351 research outputs found
Characterization, design and re-optimization on multi-layer optical networks
L'augment de volum de trĂ fic IP provocat per l'increment de serveis multimèdia com HDTV o vĂdeo conferència planteja nous reptes als operadors de xarxa per tal de proveir transmissiĂł de dades eficient. Tot i que les xarxes mallades amb multiplexaciĂł per divisiĂł de longitud d'ona (DWDM) suporten connexions òptiques de gran velocitat, aquestes xarxes manquen de flexibilitat per suportar trĂ fic dâinferior granularitat, fet que provoca un pobre Ăşs d'ample de banda. Per fer front al transport d'aquest trĂ fic heterogeni, les xarxes multicapa representen la millor soluciĂł.
Les xarxes òptiques multicapa permeten optimitzar la capacitat mitjançant l'empaquetament de connexions de baixa velocitat dins de connexions òptiques de gran velocitat. Durant aquesta operaciĂł, es crea i modifica constantment una topologia virtual dinĂ mica grĂ cies al pla de control responsable dâaquestes operacions. Donada aquesta dinamicitat, un Ăşs sub-òptim de recursos pot existir a la xarxa en un moment donat. En aquest context, una re-optimizaciĂł periòdica dels recursos utilitzats pot ser aplicada, millorant aixĂ l'Ăşs de recursos.
Aquesta tesi estĂ dedicada a la caracteritzaciĂł, planificaciĂł, i re-optimitzaciĂł de xarxes òptiques multicapa de nova generaciĂł des dâun punt de vista unificat incloent optimitzaciĂł als nivells de capa fĂsica, capa òptica, capa virtual i pla de control. Concretament s'han desenvolupat models estadĂstics i de programaciĂł matemĂ tica i meta-heurĂstiques. Aquest objectiu principal s'ha assolit mitjançant cinc objectius concrets cobrint diversos temes oberts de recerca.
En primer lloc, proposem una metodologia estadĂstica per millorar el cĂ lcul del factor Q en problemes d'assignaciĂł de ruta i longitud d'ona considerant interaccions fĂsiques (IA-RWA). Amb aquest objectiu, proposem dos models estadĂstics per computar l'efecte XPM (el coll d'ampolla en termes de computaciĂł i complexitat) per problemes IA-RWA, demostrant la precisiĂł dâambdĂłs models en el cĂ lcul del factor Q en escenaris reals de trĂ fic.
En segon lloc i fixant-nos a la capa òptica, presentem un nou particionament del conjunt de longituds d'ona que permet maximitzar, respecte el cas habitual, la quantitat de trĂ fic extra proveĂŻt en entorns de protecciĂł compartida. Concretament, definim diversos models estadĂstics per estimar la quantitat de trĂ fic donat un grau de servei objectiu, i diferents models de planificaciĂł de xarxa amb l'objectiu de maximitzar els ingressos previstos i el valor actual net de la xarxa. DesprĂŠs de resoldre aquests problemes per xarxes reals, concloem que la nostra proposta maximitza ambdĂłs objectius.
En tercer lloc, afrontem el disseny de xarxes multicapa robustes davant de fallida simple a la capa IP/MPLS i als enllaços de fibra. Per resoldre aquest problema eficientment, proposem un enfocament basat en sobre-dimensionar l'equipament de la capa IP/MPLS i recuperar la connectivitat i el comparem amb la soluciĂł convencional basada en duplicar la capa IP/MPLS. DesprĂŠs de comparar solucions mitjançant models ILP i heurĂstiques, concloem que la nostra soluciĂł permet obtenir un estalvi significatiu en termes de costos de desplegament.
Com a quart objectiu, introduĂŻm un mecanisme adaptatiu per reduir l'Ăşs de ports opto-electrònics (O/E) en xarxes multicapa sota escenaris de trĂ fic dinĂ mic. Una formulaciĂł ILP i diverses heurĂstiques sĂłn desenvolupades per resoldre aquest problema, que permet reduir significativament lâĂşs de ports O/E en temps molt curts.
Finalment, adrecem el problema de disseny resilient del pla de control GMPLS. DesprĂŠs de proposar un nou model analĂtic per quantificar la resiliència en topologies mallades de pla de control, usem aquest model per proposar un problema de disseny de pla de control. Proposem un procediment iteratiu lineal i una heurĂstica i els usem per resoldre instĂ ncies reals, arribant a la conclusiĂł que es pot reduir significativament la quantitat d'enllaços del pla de control sense afectar la qualitat de servei a la xarxa.The explosion of IP traffic due to the increase of IP-based multimedia services such as HDTV or video conferencing poses new challenges to network operators to provide a cost-effective data transmission. Although Dense Wavelength Division Multiplexing (DWDM) meshed transport networks support high-speed optical connections, these networks lack the flexibility to support sub-wavelength traffic leading to poor bandwidth usage. To cope with the transport of that huge and heterogeneous amount of traffic, multilayer networks represent the most accepted architectural solution.
Multilayer optical networks allow optimizing network capacity by means of packing several low-speed traffic streams into higher-speed optical connections (lightpaths). During this operation, a dynamic virtual topology is created and modified the whole time thanks to a control plane responsible for the establishment, maintenance, and release of connections. Because of this dynamicity, a suboptimal allocation of resources may exist at any time. In this context, a periodically resource reallocation could be deployed in the network, thus improving network resource utilization.
This thesis is devoted to the characterization, planning, and re-optimization of next-generation multilayer networks from an integral perspective including physical layer, optical layer, virtual layer, and control plane optimization. To this aim, statistical models, mathematical programming models and meta-heuristics are developed. More specifically, this main objective has been attained by developing five goals covering different open issues.
First, we provide a statistical methodology to improve the computation of the Q-factor for impairment-aware routing and wavelength assignment problems (IA-RWA). To this aim we propose two statistical models to compute the Cross-Phase Modulation variance (which represents the bottleneck in terms of computation time and complexity) in off-line and on-line IA-RWA problems, proving the accuracy of both models when computing Q-factor values in real traffic scenarios.
Second and moving to the optical layer, we present a new wavelength partitioning scheme that allows maximizing the amount of extra traffic provided in shared path protected environments compared with current solutions. Specifically, we define several statistical models to estimate the traffic intensity given a target grade of service, and different network planning problems for maximizing the expected revenues and net present value. After solving these problems for real networks, we conclude that our proposed scheme maximizes both revenues and NPV.
Third, we tackle the design of survivable multilayer networks against single failures at the IP/MPLS layer and WSON links. To efficiently solve this problem, we propose a new approach based on over-dimensioning IP/MPLS devices and lightpath connectivity and recovery and we compare it against the conventional solution based on duplicating backbone IP/MPLS nodes. After evaluating both approaches by means of ILP models and heuristic algorithms, we conclude that our proposed approach leads to significant CAPEX savings.
Fourth, we introduce an adaptive mechanism to reduce the usage of opto-electronic (O/E) ports of IP/MPLS-over-WSON multilayer networks in dynamic scenarios. A ILP formulation and several heuristics are developed to solve this problem, which allows significantly reducing the usage of O/E ports in very short running times.
Finally, we address the design of resilient control plane topologies in GMPLS-enabled transport networks. After proposing a novel analytical model to quantify the resilience in mesh control plane topologies, we use this model to propose a problem to design the control plane topology. An iterative model and a heuristic are proposed and used to solve real instances, concluding that a significant reduction in the number of control plane links can be performed without affecting the quality of service of the network
Dynamic bandwidth allocation in multi-class IP networks using utility functions.
PhDAbstact not availableFujitsu Telecommunications Europe Lt
SDN/NFV-enabled satellite communications networks: opportunities, scenarios and challenges
In the context of next generation 5G networks, the satellite industry is clearly committed to revisit and revamp the role of satellite communications. As major drivers in the evolution of (terrestrial) fixed and mobile networks, Software Defined Networking (SDN) and Network Function Virtualisation (NFV) technologies are also being positioned as central technology enablers towards improved and more flexible integration of satellite and terrestrial segments, providing satellite network further service innovation and business agility by advanced network resources management techniques. Through the analysis of scenarios and use cases, this paper provides a description of the benefits that SDN/NFV technologies can bring into satellite communications towards 5G. Three scenarios are presented and analysed to delineate different potential improvement areas pursued through the introduction of SDN/NFV technologies in the satellite ground segment domain. Within each scenario, a number of use cases are developed to gain further insight into specific capabilities and to identify the technical challenges stemming from them.Peer ReviewedPostprint (author's final draft
Optimizing the Dynamic Distribution of Data-stream for High Speed Communications
The performances of high-speed network communications frequently rest with the distribution of data-stream. In this paper, a dynamic data-stream balancing architecture based on link information is introduced and discussed firstly. Then the algorithms for simultaneously acquiring the passing nodes and links of a path between any two source-destination nodes rapidly, as well as a dynamic data-stream distribution planning are proposed. Some related topics such as data fragment disposal, fair service, etc. are further studied and discussed. Besides, the performance and efficiency of proposed algorithms, especially for fair service and convergence, are evaluated through a demonstration with regard to the rate of bandwidth utilization. Hoping the discussion presented here can be helpful to application developers in selecting an effective strategy for planning the distribution of data-stream.Singapore-MIT Alliance (SMA
Towards a cloud enabler : from an optical network resource provisioning system to a generalized architecture for dynamic infrastructure services provisioning
This work was developed during a period where most of the optical management and provisioning system where manual and proprietary. This work contributed to the evolution of the state of the art of optical networks with new architectures and advanced virtual infrastructure services. The evolution of optical networks, and internet globally, have been very promising during the last decade. The impact of mobile technology, grid, cloud computing, HDTV, augmented reality and big data, among many others, have driven the evolution of optical networks towards current service technologies, mostly based on SDN (Software Defined Networking) architectures and NFV(Network Functions Virtualisation). Moreover, the convergence of IP/Optical networks and IT services, and the evolution of the internet and optical infrastructures, have generated novel service orchestrators and open source frameworks. In fact, technology has evolved that fast that none could foresee how important Internet is for our current lives. Said in other words, technology was forced to evolve in a way that network architectures became much more transparent, dynamic and flexible to the end users (applications, user interfaces or simple APIs).
This Thesis exposes the work done on defining new architectures for Service Oriented Networks and the contribution to the state of the art. The research work is divided into three topics. It describes the evolution from a Network Resource Provisioning System to an advanced Service Plane, and ends with a new architecture that virtualized the optical infrastructure in order to provide coordinated, on-demand and dynamic services between the application and the network infrastructure layer, becoming an enabler for the new generation of cloud network infrastructures.
The work done on defining a Network Resource Provisioning System established the first bases for future work on network infrastructure virtualization. The UCLP (User Light Path Provisioning) technology was the first attempt for Customer Empowered Networks and Articulated Private Networks. It empowered the users and brought virtualization and partitioning functionalities into the optical data plane, with new interfaces for dynamic service provisioning. The work done within the development of a new Service Plane allowed the provisioning of on-demand connectivity services from the application, and in a multi-domain and multi-technology scenario based on a virtual network infrastructure composed of resources from different infrastructure providers. This Service Plane facilitated the deployment of applications consuming large amounts of data under deterministic conditions, so allowing the networks behave as a Grid-class resource. It became the first on-demand provisioning system that at lower levels allowed the creation of one virtual domain composed from resources of different providers.
The last research topic presents an architecture that consolidated the work done in virtualisation while enhancing the capabilities to upper layers, so fully integrating the optical network infrastructure into the cloud environment, and so providing an architecture that enabled cloud services by integrating the request of optical network and IT infrastructure services together at the same level. It set up a new trend into the research community and evolved towards the technology we use today based on SDN and NFV.
Summing up, the work presented is focused on the provisioning of virtual infrastructures from the architectural point of view of optical networks and IT infrastructures, together with the design and definition of novel service layers. It means, architectures that enabled the creation of virtual infrastructures composed of optical networks and IT resources, isolated and provisioned on-demand and in advance with infrastructure re-planning functionalities, and a new set of interfaces to open up those services to applications or third parties.Aquesta tesi es va desenvolupar durant un perĂode on la majoria de sistemes de gestiĂł de xarxa òptica eren manuals i basats en sistemes propietaris. En aquest sentit, la feina presentada va contribuir a l'evoluciĂł de l'estat de l'art de les xarxes òptiques tant a nivell dâarquitectures com de provisiĂł dâinfraestructures virtuals. L'evoluciĂł de les xarxes òptiques, i d'Internet a nivell mundial, han estat molt prometedores durant l'Ăşltima dècada. L'impacte de la tecnologia mòbil, la computaciĂł al nĂşvol, la televisiĂł d'alta definiciĂł, la realitat augmentada i el big data, entre molts altres, han impulsat l'evoluciĂł cap a xarxes dâaltes prestacions amb nous serveis basats en SDN (Software Defined Networking) i NFV (Funcions de xarxa La virtualitzaciĂł). D'altra banda, la convergència de xarxes òptiques i els serveis IT, junt amb l'evoluciĂł d'Internet i de les infraestructures òptiques, han generat nous orquestradors de serveis i frameworks basats en codi obert. La tecnologia ha evolucionat a una velocitat on ningĂş podria haver predit la importĂ ncia que Internet estĂ tenint en el nostre dia a dia. Dit en altres paraules, la tecnologia es va veure obligada a evolucionar d'una manera on les arquitectures de xarxa es fessin mĂŠs transparent, dinĂ miques i flexibles vers als usuaris finals (aplicacions, interfĂcies d'usuari o APIs simples). Aquesta Tesi presenta noves arquitectures de xarxa òptica orientades a serveis. El treball de recerca es divideix en tres temes. Es presenta un sistema de virtualitzaciĂł i aprovisionament de recursos de xarxa i la seva evoluciĂł a un pla de servei avançat, per acabar presentant el disseny dâuna nova arquitectura capaç de virtualitzar la infraestructura òptica i IT i proporcionar serveis de forma coordinada, i sota demanda, entre l'aplicaciĂł i la capa d'infraestructura de xarxa òptica. Tot esdevenint un facilitador per a la nova generaciĂł d'infraestructures de xarxa en el nĂşvol. El treball realitzat en la definiciĂł del sistema de virtualitzaciĂł de recursos va establir les primeres bases sobre la virtualitzaciĂł de la infraestructura de xarxa òptica en el marc de les âCustomer Empowered Networksâ i âArticulated Private Networksâ. Amb lâobjectiu de virtualitzar el pla de dades òptic, i oferir noves interfĂcies per a la provisiĂł de serveis dinĂ mics de xarxa. En quant al pla de serveis presentat, aquest va facilitat la provisiĂł de serveis de connectivitat sota demanda per part de l'aplicaciĂł, tant en entorns multi-domini, com en entorns amb mĂşltiples tecnologies. Aquest pla de servei, anomenat Harmony, va facilitar el desplegament de noves aplicacions que consumien grans quantitats de dades en condicions deterministes. En aquest sentit, va permetre que les xarxes es comportessin com un recurs Grid, i per tant, va esdevenir el primer sistema d'aprovisionament sota demanda que permetia la creaciĂł de dominis virtuals de xarxa composts a partir de recursos de diferents proveĂŻdors. Finalment, es presenta lâevoluciĂł dâun pla de servei cap una arquitectura global que consolida el treball realitzat a nivell de convergència dâinfraestructures (òptica + IT) i millora les capacitats de les capes superiors. Aquesta arquitectura va facilitar la plena integraciĂł de la infraestructura de xarxa òptica a l'entorn del nĂşvol. En aquest sentit, aquest resultats van evolucionar cap a les tendències actuals de SDN i NFV. En resum, el treball presentat es centra en la provisiĂł d'infraestructures virtuals des del punt de vista dâarquitectures de xarxa òptiques i les infraestructures IT, juntament amb el disseny i definiciĂł de nous serveis de xarxa avançats, tal i com ho va ser el servei de re-planificaciĂł dinĂ micaPostprint (published version
Mobile-IP ad-hoc network MPLS-based with QoS support.
The support for Quality of Service (QoS) is the main focus of this thesis. Major issues and challenges for Mobile-IP Ad-Hoc Networks (MANETs) to support QoS in a multi-layer manner are considered discussed and investigated through simulation setups. Different parameters contributing to the subjective measures of QoS have been considered and consequently, appropriate testbeds were formed to measure these parameters and compare them to other schemes to check for superiority. These parameters are: Maximum Round-Trip Delay (MRTD), Minimum Bandwidth Guaranteed (MBG), Bit Error Rate (BER), Packet Loss Ratio (PER), End-To-End Delay (ETED), and Packet Drop Ratio (PDR) to name a few. For network simulations, NS-II (Network Simulator Version II) and OPNET simulation software systems were used.Dept. of Electrical and Computer Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2005 .A355. Source: Masters Abstracts International, Volume: 44-03, page: 1444. Thesis (M.Sc.)--University of Windsor (Canada), 2005
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