295 research outputs found

    ISDN at NASA Lewis Research Center

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    An expository investigation of the potential impact of the Integrated Services Digital Network (ISDN) at NASA Lewis Research Center is described. To properly frame the subject, the paper contains a detailed survey of the components of Narrowband ISDN. The principles and objectives are presented as decreed by the Consultative Committee for International Telephone and Telegraph (CCITT). The various channel types are delineated and their associated service combinations are described. The subscriber-access network functions are explained pictorially via the ISDN reference configuration. A section on switching techniques is presented to enable the reader to understand the emergence of the concept of fast packet switching. This new technology is designed to operate over the high bandwidth, low error rate transmission media that characterizes the LeRC environment. A brief introduction to the next generation of networks is covered with sections on Broadband ISDM (B-ISDN), Asynchronous Transfer Mode (ATM), and Synchronous Optical Networks (SONET). Applications at LeRC are presented, first in terms of targets of opportunity, then in light of compatibility constraints. In-place pilot projects and testing are described that demonstrate actual usage at LeRC

    Applications of satellite technology to broadband ISDN networks

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    Two satellite architectures for delivering broadband integrated services digital network (B-ISDN) service are evaluated. The first is assumed integral to an existing terrestrial network, and provides complementary services such as interconnects to remote nodes as well as high-rate multicast and broadcast service. The interconnects are at a 155 Mbs rate and are shown as being met with a nonregenerative multibeam satellite having 10-1.5 degree spots. The second satellite architecture focuses on providing private B-ISDN networks as well as acting as a gateway to the public network. This is conceived as being provided by a regenerative multibeam satellite with on-board ATM (asynchronous transfer mode) processing payload. With up to 800 Mbs offered, higher satellite EIRP is required. This is accomplished with 12-0.4 degree hopping beams, covering a total of 110 dwell positions. It is estimated the space segment capital cost for architecture one would be about 190Mwhereasthesecondarchitecturewouldbeabout190M whereas the second architecture would be about 250M. The net user cost is given for a variety of scenarios, but the cost for 155 Mbs services is shown to be about $15-22/minute for 25 percent system utilization

    Planning broadband infrastructure - a reference model

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    Solution strategies of service fulfilment Operation Support Systems for Next Generation Networks

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    Suomalainen operatiivisten tukijärjestelmien toimittaja tarjoaa ratkaisuja palvelujen aktivointiin, verkkoresurssien hallintaan ja laskutustietojen keruuseen. Nämä ratkaisut ovat pääosin käytössä langattomissa verkoissa. Tässä tutkimuksessa arvioidaan kyseisten ratkaisujen soveltuvuutta palvelutoimitusprosessien automatisointiin tulevaisuuden verkkoympäristöissä. Tarkastelun kohteena ovat runko- ja pääsyverkkojen kiinteät teknologiat, joiden suosio saavuttaa huippunsa seuraavan 5-10 vuoden aikana. Näissä verkoissa palvelujen, kuten yritys-VPN:n tai kuluttajan laajakaistan, aktivointi vaatii monimutkaisen toimitusprosessin, jonka tueksi tarvitaan ensiluokkaista tukijärjestelmää. Teknologiakatsauksen jälkeen tutkimuksessa verrataan viitteellistä tuoteportfoliota saatavilla oleviin operatiivisten tukijärjestelmien arkkitehtuurisiin viitekehyksiin, ja analysoidaan sen soveltuvuus tulevaisuuden verkkoympäristöjen palvelutoimitusprosessin automatisointiin. Myös palvelutoimitusprosessien automatisointiin soveltuvien tukijärjestelmien markkinatilanne arvioidaan, ja tämän perusteella tutkitaan optimaalisinta sovellusstrategiaa. Lopulta voidaan päätellä, että tuoteportfoliolle parhaiten soveltuvin sovellusalue on kuluttajan laajakaistan, ja siihen liittyvien kehittyneempien IP-palveluiden palvelutoimitusprosessien automatisointi.A Finnish Operation Support Systems (OSS) vendor provides solutions for service activation, network inventory and event mediation. These solutions have mostly been deployed in mobile environments. In this thesis it will be studied how feasible it is to use similar solutions for service fulfilment in Next Generation Networks (NGN). NGN is a broad term that describes some key architectural evolutions in telecommunication core and access networks that will be deployed over the next 5 to 10 years. In these networks service, e.g. Triple Play or Virtual Private Network (VPN), activations require an extensive service fulfilment process that must be supported by first-class OSS. After introducing the NGN technologies, the research compares a reference product portfolio to available service fulfilment frameworks and evaluates the applicability. The study analyses the current state of service fulfilment OSS markets and evaluates various solution strategies. Eventually it will be concluded that the most interesting and adequate solution scenario is residential broadband, including value-added IP services

    Mobile network design : Orange UK 2G to 3G mobile backhaul evolution

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    The research presented in this thesis is focused on the evolution of a GSM/GPRS (2G) cellular mobile network to UMTS (3G) and then subsequently, HSDPA. The particular technical area of research relates to the mobile backhaul network which provides the connectivity between radio cell sites which support the wide area radio coverage, and the mobile network operator’s core network. Due to the evolution of UMTS with HSDPA, the research covers the initial UMTS network rollout and then addresses the evolution of this infrastructure to support mobile broadband communications, through the introduction of HSDPA as a network upgrade. The two research questions being addressed are therefore: •How is it possible to evolve a GSM/GPRS mobile backhaul network to support a converged GSM/GPRS and UMTS cellular mobile service? •How is it possible to ensure scalability of the converged backhaul network given the introduction of HSDPA and associated mobile broadband data growth? The starting point of the research is an established GSM and GPRS commercial network in the UK and the study is based on the design of the Orange network and focused on the period 2000 to 2010. During this period the author was working as Principal Network Designer within Orange and had overall responsibility for the strategy, architecture and design of the UK mobile backhaul network. The thesis provides a detailed explanation of the novel network design that was adopted and how it was evolved throughout the ten year period covered by the research. The research proves that the original static TDM approach was not suitable for UMTS and therefore the outcome was the introduction of an ATM network with optimisation based on traffic class rt-VBR over protected STM-1 transmission links. HSDPA drove further traffic growth and resulted in an evolution of the solution to ensure massive scalability was supported through the migration to Carrier Ethernet and implementation of pseudo-wires. In addition, to providing a technical description of the network design, the thesis also aims to provide a historical record of the technologies and equipment used during this period of rapid change within the UKs mobile networks

    Multiplexer Technology in Utility Automation

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    In utility automation systems, data communication links have the essential role to convey real-time system between control centers and substations. Therefore, reliable and flexible communications are vital to run modern utility network in a safe and properly controlled way. In this thesis, possibilities of multiplexer technology in communications for utility automation systems are reviewed. At the beginning of this thesis, theory about multiplexing, especially SDH data transmission technology, and essential utility automation systems are discussed. Thereafter, the thesis concentrates on the characteristics and potential applications of the employer’s multiplexer device. Eventually, the performance requirements for the device are analyzed from the utility automation systems’ perspective and also some performance figures are measured with a build-up test system. Multiplexer technology was found to be well suitable for the underlying communications in utility automation systems. Especially the efficient protection schemes and network manageability makes SDH systems highly available and ensures quick reconfiguration in fault situations. Teleprotection that makes very fast operating times for power line protection possible, came up as the most important application.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

    Technology Directions for the 21st Century

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    New technologies will unleash the huge capacity of fiber-optic cable to meet growing demands for bandwidth. Companies will continue to replace private networks with public network bandwidth-on-demand. Although asynchronous transfer mode (ATM) is the transmission technology favored by many, its penetration will be slower than anticipated. Hybrid networks - e.g., a mix of ATM, frame relay, and fast Ethernet - may predominate, both as interim and long-term solutions, based on factors such as availability, interoperability, and cost. Telecommunications equipment and services prices will decrease further due to increased supply and more competition. Explosive Internet growth will continue, requiring additional backbone transmission capacity and enhanced protocols, but it is not clear who will fund the upgrade. Within ten years, space-based constellations of satellites in Low Earth orbit (LEO) will serve mobile users employing small, low-power terminals. 'Little LEO's' will provide packet transmission services and geo-position determination. 'Big LEO's' will function as global cellular telephone networks, with some planning to offer video and interactive multimedia services. Geosynchronous satellites also are proposed for mobile voice grade links and high-bandwidth services. NASA may benefit from resulting cost reductions in components, space hardware, launch services, and telecommunications services
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