Network Infrastructure (network + infrastructure)

Distribution by Scientific Domains

Selected Abstracts

Mobile-initiated network-executed SIP-based handover in IMS over heterogeneous accesses

Wei-Kuo Chiang
Abstract The services of next generation networks are envisioned to be potentially capable of seamless mobility in spite of the heterogeneity in underlying access technologies. It is undoubted that to accomplish seamless services across heterogeneous networking environments gets harder in case of simultaneous mobility. In this article, we propose a mobile-initiated network-executed (MINE) session initial protocol (SIP)-based handover mechanism to facilitate simultaneous mobility in IP multimedia subsystem over heterogeneous accesses. The novelty of the proposed approach is that no changes are required to the existing network infrastructure since handover decision is fully made by the mobile host (MH) and handover execution is performed by a new-added application server called mobility server (MS). When the MH decides to initiate a handover and obtains a new IP address, it will send a SIP Publish message to trigger the MS to carry out the handover execution. With the network-executed design of the MINE, the MS can perform third-party registration for security re-association and third-party call control for session re-establishment in parallel. Moreover, the Master,Slave Determination procedures derived from H.245 are used in the MS to handle fairly the racing conditions resulting from simultaneous mobility such that redundant message flows are eliminated. Mathematical analyses present that the MINE can shorten the handover latency and reduce power consumption, as observed from a comparison with the integrated solution of an optimized macro-mobility mechanism and a receiver-side simultaneous mobility approach. Copyright © 2010 John Wiley & Sons, Ltd. [source]

Performance issues of bandwidth management in ATM networks

Christos Bouras
Abstract In our days, efficient management of the available network resources becomes a critical issue, both from a functional point of view (so that users can be provided with the bandwidth they need), and an economical point of view (so that carriers can satisfactorily and efficiently serve as many customers as possible and at the same time increase their revenue). In this paper we consider a bandwidth control scheme (i.e. managed bandwidth service) for an ATM network infrastructure which is applied to the Greek research and technology network (GRNET). We present some methods that we have tested (in a simulation setting) in order to increase the efficiency of the system and the utilization of the available bandwidth. More specifically, we consider a bandwidth-resizing algorithm for virtual paths, in order to keep the allocated bandwidth very close to the bandwidth actually used. This leads to an increased number of accepted requests and better network utilization. We, also, use the simulation results in order to get an estimation of the effective bandwidth for VBR paths that can be used in call admission. Finally, we consider a semi-offline scheme where requests are gathered and considered for acceptance in regular intervals. Simulation results show an increase in the utilization of resources. As a further improvement, we allow connections to be allocated a little before or after the time initially requested. This leads to further improvement in network utilization. All the improvement schemes were tested with the ATM-TN simulator and the results look promising. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Quality of service for satellite IP networks: a survey

Sastri Kota
Abstract The future media rich applications such as media streaming, content delivery distribution and broadband access require a network infrastructure that offers greater bandwidth and service level guarantees. As the demand for new applications increases, ,best effort' service is inadequate and results in lack of user satisfaction. End-to-end quality of service (QoS) requires the functional co-operation of all network layers. To meet future application requirements, satellite is an excellent candidate due to features such as global coverage, bandwidth flexibility, broadcast, multicast and reliability. At each layer, the user performance requirements should be achieved by implementation of efficient bandwidth allocation algorithms and satellite link impairment mitigation techniques. In this paper, a QoS framework for satellite IP networks including requirements, objectives and mechanisms are described. To fully understand end-to-end QoS at each layer, QoS parameters and the current research are surveyed. For example at physical layer (modulation, adaptive coding), link layer (bandwidth allocation), network layer (IntServ/DiffServ, MPLS traffic engineering), transport layer (TCP enhancements, and alternative transport protocols) and security issues are discussed. Some planned system examples, QoS simulations and experimental results are provided. The paper also includes the current status of the standardization of satellite IP by ETSI, ITU and IETF organizations. Copyright © 2003 John Wiley & Sons, Ltd. [source]

Web communication services and the PacketIN® application hosting environment

Yang Chen
Large telecommunication customers are migrating their network infrastructure to support new converged services, while containing their operating costs. Deploying converged services on the networks today represents great opportunities to network service providers for new revenue generation. It brings big challenges as well, due to the requirements for a service platform with high capability to deal with the complexity of the network infrastructure, the difficulty of interoperability between different service platforms, and the diversity of signaling protocols and application programming interfaces (APIs). The Lucent PacketIN® application hosting environment (AHE) provides a solution that empowers network service providers to deliver a wide variety of enhanced services over the converged (packet and circuit, wireline and wireless) networks. It enables the creation and deployment of enhanced services on converged networks via the open service platform with interoperability, programmability, scalability, and wide protocol compliance. In particular, a new class of services is presented to demonstrate the transformation of telecommunication services that is enabled through Web presence. This article gives an overview of the PacketIN AHE with the focus on the customer values, the architecture, and enabling capability to deploy advanced applications and services. A new service portal, enterprise communication, is presented as an example of the innovation and implementation enabled by the service enabling environment. The enterprise communication provides Web access to presence information, instant messaging, third-party call management, and location. This convergence of features is enabled by the PacketIN AHE integration of the public switched telephone network (PSTN), session initiation protocol (SIP), and H.323 protocols through standard open APIs. The voice communication protocols are combined with a Web access interface to establish a new Internet presence, while leveraging existing switching products and reusing deployed communication networks and services. © 2002 Lucent Technologies Inc. [source]

A Methodological Overview of Network Vulnerability Analysis

ABSTRACT Evaluating network infrastructures for potential vulnerabilities is an important component of strategic planning, particularly in the context of managing and mitigating service disruptions. Many methods have been proposed to facilitate such analysis, providing different interpretations of infrastructure vulnerability. The primary approaches that have been employed for network vulnerability analysis can be broadly classified as scenario-specific, strategy-specific, simulation, and mathematical modeling methodologies. Research on network vulnerability assessment has traditionally focused on one of these methodologies without consideration of the others. This article highlights the important implications of methodology for both infrastructure planning and policy development. To better understand the theoretical and practical trade-offs associated with methodology selection, this article provides a review of these categories of analysis, examining benefits and shortcomings with regard to practical planning issues and policy interpretation. [source]

Investigating the performance of a middleware protocol architecture for tele-measurement

Luca Berruti
Abstract The rapid growth of network infrastructures and the large availability of instrumentation supporting remote control have encouraged the deployment of complex and sophisticated laboratories and the design of software platforms for accessing the resources present there. Although the market offers several solutions to remotely manage equipment, little attention has been paid to the hardware and software architectures devoted to control distance learning experimental environments and to manage laboratories consisting of heterogeneous devices. The paper illustrates the architectural approach adopted within the LABNET project and describes in detail the main software components of the devised platform, which allows to exploit the instrumentation via a common Web user interface, thus making the system available independent of any specific (commercial) environment or application. Specifically, attention is focused on the LABNET server (LNS), which represents the supervising central unit and, therefore, a very critical element of the system. The paper mainly points out the architecture and protocols at the basis of the LNS and discusses a set of performance tests aimed at proving the effectiveness of the system and comparing it with a well-known commercial solution. Copyright © 2007 John Wiley & Sons, Ltd. [source]

A study of a routing attack in OLSR-based mobile ad hoc networks

Bounpadith Kannhavong
Abstract A mobile ad hoc network (MANET) is a collection of mobile nodes which are able to communicate with each other without relying on predefined infrastructures or central administration. Due to their flexibilities and easy deployment, MANET can be applied in situation where network infrastructures are not available. However, due to their unique characteristics such as open medium and the lack of central administration, they are much more vulnerable to malicious attacks than a conventional infrastructured wireless network. MANET employs routing to provide connectivity for mobile nodes that are not within direct wireless transmission range. Existing routing protocols in MANET assume a trusted and cooperative environment. However, in hostile environment, mobile nodes are susceptible to various kinds of routing attacks. In this paper, we show that an OLSR MANET node is prone to be isolated by malicious attack called Node Isolation attack. After analysing the attack in detail, we present a technique to mitigate the impact of the attack and improve the performance of the network when the attack is launched. The results of our implementations illustrate that the proposed solution can mitigate the attack efficiently. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Practical performance of digital cellular system in mass rapid transit environments

Y. P. ZhangArticle first published online: 13 DEC 200
Abstract Leaky coaxial cables have found applications in the creation of network infrastructures for mobile and personal communication services in underground and enclosed spaces. A digital cellular system based on the GSM 900 standard and using radiated mode leaky coaxial cables has been implemented in an underground mass rapid transit environment. This paper presents the practical performance evaluation of the system. First, we start with a brief introduction of a radiated mode leaky coaxial cable and the digital cellular system GSM 900, and then we move into a full description of the measurement campaign; next we focus on an analysis of the measured performance data about received signal level, received signal quality, speech quality index and grade of service. The results show that the system performance is generally good; however, the poor system performance often occurs at the terminals of the leaky coaxial cable. In addition, it is found that the system performance is highly correlated with the density of train passenger. The higher train passenger density degrades the system performance. Copyright © 2004 John Wiley & Sons, Ltd. [source]