25 research outputs found
Virtual network function development for NG-PON Access Network Architecture
Dissertação de mestrado em Engenharia de Redes e Serviços TelemáticosThe access to Internet services on a large scale, high throughput and low latency has grown
at a very high pace over time, with a growing demand for media content and applications
increasingly oriented towards data consumption. This fact about the use of data at the edge
of the network requires the Central Offices (CO) of telecommunication providers, to be pre pared to absorb these demands. COs generally offer data from various access methods, such
as Passive Optical Network (PON) technologies, mobile networks, copper wired and oth ers. For each of these technologies there may be different manufacturers that support only
their respective hardware and software solutions, although they all share different network
resources and have management, configuration and monitoring tools (Fault, Configuration,
Accounting, Performance, and Security management - FCAPS) similar, but being distinct and
isolated from each other, which produces huge investment in Capital Expenditure (CAPEX)
and Operational Expenditure (OPEX) and can cause barriers to innovation. Such panora mas forced the development of more flexible, scalable solutions that share platforms and net work architectures that can meet this need and enable the evolution of networks. It is then
proposed the architecture of Software-Defined Network (SDN) which has in its proposal to
abstract the control plane from the data plane, in addition to the virtualization of several Net work Function Virtualization (NFV). The SDN architecture allows APIs and protocols such
as Openflow, NETCONF / YANG, RESTCONF, gRPC and others to be used so that there is
communication between the various hardware and software elements that compose the net work and consume network resources, such as services AAA, DHCP, routing, orchestration,
management or various applications that may exist in this context.
This work then aims at the development of a virtualized network function, namely a VNF
in the context of network security to be integrated as a component of an architecture guided
by the SDN paradigm applied to broadband networks, and also adherent to the architecture
OB-BAA promoted by the Broadband Forum. Such OB-BAA architecture fits into the initia tive to modernize the Information Technology (IT) components of broadband networks, more
specifically the Central Offices. With such development, it was intended to explore the con cepts of network security, such as the IEEE 802.1X protocol applied in NG-PON networks
for authentication and authorization of new network equipment. To achieve this goal, the
development of the applications was based on the Golang language combined with gRPC
programmable interfaces for communication between the various elements of the architec ture. Network emulators were initially used, and then the components were ”containerized”
and inserted in the Docker and Kubernetes virtualization frameworks. Finally, performance
metrics were analyzed in the usage tests, namely computational resource usage metrics (CPU,
memory and network I/O), in addition to the execution time of several processes performed
by the developed applications.O acesso aos serviços de Internet em larga escala, alto débito e baixa latência têm crescido em
um ritmo bastante elevado ao longo dos tempos, com uma demanda crescente por conteĂşdos
de media e aplicações cada vez mais orientadas ao consumo de dados. Tal fato acerca da uti lização de dados na periferia da rede, obriga a que os Central Offices (CO) dos provedores de
telecomunicações estejam preparados para absorver estas demandas. Os CO geralmente re cebem dados de diversos métodos de acesso, como tecnologias Passive Optical Network (PON),
redes mĂłveis, cabladas em cobre, entre outros. Para cada uma destas tecnologias pode haver
diferentes fabricantes que suportam somente suas respetivas soluções de hardware e software,
apesar de todas compartilharem diversos recursos de rede e possuĂrem ferramentas de gestĂŁo,
configuração e monitoração (Fault-management, Configuration, Accounting, Performance e
Segurança - FCAPS) similares, mas serem distintas e isoladas entre si, o que se traduz em
um enorme investimento em Capital Expenditure (CAPEX) e Operational Expenditure (OPEX) e
pode causar barreiras à inovação. Tais panoramas forçaram o desenvolvimento de soluções
mais flexĂveis, escaláveis e que compartilhem plataformas e arquiteturas de redes que pos sam suprir tal necessidade e possibilitar a evolução das redes. Propõe-se entĂŁo a arquitetura
de redes definidas por software (Software-Defined Network - SDN) que tem em sua proposta
abstrair o plano de controle do plano de dados, além da virtualização de diversas funções de
rede (Network Function Virtualization - NFV). A arquitetura SDN possibilita que API’s e pro tocolos como Openflow, NETCONF/YANG, RESTCONF, gRPC e outros, sejam utilizados
para que haja comunicação entre os diversos elementos de hardware e software que estejam a
compor a rede e a consumir recursos de redes, como serviços de AAA, DHCP, roteamento,
orquestração, gestão ou diversas outras aplicações que possam existir neste contexto.
Este trabalho visa então o desenvolvimento de uma função de rede virtualizada nomeada mente uma (Virtual Network Function - VNF) no âmbito de segurança de redes a ser integrada
como um componente de uma arquitetura orientada pelo paradigma de SDN aplicado a re des de banda larga, e aderente também à arquitetura OB-BAA promovida pelo Broadband Fo rum. Tal arquitetura OB-BAA se enquadra na iniciativa de modernização dos componentes
de Tecnologia da Informação (TI) das redes de banda larga, mais especificamente dos Cen tral Offices. Com tal desenvolvimento pretende-se explorar conceitos de segurança de redes,
como o protocolo IEEE 802.1X aplicado em redes NG-PON para autenticação e autorização
de novos equipamentos de rede. Para atingir tal objetivo, utilizou-se desenvolvimento de
aplicações baseadas na linguagem Golang aliado com interfaces programáveis gRPC para
comunicação entre os diversos elementos da arquitetura. Para emular tais componentes,
utilizou-se inicialmente emuladores de rede, e em um segundo momento os componentes
foram ”containerizados” e inseridos nos frameworks de virtualização Docker e Kubernetes.Por fim, foram analisadas métricas de desempenho nos testes executados, nomeadamente
métricas de utilização de recursos computacionais (CPU, memória e tráfego de rede), além
do tempo de execução de diversos processos desempenhados pelas aplicações desenvolvidas
Optisen liityntäverkon ohjelmoitavien logiikkapiirien ohjelmoinnin suunnittelu
Tiedonsiirtoverkkojen rakenne elää muutoksen aikaa.
Perinteisesti data-, puhelin- ja laajakaistaliikenne on siirretty erillisissä verkoissa, joiden samanaikainen ylläpitäminen tuottaa ylimääräisiä kustannuksia operaattoreille.
Lisäksi uudet interaktiiviset palvelut vaativat toimiakseen sellaista palvelunlaatua, jota nykyiset tiedonsiirtoverkot eivät kykene tarjoamaan.
Näiden epäkohtien johdosta tiedonsiirtoverkkojen kehityksessä tähdätään uusiin, entistä joustavampiin ja eri toiminnot yhdistäviin verkkoratkaisuihin, joissa tiedonsiirron palvelunlaadulla on entistä suurempi merkitys.
Tällä hetkellä tiedonsiirtoverkkojen kokonaistiedonsiirtonopeuden kasvun pullonkaulatekijäksi on muodostunut kaupunkialueiden syöttöverkkojen monimutkaisuus, millä on suuri vaikutus myös tiedonsiirron palvelunlaatuun.
TEKES-rahoitteisessa OAN-projektissa kehitetään uutta ja yksinkertaisempaa kaupunkialueen optista syöttöverkkoratkaisua, jolla alueen palvelunlaatua saataisiin parannettua.
Tämä diplomityö on tehty osana OAN-projektia.
Työssä kuvataan tiedonsiirtoverkkojen tämänhetkinen rakenne, tarkastellaan sen ongelmia ja tulevaisuuden kehityssuuntia, sekä esitetään pohdintojen pohjalta rakennettu malli tulevaisuuden tiedonsiirtoverkkojen rakenteelle.
Työssä esitetään myös HDL-implementointiprosessiin kuuluvat työvaiheet sekä käydään läpi suunnitelma OAN-projektissa toteutettavan prototyypin ohjelmoitavien logiikkapiirien ohjelmaa varten
Economically sustainable public security and emergency network exploiting a broadband communications satellite
The research contributes to work in Rapid Deployment of a National Public Security and Emergency Communications Network using Communication Satellite Broadband. Although studies in Public Security Communication networks have examined the use of communications satellite as an integral part of the Communication Infrastructure, there has not been an in-depth design analysis of an optimized regional broadband-based communication satellite in relation to the envisaged service coverage area, with little or no terrestrial last-mile telecommunications infrastructure for delivery of satellite solutions, applications and services.
As such, the research provides a case study of a Nigerian Public Safety Security Communications Pilot project deployed in regions of the African continent with inadequate terrestrial last mile infrastructure and thus requiring a robust regional Communications Satellite complemented with variants of terrestrial wireless technologies to bridge the digital hiatus as a short and medium term measure apart from other strategic needs.
The research not only addresses the pivotal role of a secured integrated communications Public safety network for security agencies and emergency service organizations with its potential to foster efficient information symmetry amongst their operations including during emergency and crisis management in a timely manner but demonstrates a working model of how analogue spectrum meant for Push-to-Talk (PTT) services can be re-farmed and digitalized as a “dedicated” broadband-based public communications system. The network’s sustainability can be secured by using excess capacity for the strategic commercial telecommunication needs of the state and its citizens. Utilization of scarce spectrum has been deployed for Nigeria’s Cashless policy pilot project for financial and digital inclusion. This effectively drives the universal access goals, without exclusivity, in a continent, which still remains the least wired in the world
NASA Tech Briefs, August 1994
Topics covered include: Computer Hardware; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences; Books and Reports
DSP-enabled Reconfigurable Optical Network Devices and Architectures for Cloud Access Networks
To meet the ever-increasing bandwidth requirements, the rapid growth in highly dynamic traffic patterns, and the increasing complexity in network operation, whilst providing high power consumption efficiency and cost-effectiveness, the approach of combining traditional optical access networks, metropolitan area networks and 4-th generation (4G)/5-th generation (5G) mobile front-haul/back-haul networks into unified cloud access networks (CANs) is one of the most preferred “future-proof” technical strategies. The aim of this dissertation research is to extensively explore, both numerically and experimentally, the technical feasibility of utilising digital signal processing (DSP) to achieve key fundamental elements of CANs from device level to network architecture level including: i) software reconfigurable optical transceivers, ii) DSP-enabled reconfigurable optical add/drop multiplexers (ROADMs), iii) network operation characteristics-transparent digital filter multiple access (DFMA) techniques, and iv) DFMA-based passive optical network (PON) with DSP-enabled software reconfigurability.
As reconfigurable optical transceivers constitute fundamental building blocks of the CAN’s physical layer, digital orthogonal filtering-based novel software reconfigurable transceivers are proposed and experimentally and numerically explored, for the first time. By making use of Hilbert-pair-based 32-tap digital orthogonal filters implemented in field programmable gate arrays (FPGAs), a 2GS/s@8-bit digital-to-analogue converter (DAC)/analogue-to-digital converter (ADC), and an electro-absorption modulated laser (EML) intensity modulator (IM), world-first reconfigurable real-time transceivers are successfully experimentally demonstrated in a 25km IMDD SSMF system. The transceiver dynamically multiplexes two orthogonal frequency division multiplexed (OFDM) channels with a total capacity of 3.44Gb/s. Experimental results also indicate that the transceiver performance is fully transparent to various subcarrier modulation formats of up to 64-QAM, and that the maximum achievable transceiver performance is mainly limited by the cross-talk effect between two spectrally-overlapped orthogonal channels, which can, however, be minimised by adaptive modulation of the OFDM signals. For further transceiver optimisations, the impacts of major transceiver design parameters including digital filter tap number and subcarrier modulation format on the transmission performance are also numerically explored.
II
Reconfigurable optical add/drop multiplexers (ROADMs) are also vital networking devices for application in CANs as they play a critical role in offering fast and flexible network reconfiguration. A new optical-electrical-optical (O-E-O) conversion-free, software-switched flexible ROADM is extensively explored, which is capable of providing dynamic add/drop operations at wavelength, sub-wavelength and orthogonal sub-band levels in software defined networks incorporating the reconfigurable transceivers. Firstly, the basic add and drop operations of the proposed ROADMs are theoretically explored and the ROADM designs are optimised. To crucially validate the practical feasibility of the ROADMs, ROADMs are experimentally demonstrated, for the first time. Experimental results show that the add and drop operation performances are independent of the sub-band signal spectral location and add/drop power penalties are <2dB. In addition, the ROADMs are also robust against a differential optical power dynamic range of >2dB and a drop RF signal power range of 7.1dB.
In addition to exploring key optical networking devices for CANs, the first ever DFMA PON experimental demonstrations are also conducted, by using two real-time, reconfigurable, OOFDM-modulated optical network units (ONUs) operating on spectrally overlapped multi-Gb/s orthogonal channels, and an offline optical line terminal (OLT). For multipoint-to-point upstream signal transmission over 26km SSMF in an IMDD DFMA PON, experiments show that each ONU achieves a similar upstream BER performance, excellent robustness to inter-ONU sample timing offset (STO) and a large ONU launch power variation range. Given the importance of IMDD DFMA-PON channel frequency response roll-off, both theoretical and experimental explorations are undertaken to investigate the impact of channel frequency response roll-off on the upstream transmission of the DFMA PON system Such work provides valuable insights into channel roll-off-induced performance dependencies to facilitate cost-effective practical network/transceiver/component designs
NASA Tech Briefs, February 2002
Topics include:a technology focus on computers, electronic components and systems, software, materials, mechanics,physical sciences machinery, manufacturing/fabrication, mathematics, book and reports, motion control tech briefs and a special section on Photonics Tech Briefs
International Conference on Civil Infrastructure and Construction (CIC 2020)
This is the proceedings of the CIC 2020 Conference, which was held under
the patronage of His Excellency Sheikh Khalid bin Khalifa bin Abdulaziz Al
Thani in Doha, Qatar from 2 to 5 February 2020. The goal of the conference
was to provide a platform to discuss next-generation infrastructure and its
construction among key players such as researchers, industry professionals
and leaders, local government agencies, clients, construction contractors and
policymakers.
The conference gathered industry and academia to disseminate their research
and field experiences in multiple areas of civil engineering. It was also a unique
opportunity for companies and organizations to show the most recent
advances in the field of civil infrastructure and construction.
The conference covered a wide range of timely topics that address the needs
of the construction industry all over the world and particularly in Qatar. All
papers were peer reviewed by experts in their field and edited for publication.
The conference accepted a total number of 127 papers submitted by authors
from five different continents under the following four themes:
Theme 1: Construction Management and Process
Theme 2: Materials and Transportation Engineering
Theme 3: Geotechnical, Environmental, and Geo-environmental Engineering
Theme 4: Sustainability, Renovation, and Monitoring of Civil InfrastructureThe list of the Sponsors are listed at page 1
Satellite power systems (SPS) concept definition study. Volume 2, part 1: System engineering
Top level trade studies are presented, including comparison of solid state and klystron concepts, higher concentration on the solar cells, composite and aluminum structure, and several variations to the reference concept. Detailed trade studies are presented in each of the subsystem areas (solar array, power distribution, structures, thermal control, attitude control and stationkeeping, microwave transmission, and ground receiving station). A description of the selected point design is also presented
2009 - 2010 University Catalog
Volume 99, Number 1, October 30, 2009
Published once a year, October 30, 2009https://scholarsrepository.llu.edu/univcatalog/1011/thumbnail.jp