of authorizations and information usage rules is founded on a detailed privacy context and the enforcement of a deductive reasoning algorithm. The proposed reasoning process spans two distinct phases, taking into account an a priori perspective of the system while at the same time maintaining responsiveness in dynamic contexts.     

Architecture for reliable service discovery and delivery in manets based on power management employing slp extensions

Limited energy resources and mobility issues affect the topology of ad hoc networks and introduce difficulties in service discovery. The high possibility of a link breakdown due to low energy supplies in a ubiquitous computing environment, such as a mobile ad hoc network (MANET), raises service-provider selection issues with regard to achieving the best possible service reliability. Every node requiring a specific service must choose a provider under certain criteria. This article provides an overview of standardized service-discovery and delivery solutions. In addition, a novel architecture is proposed which provides the ability to select a service provider by taking into account metrics such as the power supplies of the service provider and concomitant path towards the destination. The proposed algorithm is decentralized and based on service location protocol version 2 (SLPvZ) extensions