Backbone networks are responsible for long-haul data transport serving many clients with a large volume of data. Since long-haul data transport service must rely on a robust high capacity network the current technology broadly adopted by the industry is Wavelength Division Multiplexing (WDM). WDM networks enable one single ber to operate with multiple high capacity channels, drastically increasing the ber capacity. In WDM networks each channel is associated with an individual wavelength. Therefore a whole wavelength capacity is assigned to a connection, causing waste of bandwidth in case the connection bandwidth requirement is less than the channel total capacity. In the last half decade, Elastic Optical Networks (EON) have been proposed and developed based on the fexible use of the optical spectrum known as the exigrid. EONs are adaptable to clients requirements and may enhance optical networks performance. For these reasons, research community and data transport providers have been demonstrating increasingly high interest in EONs which are likely to replace WDM as the universally adopted technology in backbone networks in the near future. EONs have two characteristics that may limit its ecient resources use. The spectrum fragmentation, inherent to the dynamic EON operation, decrease the network capacity to assign resources to connection requests increasing network blocking probability. The spectrum fragmentation also intensifides the denial of service to higher rate request inducing service unfairness. Due to the fact EONs were just recently developed and proposed, the aforementioned issues were not yet extensively studied and solutions are still being proposed. Furthermore, EONs do not yet provide specific features as differentiated service mechanisms. Differentiated service strategies are important in backbone networks to guarantee client\'s diverse requirements in case of a network failure or the natural congestion and resources contention that may occur at some periods of time in a network. Impelled by the foregoing facts, this thesis objective is three-fold. By means of developing and proposing a mechanism for routing and resources assignment in EONs, we intend to provide differentiated service while decreasing fragmentation level and increasing service fairness. The mechanism proposed and explained in this thesis was tested in a EON simulation environment and performance results indicated that it promotes beneficial performance enhancements when compared to benchmark algorithms. / Redes backbone s~ao responsáveis pelo transporte de dados à longa distância que atendem a uma grande quantidade de clientes com um grande volume de dados. Como redes backbone devem basear-se em uma rede robusta e de alta capacidade, a tecnologia atual amplamente adotada pela indústria é Wavelength Division Multiplexing (WDM). Redes WDM permitem que uma única fibra opere com múltiplos canais de alta largura de banda, aumentando drasticamente a capacidade da fibra. Em redes WDMcada canal está associado a um comprimento de onda particular. Por conseguinte, toda capacidade do comprimento de onda é atribuída a uma única conexão, fazendo com que parte da largura de banda seja desperdiçada no caso em que a requisição de largura de banda da conexão seja menor do que a capacidade total do canal. A partir da metade da última década, as Redes Ópticas Elásticas (Elastic Optical Networks - EON) têm sido propostas e desenvolvidas com base no uso flexível do espectro óptico conhecido como flexigrid. EONs s~ao adaptáveis às requisições por banda dos clientes e podem, portanto, melhorar o desempenho das redes ópticas. Por estas razões, EONs têm recebido cada vez mais interesse dos meios de pesquisa e provedores de serviço e provavelmente substituirão WDM como a tecnologia universalmente adotada pela indústria em redes backbone. EONs têm duas características que podem limitar a utilização eficiente de recursos. A fragmentação do espectro, inerente à operação dinâmica das EONs, pode diminuir a capacidade da rede em distribuir recursos ao atender às solicitações por conexões aumentando a probabilidade de bloqueio na rede. A fragmentação do espectro também intensifica a negação de serviço a solicitações por taxa de transmissão mais elevada, gerando injustiça no serviço prestado. Como EONs foram desenvolvidas recentemente, respostas às questões acima mencionadas ainda estão sob estudo e soluções continuam sendo propostas na literatura. Além disso, EONs ainda não fornecem funções específicas como um mecanismo que proveja diferenciação de serviço. Estratégias de diferenciação de serviço são importantes em redes backbone para garantir os diversos requisitos dos clientes em caso de uma falha na rede ou do congestionamento e disputa por recursos que podem ocorrer em alguns períodos em uma rede. Impulsionada pelos fatos anteriormente mencionados, esta tese possui três objetivos. Através do desenvolvimento e proposta de um mecanismo de roteamento e atribuição de recursos para EONs, temos a intenção de disponibilizar diferenciação de serviço, diminuir o nível de fragmentação de espectro e aumentar a justiça na distribuição de serviços. O mecanismo proposto nesta tese foi testado em simulações de EONs. Resultados indicaram que o mecanismo proposto promove benefícios através do aprimoramento da performance de uma rede EON quando comparado com algoritmos de referência.

Backbone networks are responsible for long-haul data transport serving many clients with a large volume of data. Since long-haul data transport service must rely on a robust high capacity network the current technology broadly adopted by the industry is Wavelength Division Multiplexing (WDM). WDM networks enable one single ber to operate with multiple high capacity channels, drastically increasing the ber capacity. In WDM networks each channel is associated with an individual wavelength. Therefore a whole wavelength capacity is assigned to a connection, causing waste of bandwidth in case the connection bandwidth requirement is less than the channel total capacity. In the last half decade, Elastic Optical Networks (EON) have been proposed and developed based on the fexible use of the optical spectrum known as the exigrid. EONs are adaptable to clients requirements and may enhance optical networks performance. For these reasons, research community and data transport providers have been demonstrating increasingly high interest in EONs which are likely to replace WDM as the universally adopted technology in backbone networks in the near future. EONs have two characteristics that may limit its ecient resources use. The spectrum fragmentation, inherent to the dynamic EON operation, decrease the network capacity to assign resources to connection requests increasing network blocking probability. The spectrum fragmentation also intensifides the denial of service to higher rate request inducing service unfairness. Due to the fact EONs were just recently developed and proposed, the aforementioned issues were not yet extensively studied and solutions are still being proposed. Furthermore, EONs do not yet provide specific features as differentiated service mechanisms. Differentiated service strategies are important in backbone networks to guarantee client\'s diverse requirements in case of a network failure or the natural congestion and resources contention that may occur at some periods of time in a network. Impelled by the foregoing facts, this thesis objective is three-fold. By means of developing and proposing a mechanism for routing and resources assignment in EONs, we intend to provide differentiated service while decreasing fragmentation level and increasing service fairness. The mechanism proposed and explained in this thesis was tested in a EON simulation environment and performance results indicated that it promotes beneficial performance enhancements when compared to benchmark algorithms. / Redes backbone s~ao responsáveis pelo transporte de dados à longa distância que atendem a uma grande quantidade de clientes com um grande volume de dados. Como redes backbone devem basear-se em uma rede robusta e de alta capacidade, a tecnologia atual amplamente adotada pela indústria é Wavelength Division Multiplexing (WDM). Redes WDM permitem que uma única fibra opere com múltiplos canais de alta largura de banda, aumentando drasticamente a capacidade da fibra. Em redes WDMcada canal está associado a um comprimento de onda particular. Por conseguinte, toda capacidade do comprimento de onda é atribuída a uma única conexão, fazendo com que parte da largura de banda seja desperdiçada no caso em que a requisição de largura de banda da conexão seja menor do que a capacidade total do canal. A partir da metade da última década, as Redes Ópticas Elásticas (Elastic Optical Networks - EON) têm sido propostas e desenvolvidas com base no uso flexível do espectro óptico conhecido como flexigrid. EONs s~ao adaptáveis às requisições por banda dos clientes e podem, portanto, melhorar o desempenho das redes ópticas. Por estas razões, EONs têm recebido cada vez mais interesse dos meios de pesquisa e provedores de serviço e provavelmente substituirão WDM como a tecnologia universalmente adotada pela indústria em redes backbone. EONs têm duas características que podem limitar a utilização eficiente de recursos. A fragmentação do espectro, inerente à operação dinâmica das EONs, pode diminuir a capacidade da rede em distribuir recursos ao atender às solicitações por conexões aumentando a probabilidade de bloqueio na rede. A fragmentação do espectro também intensifica a negação de serviço a solicitações por taxa de transmissão mais elevada, gerando injustiça no serviço prestado. Como EONs foram desenvolvidas recentemente, respostas às questões acima mencionadas ainda estão sob estudo e soluções continuam sendo propostas na literatura. Além disso, EONs ainda não fornecem funções específicas como um mecanismo que proveja diferenciação de serviço. Estratégias de diferenciação de serviço são importantes em redes backbone para garantir os diversos requisitos dos clientes em caso de uma falha na rede ou do congestionamento e disputa por recursos que podem ocorrer em alguns períodos em uma rede. Impulsionada pelos fatos anteriormente mencionados, esta tese possui três objetivos. Através do desenvolvimento e proposta de um mecanismo de roteamento e atribuição de recursos para EONs, temos a intenção de disponibilizar diferenciação de serviço, diminuir o nível de fragmentação de espectro e aumentar a justiça na distribuição de serviços. O mecanismo proposto nesta tese foi testado em simulações de EONs. Resultados indicaram que o mecanismo proposto promove benefícios através do aprimoramento da performance de uma rede EON quando comparado com algoritmos de referência.

Τα σύγχρονα παθητικά οπτικά δίκτυα (PONs) αποτελούν ίσως την πιο σημαντική επιλογή για την ανάπτυξη των μελλοντικών δικτύων ευρυζωνικής πρόσβασης στο παρόν και το μέλλον. Κύριοι λόγοι είναι το χαμηλό κόστος εφαρμογής τους, η απλή λειτουργία τους και υψηλά ποσοστά-ρυθμού μετάδοσης. Τα σύγχρονα Ethernet Passive Optical Networks (EPONs) και η εξέλιξή τους τα Gigabit PON (XGPON) έχουν τυποποιηθεί σε ταχύτητες της τάξεως των 10 Gb/s, ενώ τα επερχόμενα πρότυπα αναμένεται να αυξήσουν τη διαθέσιμη δυναμικότητα τους. Τα EPONs, ειδικότερα, καθιστούν δυνατή τη σύγκλιση των Ethernet δικτύων μεταξύ τους, η οποία βρίσκει ευρεία εφαρμογή σε τοπικά (local) και μέτρo (metro) δίκτυα περιοχής, και την υποδομή οπτικών ινών που εγκαθίσταται εντός του πεδίου εφαρμογής σε fiber-to-the-home (FTTH), την fiber-to-the-building (FTTB) και fiber-to-the-curb (FTTC) δίκτυα. Ακόμα όμως και για πρόσβαση μέχρι τους τελικούς χρήστες. Προτείνουμε ,μέσα από την παρούσα εργασία, μια νέα μέθοδο πρόβλεψης της κυκλοφορίας με σκοπό την ελαχιστοποίηση της καθυστέρησης πακέτων σε Ethernet Passive Optical Networks (EPON). Η μέθοδος βασίζεται στην παρακολούθηση της κυκλοφορίας στο Μονάδων Οπτικού Δικτύου (ONUs) και χρησιμοποιεί τις άμεσα διαθέσιμες πληροφορίες για την κυκλοφορία του δικτύου ώστε να προβλέψει τα δεδομένα που πρόκειται να συσσωρευτούν σε κάθε ONU στον επόμενο κύκλο. Έπειτα από σχετική έρευνα υλοποιήθηκε ο κατάλληλος αλγόριθμος και εξετάστηκε πειραματικά. Τα αποτελέσματα της προσομοίωσης δείχνουν ότι η βελτίωση της καθυστέρησης διάδοσης πακέτων (delay) μειώθηκε πάνω από 25% , χωρίς τροποποίηση του υπάρχοντος αλγορίθμου ανάθεσης εύρους ζώνης. Τέλος αποδείχθηκε η δικαιοσύνη (fairness) του αλγορίθμου στην παροχή πόρων του συστήματος ανάμεσα στις μονάδες ONU. / Modern passive optical networks (PONs) are perhaps the most important choice for the development of future broadband network in the present and the future . Main reason is the low cost of implementation, simple operation and high - transmission rate . Modern Ethernet Passive Optical Networks (EPONs) and the evolution of the Gigabit PON (XGPON) have standardized speeds of 10 Gb / s, while the upcoming standards expected to increase the available capacity . The EPONs, in particular , enable the convergence of Ethernet networks , which finds wide application in locally (local) and metro (metro) area networks , and fiber optic infrastructure installed within the scope of a fiber-to-the -home (FTTH), the fiber-to-the-building (FTTB) and fiber-to-the-curb (FTTC) networks . But even for access to the end users . We propose , through this work , a new prediction method of traffic in order to minimize the delay packets in Ethernet Passive Optical Networks (EPON). The method is based on monitoring the traffic on the Optical Network Units (ONUs) and uses readily available information about network traffic to provide the data to be accumulated at each ONU in the next cycle . After investigation, the appropriate algorithm was implemented and tested experimentally. Simulation results show that the improvement of packet propagation delay (delay) fell over 25 % , without modifying the existing bandwidth assignment algorithm . Finally turned justice (fairness) algorithm in providing system resources between units ONU.

Με την ανάπτυξη της τεχνολογίας οπτικών ινών κατά την τελευταία δεκαετία, η υποδομή των τηλεπικοινωνιών έχει παρουσιάσει μία τρομερή ανάπτυξη στη χωρητικότητα εύρους ζώνης των δικτύων κορμού. Η ανάπτυξη αυτή ξεκίνησε με τα δίκτυα ευρείας περιοχής (WANs) που παρέχουν συνδεσιμότητα μεταξύ πόλεων μέσω των δικτύων μητροπολιτικής περιοχής (MANs), τα οποία συνδέουν τα τηλεπικοινωνιακά κέντρα των παρόχων υπηρεσιών. Ωστόσο, τα δίκτυα πρόσβασης, που εξυπηρετούν πολυάριθμους οικιακούς χρήστες, μικρές επιχειρήσεις και οργανισμούς, δεν έχουν αναπτυχθεί ανάλογα. Παρόλο που η πρόσφατη ανάπτυξη των πρωτοποριακών τεχνολογιών xDSL και CaTV έχει αναβαθμίσει σημαντικά το τμήμα αυτό, οι τεχνολογίες αυτές είναι ακόμη ανεπαρκείς για να καλύψουν την ολοένα και αυξανόμενη ζήτηση εύρους ζώνης των χρηστών. Για την αντιμετώπιση αυτού του προβλήματος, οι τεχνολογίες της οπτικής ίνας μέχρι το σπίτι/το πεζοδρόμιο/το κτίριο (Fiber To The Home/Curb/Building – FTTH/FTTC/FTTB) έχουν θεωρηθεί από καιρό ως μια προτιμώμενη λύση και τα παθητικά οπτικά δίκτυα (PONs) θεωρούνται ευρέως ως μία πολλά υποσχόμενη τεχνολογία για την εφαρμογή διάφορων λύσεων FTTx. Η παρούσα διπλωματική εργασία αρχικά εισάγει το πρόβλημα σχετικά με την ανάγκη εφαρμογής οπτικών δικτύων πρόσβασης. Στη συνέχεια, εξετάζει πιθανές λύσεις στο πρόβλημα αυτό και αναδεικνύει τα παθητικά οπτικά δίκτυα (PONs) ως την καλύτερη επιλογή. Επιπλέον, γίνεται αναφορά στις διάφορες τεχνολογίες πολλαπλής πρόσβασης στα PONs (TDMA, OCDMA και WDMA). Η εφαρμογή της TDMA τεχνολογίας στα PONs αποδεικνύεται η πιο οικονομικά αποδοτική. Για τη χρήση της TDMA τεχνολογίας στα PONs αναπτύχθηκαν τα πρότυπα ATM PON (BPON), Ethernet PON (EPON) και Gigabit PON (GPON). Μετά από σχετική σύγκριση των προτύπων αυτών, το EPON θεωρείται η καλύτερη επιλογή για την εφαρμογή της TDMA τεχνολογίας στα PONs. Αυτή η διπλωματική εργασία στη συνέχεια εισάγει τις θεμελιώδεις έννοιες σχετικά με τα EPONs, εξετάζει τα κύρια ζητήματα που σχετίζονται με τη διάθεση εύρους ζώνης του ανοδικού καναλιού (από τον τελικό χρήστη προς το τηλεπικοινωνιακό κέντρο) στα συστήματα EPONs και παρουσιάζει μία επισκόπηση των πιο πρόσφατων αλγορίθμων δυναμικής διάθεσης εύρους ζώνης (Dynamic Bandwidth Allocation – DBA) για ανοδικές μεταδόσεις στα EPONs. Τέλος, γίνεται περιγραφή και υλοποίηση ενός εκ των πρώτων DBA αλγορίθμων που προτάθηκαν για τη διάθεση του ανοδικού εύρους ζώνης στα EPONs, του αλγορίθμου IPACT (Interleave Polling with Adaptive Cycle Time – IPACT). Κατά την περιγραφή, η limited service του αλγορίθμου IPACT προκύπτει ως η καλύτερη, με βάση διάφορα κριτήρια, μεταξύ των διάφορων υπηρεσιών αυτού του DBA αλγορίθμου και αποτελεί σημείο αναφοράς για μεταγενέστερες δημοσιευμένες εργασίες που υπάρχουν στη βιβλιογραφία. Η υλοποίηση περιλαμβάνει προσομοίωση της limited service του αλγορίθμου IPACT με χρήση της γλώσσας προσομοίωσης SIMSCRIPT II.5 και εξαγωγή αναλυτικών αποτελεσμάτων από εξισώσεις που μοντελοποιούν τη συμπεριφορά του αλγορίθμου, με χρήση της γλώσσας προγραμματισμού C. Τα αποτελέσματα της ανάλυσης και της προσομοίωσης συγκρίνονται και προκύπτουν τα κατάλληλα συμπεράσματα. / With the development of fiber-optic technology over the last decade, the telecommunications infrastructure has shown a tremendous growth in the bandwidth capacity of backbone networks. This development began with the wide area networks (WANs) that provide connectivity between cities through the metropolitan area networks (MANs), which connect service providers’ central offices. However, access networks that serve numerous residential users, small businesses and organizations have not been developed accordingly. Although the recent development of innovative xDSL and CaTV technologies has significantly upgraded this segment, these technologies are still inadequate to meet the ever-increasing bandwidth demand of users. To address this problem, fiber to the home / curb / building (FTTH / FTTC / FTTB) technologies have long been regarded as a preferred solution, and passive optical networks (PONs) are widely regarded as a promising technology for implementing various FTTx solutions. This thesis first introduces the problem concerning the need for optical access networks. Then, examines possible solutions to this problem and highlights the passive optical networks (PONs) as the best option. Furthermore, a reference is made to the various multiple access technologies in PONs (TDMA, OCDMA and WDMA). The implementation of the TDMA technology in PONs proved the most cost-effective. The ATM PON (BPON), Ethernet PON (EPON) and Gigabit PON (GPON) standards have been developed for the use of the TDMA technology in PONs. Upon comparison of these standards, the EPON is considered the best option for the implementation of the TDMA technology in PONs. This thesis then introduces the fundamental concepts on EPONs, examines the major issues related to bandwidth allocation of the upstream channel (from the end user to the central office) in EPONs systems and presents a survey of the most recent dynamic bandwidth allocation (DBA) algorithms for upstream transmissions in EPONs. Finally, a description and an implementation are made of one of the first DBA algorithms proposed for upstream bandwidth allocation in EPONs, the IPACT (Interleave Polling with Adaptive Cycle Time - IPACT) algorithm. In the description, the limited service of the IPACT algorithm emerges as the best among the different services of this DBA algorithm according to various criteria and is a benchmark for subsequent published papers in the literature. The implementation includes the simulation of the limited service of the IPACT algorithm, using the SIMSCRIPT II.5 simulation language and extraction of analytical results from equations modeling the behavior of the algorithm, using the C programming language. The analysis and simulation results are compared and the appropriate conclusions arise.

[pt] O objetivo desta dissertação consiste no desenvolvimento de um analisador de erro para Redes Ópticas através da utilização de circuitos integrados programáveis operando na taxa do Gigabit. As principais fontes de erro, as técnicas de medição da taxa de bits errados e a avaliação de desempenho de enlaces elétricos e ópticos em redes de telecomunicações são descritas e caracterizadas. Dispositivos de transmissão e recepção são desenvolvidos através da introdução de ferramentas computacionais para FPGA colocando-se em evidência o mecanismo de alinhamento e sincronização entre os dois. As simulações e análises destes dispositivos são apresentadas possibilitando a inserção destes em um módulo capaz de avaliar o desempenho de um enlace óptico na taxa de 1.25Gbit/s em função da taxa de bits errados. / [en] The objective of this dissertation consist on development of an error analyzer for Optical Networks by the use of programmable integrated circuits operating in Gigabit rates. The main sources of error, the techniques of BER measurement and the performance evaluation of the electric and optical links in telecommunication networks are described and characterized. Transmission and reception devices are developed through the introduction of computational tools for FPGA giving emphasis to alignment and synchronization mechanism between the two. The simulations and analyses of these devices are presented making possible the insertion of these in a module capable to evaluate the performance of the optical link in the 1.25Gbit/s rate in function of the BER.

As redes ópticas têm evoluído de forma contínua dentro de um paradigma de aumento das taxas de transmissão e extensão dos enlaces, devido à demanda crescente de banda em função do crescimento do tráfego da Internet. Além disso, atualmente, diversas propostas vêm sendo implementadas visando torná-las mais dinâmicas e flexíveis. Uma destas propostas que atualmente está no âmbito de pesquisa e desenvolvimento refere-se às redes ópticas definidas por software (Software Defined Optical Network, SDON). Nas SDONs, o plano de controle é desacoplado do plano de encaminhamento de dados possibilitando que controladores remotos configurem em tempo real diversos parâmetros dos canais ópticos, tais como a taxa de transmissão, o formato de modulação, a largura do espectro, entre outros. Nestas redes, o sistema de controle torna-se bastante complexo, uma vez que diversos parâmetros têm que ser ajustados de forma dinâmica e autônoma, ou seja, com a mínima intervenção humana. O emprego de técnicas de inteligência computacional em tal controle possibilita a configuração autônoma dos parâmetros dos equipamentos com base em dados coletados por monitores de rede e o aprendizado, a partir de eventos passados, visando a otimização do desempenho da rede. Esta arquitetura de controle constitui um novo paradigma na evolução das redes ópticas, as denominadas Redes Ópticas Cognitivas. A escolha de uma técnica de inteligência computacional adequada para tomada de decisão em redes ópticas é importante para se obter vantagens no uso da cognição. Esta técnica deve possibilitar o aprendizado e ainda minimizar a complexidade computacional, uma vez que a configuração dos parâmetros da rede deve ocorrer em tempo real. Neste contexto, esta tese investiga o uso do algoritmo de agrupamento Fuzzy C-Means (FCM) para aprendizado e tomada de decisão em redes ópticas flexíveis de próxima geração. FCM possibilita a geração automática de regras com base na experiência adquirida no meio de operação (aprendizado) e a tomada de decisão a partir destas regras. Uma comparação de desempenho entre os algoritmos FCM e CBR (Case-Based Reasoning) é apresentada. O algoritmo CBR foi escolhido para esta comparação devido a ter sido utilizado recentemente, com sucesso, em redes ópticas cognitivas. Por fim, um conceito de rede óptica cognitiva é apresentado. / Optical networks have evolved continuously increasing the transmission rate and the extension of links due to the increased bandwidth consuming. Moreover, currently, several proposals are under development to make the next generation optical network more dynamic and flexible. The term \"flexible\" refers to the ability of dynamically adjust the parameters of the optical network such as modulation format, transmission rate, optical bandwidth and others, according with the quality of transmission of each lightpath. In this scenario, a Software Defined Optical Network (SDON) emerges as a new optical network paradigm, where the control plane is decoupled from the data plane, enabling remote controllers to configure network equipment from different hardware vendors, which allows a degree of software programmability to the network. In SDON, the control plane needs to include functionalities to operate autonomously, i.e, with minimal human intervention. The use of the computational intelligence techniques in such control plane enables the autonomous operation and learning based on past events, in order to optimize the network performance. This architecture represents a new paradigm in the evolution of optical networks, resulting in so-called Cognitive Optical Networks. The choice of a computational intelligence technique for learning and decisionmaking in such optical networks is essential to bring advantages with the use of cognition. This technique should minimize the computational complexity, since the configuration of the network parameters must occur in real time.In this context, this thesis investigates the use of Fuzzy C-Means clustering algorithm (FCM) for learning and decision-making in the software defined optical networks context. FCM enables the automatic generation of rules, based on the experience gained during the network operation. Then, these rules are used by the control plane to take decisions about the lightpaths\' configuration. A comparison of performance between the FCM and the CBR (Case-Based Reasoning) algorithm. CBR algorithm was chosen because it has been successfully used in cognitive optical networks. Finally, we propose a concept for optical cognitive network.

O principal objetivo deste trabalho é analisar a arquitetura das redes ópticas, discutir o estado da arte dos protocolos necessários ao seu desenvolvimento, e avaliar os vários esforços empregados para a padronização destas por diferentes instituições. Conceitualmente, redes ópticas são aquelas nas quais a tecnologia dominante na camada física é a fibra óptica. Tais redes originaram-se no início dos anos 80 com a utilização dos cabos de fibras ópticas monomodo, tendo evoluído com a introdução de uma nova base tecnológica composta por novos tipos de fibras ópticas, amplificadores ópticos, sistemas DWDM e componentes ópticos, como multiplexadores e demultiplexadores add/drop e cross-connects ópticos. O desenvolvimento destes componentes possibilitará a evolução dos simples enlaces DWDM ponto a ponto para a rede totalmente óptica. Neste trabalho é analisado como as aplicações interagirão com esta camada física. Tal interação tem provado ser um desafio dentro da atual arquitetura das redes de dados, no intuito de disponibilizar soluções que habilitem o transporte de um grande volume de tráfego de forma eficiente. Neste sentido é analisado o emprego de tecnologias como o MPLS (Multiprotocol Label Switching) e sua evolução, o Generalized MPLS (GMPLS). Finalmente apresenta-se a versão do ITU para arquitetura de redes ópticas, e a conseqüente inserção do GMPLS nesta padronização / The main objective of this work is to analyze the evolution trends for the architecture of the optical networks, discuss the state of the art protocols required for its development and evaluate the various efforts being carried out by different institutions in order to achieve standardization. In this context, optical networks are those in which the dominant technology in the physical layer is the optical fiber. Such networks arose in the early eighties with the use of the monomodo fiber optic cables and were further developed with the introduction of a new technological base composed by new types optical fibers, optical amplifiers, DWDM systems and optical components such as add/drop multiplexers and optical cross-connects. The introduction of these components will make possible the evolution from the simple point-to-point DWDM connections to the all optical networks. In this work we analyze how the applications will interact with this physical layer. Such interaction has been proving to be a challenge within the framework for the current architecture of data networks, aiming at offering solutions to enable the transport of a great volume of traffic in an efficient manner. With this goal in mind, the use of technologies such as MPLS (Multiprotocol Label Switching) and its evolution, the Generalized MPLS (GMPLS) is discussed. Finally, we present the ITU version for the architecture optical networks, addressing its merging with the GMPLS

Zhang, Yin. / Thesis submitted in: December 2008. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 56-60). / Abstracts in English and Chinese. / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Telecommunications network hierarchy --- p.2 / Chapter 1.2 --- PON architectures for access networks --- p.4 / Chapter 1.2.1 --- TDM-PON --- p.5 / Chapter 1.2.2 --- WDM-PON --- p.7 / Chapter 1.3 --- Data delivery mode in WDM-PON --- p.8 / Chapter 1.3.1 --- Point-to-point --- p.8 / Chapter 1.3.2 --- Broadcast --- p.9 / Chapter 1.3.3 --- Multicast --- p.10 / Chapter 1.4 --- Motivation of this thesis --- p.10 / Chapter 1.5 --- Outline of this thesis --- p.13 / Chapter Chapter 2 --- Previous Multicast Architectures in WDM-PON --- p.14 / Chapter 2.1 --- Introduction --- p.15 / Chapter 2.2 --- Previous WDM-PON architectures with multicast capability --- p.15 / Chapter 2.2.1 --- Subcarrier multiplexing --- p.16 / Chapter 2.2.2 --- All-optical based multicast enabled architecture --- p.18 / Chapter 2.3 --- Summary --- p.21 / Chapter Chapter 3 --- A Multicast enabled WDM-PON Architecture Using ASK-DPSK Orthogonal Modulation --- p.23 / Chapter 3.1 --- Introduction --- p.24 / Chapter 3.2 --- System architecture --- p.25 / Chapter 3.3 --- Experimental Demonstration --- p.27 / Chapter 3.4 --- Discussion --- p.31 / Chapter 3.5 --- Summary --- p.36 / Chapter Chapter 4 --- A WG filtering and its suppression in quaternary ASK-DPSK based multicast enabled WDM-PON --- p.37 / Chapter 4.1 --- Introduction --- p.38 / Chapter 4.2 --- Principle of narrowband filtering --- p.38 / Chapter 4.3 --- Simulation model --- p.40 / Chapter 4.4 --- Simulation results and discussion --- p.42 / Chapter 4.4.1 --- Different extinction ratios --- p.43 / Chapter 4.4.2 --- Different AWG filter shape and bandwidth --- p.47 / Chapter 4.5 --- Summary --- p.50 / Chapter Chapter 5 --- Summary and Future Works --- p.51 / Chapter 5.1 --- Summary of the thesis --- p.52 / Chapter 5.2 --- Future works --- p.53 / List of Publications --- p.55 / BIBLIOGRAPHY --- p.56

Internet traffic has surpassed voice traffic and is dominating in transmission networks. The Internet Protocol (IP) is now being used to encapsulate various kinds of services. The new services have different requirements than the initial type of traffic that was carried by the Internet network and IP. Interactive services such as voice and video require paths than can guarantee some bandwidth level, minimum delay and jitter. In addition service providers need to be able to improve the performance of their networks by having an ability to steer the traffic along the less congested links or paths, thus balancing the load in a uniform way as a mechanism to provide differentiated service quality. This needs to be provided not only within their domains but also along paths that might traverse more than one domain. For this to be possible changes have been proposed and some are being applied to provide quality of service (QoS) and traffic engineering (TE) within and between domains. Because data networks now carry critical data and there are new technologies that enable providers to carry huge amount of traffic, it is important to have mechanisms to safeguard against failures that can render the network unavailable. In this thesis we propose and develop mechanisms to enable interdomain traffic engineering as well as to speed up the restoration time in optical transport networks. We propose a mechanism, called abstracted path information, that enable peering entities to exchange just enough information to engage in QoS and TE operations without divulging all the information about the internal design of the network. We also extend BGP to carry the abstracted information. Our simulations show that BGP could still deliver the same performance with the abstracted information. In this thesis we also develop a method of classifying failures of links or paths. To improve the restoration time we propose that common failures be classified and assigned error type numbers and we develop a mechanism for interlayer communication and faster processing of signalling messages that are used to carry notification signals. Additionally we develop a mechanism of exchanging the failure information between layers through the use of service primitives; that way we can speed up the restoration process. Finally we simulate the developed mechanism for a 24 node Pan American optical transport network. / <p>QC 20100913</p>

Αντικείμενο της παρούσας διπλωματικής εργασίας αποτελεί η μελέτη της τηλεπικοινωνιακής κίνησης σε οπτικά δίκτυα δρομολόγησης μήκους κύματος. Στα πλαίσια της αποτίμησης της απόδοσής τους, υπολογίζεται η πιθανότητα φραγής κλήσης (Call Blocking Probability) για ένα σύνολο δοσμένων διαδρομών. Αφού αρχικά γίνεται αναφορά στην ιστορία και την εξέλιξη της τεχνολογίας των οπτικών ινών και των οπτικών δικτύων, το θέμα της εργασίας επικεντρώνεται στα οπτικά δίκτυα σταθερής δρομολόγησης και σταθερής εναλλακτικής δρομολόγησης. Γίνεται χρήση δύο αναλυτικών μοντέλων υπολογισμού της πιθανότητας απωλειών σε αυτά: το μοντέλο Birman και το μοντέλο Sridharan-Sivarajan, τα οποία υλοποιούνται στη γλώσσα προγραμματισμού C. Τα αποτελέσματα των μεθόδων ανάλυσης για συγκεκριμένα παραδείγματα συγκρίνονται με αυτά της προσομοίωσης, που υλοποιείται με χρήση της γλώσσας προσομοίωσης SIMSCRIPT II.5. Επιπρόσθετα, εξετάζεται η τεχνική της ομοιοκαταχώρησης τηλεπικοινωνιακής κίνησης (Traffic grooming) με προσομοίωση της λειτουργίας οπτικών δικτύων που κάνουν χρήση της τεχνικής αυτής. / The main objective of this diploma thesis is the study of the telecommunication traffic in Wavelength-Routed Optical Networks. In the frames of their performance evaluation, Call Blocking Probabilities for given routes are calculated. Firstly, the history and evolution of optical fibers and optical networks are described. Followingly, the present thesis is focused in Wavelength-Routed Optical Networks for two routing schemes: Fixed Routing and Fixed Alternate Routing. Two analytical models are used for the calculation of blocking probabilities for these optical networks: Birman model and Sridharan-Sivarajan model, which are realized in C programming language. Afterwards, both these analytical techniques and the simulation, which is realised in SIMSCRIPT II.5 simulation language, are applied in particular examples and their equivalent results are compared. In addition, the Traffic-Grooming technique is examined by simulating the operation of optical networks which use this specific technique.