As redes atuais buscam a integração dos serviços e tendem ao IP/MPLS sobre DWDM. No futuro, espera-se que as redes sejam do tipo GMPLS, apresentando melhoria na flexibilidade, capacidade de comutação no meio óptico e também um plano de controle único. Tais redes poderão prover a integração de diferentes camadas e tecnologias, além de reduzirem os custos de operação e de provisionamento. Dentre os muitos aspectos desta nova tecnologia, o trabalho proposto concentra-se no estudo do roteamento óptico em redes GMPLS, verificando a relação existente entre algoritmos RWA e o dimensionamento das mesmas. Pesquisas mostram que, ao tentar estabelecer uma rota numa rede totalmente óptica e com tráfego dinâmico, o bloqueio de conexões e o número de falhas podem limitar o seu desempenho. Realizando-se simulações com algoritmos RWA, é possível determinar o número mínimo de comprimentos de onda e avaliar a melhor topologia de rede para uma determinada probabilidade de bloqueio de conexões e de falhas. Este trabalho mostra como simulações com algoritmos RWA auxiliam no dimensionamento de redes GMPLS permitindo determinar a influência destes algoritmos em seu desempenho. Como principais resultados estão o dimensionamento de recursos, a determinação da carga de tráfego de trabalho e da taxa de falha permitida e a seleção do melhor tipo de algoritmo RWA para a rede de pesquisa Kyatera em duas possíveis fases de sua implementação. / Today's networks seek integration of services and tend towards lean IP/MPLS over DWDM. In the future, it is expected that the networks will tend towards GMPLS with enhanced flexibility and switching capability in the optical layer and a unified control plane. Such networks will provide integration between different network layers and technologies, besides decrease operating and provisioning costs. Among many aspects of this technology, this study concentrates on GMPLS network optical routing, verifying the relationship between RWA algorithms and network dimensioning. Research shows that when attempting to establish a route in an alloptical network with dynamic traffic, connection blocking and failures can limit performance. Through of RWA algorithms simulation, it is possible to determine the minimum wavelength number and check the best network topology for a given probability of connection blocking and failure. This work shows how RWA simulations can assist in the dimensioning of GMPLS networks and in determining the influence of RWA algorithm on their performance. The main results are resource dimensioning, the determination of working traffic load and the allowed failure rate and the selection of the best RWA algorithm for Kyatera research network in two possible phases of its implementation.

As redes atuais buscam a integração dos serviços e tendem ao IP/MPLS sobre DWDM. No futuro, espera-se que as redes sejam do tipo GMPLS, apresentando melhoria na flexibilidade, capacidade de comutação no meio óptico e também um plano de controle único. Tais redes poderão prover a integração de diferentes camadas e tecnologias, além de reduzirem os custos de operação e de provisionamento. Dentre os muitos aspectos desta nova tecnologia, o trabalho proposto concentra-se no estudo do roteamento óptico em redes GMPLS, verificando a relação existente entre algoritmos RWA e o dimensionamento das mesmas. Pesquisas mostram que, ao tentar estabelecer uma rota numa rede totalmente óptica e com tráfego dinâmico, o bloqueio de conexões e o número de falhas podem limitar o seu desempenho. Realizando-se simulações com algoritmos RWA, é possível determinar o número mínimo de comprimentos de onda e avaliar a melhor topologia de rede para uma determinada probabilidade de bloqueio de conexões e de falhas. Este trabalho mostra como simulações com algoritmos RWA auxiliam no dimensionamento de redes GMPLS permitindo determinar a influência destes algoritmos em seu desempenho. Como principais resultados estão o dimensionamento de recursos, a determinação da carga de tráfego de trabalho e da taxa de falha permitida e a seleção do melhor tipo de algoritmo RWA para a rede de pesquisa Kyatera em duas possíveis fases de sua implementação. / Today's networks seek integration of services and tend towards lean IP/MPLS over DWDM. In the future, it is expected that the networks will tend towards GMPLS with enhanced flexibility and switching capability in the optical layer and a unified control plane. Such networks will provide integration between different network layers and technologies, besides decrease operating and provisioning costs. Among many aspects of this technology, this study concentrates on GMPLS network optical routing, verifying the relationship between RWA algorithms and network dimensioning. Research shows that when attempting to establish a route in an alloptical network with dynamic traffic, connection blocking and failures can limit performance. Through of RWA algorithms simulation, it is possible to determine the minimum wavelength number and check the best network topology for a given probability of connection blocking and failure. This work shows how RWA simulations can assist in the dimensioning of GMPLS networks and in determining the influence of RWA algorithm on their performance. The main results are resource dimensioning, the determination of working traffic load and the allowed failure rate and the selection of the best RWA algorithm for Kyatera research network in two possible phases of its implementation.

L’autoritarisme de droite (Right Wing Authoritarianism ; RWA) est une co-variation du conservatisme social, du traditionalisme et de l’autoritarisme. Une des caractéristiques du RWA est une moindre malléabilité des attitudes dans le temps. Cependant, ce lien entre RWA et rigidité des attitudes a été très majoritairement observé dans le cadre de l’étude des relations inter-groupes. Ces études se concentrent sur le lien entre le RWA et le changement d’attitude envers des groupes réels. Si l’intérêt de ces travaux est indéniable, il n’est pas possible d’y examiner la formation et le changement d’attitude de manière contrôlée. En effet, l’étude des groupes sociaux réels implique des effets de contexte ou des préconceptions sociales dans la formation et le changement d’attitude. Dans cette thèse, nous nous intéressons à la compréhension du RWA dans le changement d’attitude au sein d’un cadre standardisé et contrôlé : le conditionnement-contre-conditionnement évaluatif. À travers 11 expériences, nous avons testé si le RWA prédisait un plus faible changement d’attitude envers des stimuli nouveaux et artificiels. Nous avons alors pu observer que le RWA est négativement associé à la sensibilité au contre-conditionnement. Cet effet, présent dans la grande majorité de nos expériences, a été modulé en fonction des caractéristiques du conditionnement-contre-conditionnement. Plus précisément, la quantité d’informations contre-attitudinales disponibles, la présence d’instructions ou encore la diminution des ressources attentionnelles modulent le lien entre RWA et changement d’attitude. Dans l’ensemble, ces résultats corroborent l’hypothèse d’un plus faible changement d’attitude lié au RWA pour des stimuli nouveaux et artificiels. / Right wing authoritarianism (RWA) is a co-variation of social conserva- tism, traditionalism, and authoritarianism. One of the characteristics of RWA is a less malleability of attitudes over time. However, the linkbetween RWA and rigidity of attitudes has mainly been observed in inter- group relation contexts. Such studies focus on the relationship between RWA and attitude change towards real groups. While the value of this work is unde- niable, it is not possible to examine attitude formation and attitude change in a controlled manner. Indeed, studying real social groups implies context effects or social preconceptions on the attitude formation and on attitude change. In this thesis, we are interested in the understanding of RWA in attitude change within a standardized and controlled framework, the evaluative conditioning- counter-conditioning paradigm. Across 11 experiments, we tested whether RWA predicts a lower change of attitude towards new artificial stimuli. We observed that RWA was negatively associated with sensitivity to counter- conditioning. This effect, present in the great majority of our experiments, has been modulated by the characteristics of conditioning-counter-conditioning. More specifically, the amount of counter-attitudinal information available, the presence of instructions, and the decrease in attentional resources were shown to modulate the link between RWA and attitude change. Overall, these results support the hypothesis that a smaller change in attitude is related to RWA even with novel artificial stimuli.

Made available in DSpace on 2014-06-12T17:39:46Z (GMT). No. of bitstreams: 2 arquivo6961_1.pdf: 1602514 bytes, checksum: d3a1132dbb565fa8d43da6001ea39402 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2006 / Esta dissertação demonstra um novo algoritmo de roteamento dinâmico para redes ópticas transparentes baseado nas penalidades da camada física, como o acúmulo de ruído nos amplificadores, a saturação do ganho dos amplificadores e as perdas nos dispositivos ao longo do caminho óptico. A métrica do algoritmo proposto é baseada no cálculo da figura de ruído utilizando-se a formulação bastante conhecida para cascateamento de elementos no caminho óptico. A conversão de comprimentos de onda não é permitida na rede e a alocação dos comprimentos de onda é baseada no algoritmo de First-Fit. Para uma dada chamada o algoritmo atribui o primeiro comprimento de onda disponível e calcula a melhor rota (menor figura de ruído) usando um algoritmo de Dijkstra modificado com a figura de ruído como função custo. Após o cálculo da figura de ruído do caminho óptico a taxa de erro de bit (BER) é determinada. O novo algoritmo bloqueia uma chamada se não existir um comprimento de onda disponível ou se a BER estiver acima do limite pré-definido, o que garante uma qualidade de serviço para o funcionamento da rede. Os resultados de simulações para um tráfego dinâmico numa rede em malha hipotética são apresentados em termos da probabilidade de bloqueio em função da carga da rede e das características dos amplificadores. Mostra-se que o algoritmo proposto é melhor do que o algoritmo de roteamento de menor caminho. O algoritmo é estendido para as redes multifibras

Made available in DSpace on 2014-06-12T15:51:27Z (GMT). No. of bitstreams: 2 arquivo2230_1.pdf: 6593299 bytes, checksum: 3728fcc4b83894390a16239dd5aa05f3 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2009 / Atualmente a tecnologia de redes ópticas transparentes é apontada como a principal infraestrutura para suportar a crescente demanda de tráfego da Internet como também para prover serviços de rede diferenciados para aplicações com exigentes requisitos de qualidade de serviço (por exemplo, aplicações de e-science). Nesse contexto deve ser considerada a existência de uma variedade de perfis de usuários com diferentes requisitos de qualidade. Isso sugere uma provisão de serviços com garantias de qualidade de acordo com as necessidades de cada usuário. É importante, portanto, que os provedores de serviços de telecomunicações disponham de uma metodologia e ferramentas de planejamento para assegurar uma provisão de serviços diferenciada para cada classe de serviço. Tal planejamento é baseado nos requisitos definidos nos contratos de nível de serviço e na necessidade de otimização dos recursos de rede. Esta tese tem como objetivo o desenvolvimento de uma metodologia para o planejamento de redes de circuitos ópticos transparentes com garantia de QoS no nível do usuário

Στα δίκτυα επικοινωνιών, η δρομολόγηση περιλαμβάνει τον προσδιορισμό μιας πορείας μεταξύ των κόμβων της πηγής και του προορισμού για κάθε αίτημα σύνδεσης. Στρέφουμε την προσοχή μας στην κατηγορία των διαφανών (transparent) οπτικών δικτύων όπου, σε απάντηση σε ένα δεδομένο αίτημα κλήσης, εγκαθιδρύεται μια circuit-switched σύνδεση μεταξύ του κόμβου που έχει την απαίτηση κλήσης (πηγή) και του κόμβου που λαμβάνει αυτή την κλήση (προορισμός) σε ένα ενιαίο μήκος κύματος, υπό τον όρο ότι ένα ελεύθερο μήκος κύματος είναι διαθέσιμο σε όλους τους ενδιάμεσου συνδέσμους. Σε ένα διαφανές οπτικό δίκτυο που δρομολογείται βάσει του μήκους κύματος (wavelength routed), η πληροφορία μιας σύνδεσης μεταδίδεται πάνω από αμιγώς οπτικά μονοπάτια (lightpaths) στα οποία το μεταδιδόμενο σήμα παραμένει στο οπτικό πεδίο καθ’ όλη τη διάρκεια της διαδρομής που ορίζεται ανάμεσα στην πηγή και τον προορισμό. Οι παραδοσιακές προσεγγίσεις δρομολόγησης βρίσκουν μια πορεία που είτε ελαχιστοποιεί μια ορισμένη παράμετρο κόστους - όπως το μήκος της σύνδεσης ή των πόρων του δικτύων που χρησιμοποιούνται - ή μεγιστοποιούν την κυκλοφορία που εξυπηρετείται και καλούνται αλγόριθμοι Δρομολόγησης και Ανάθεσης Μήκους Κύματος (Routing and Wavelength Assignment - RWA). Το RWA πρόβλημα εξετάζεται συνήθως κάτω από δύο εναλλακτικές τοποθετήσεις. Η Στατική ή Offline εγκαθίδρυση lightpath που εξετάζει την περίπτωση όπου το σύνολο των συνδέσεων είναι γνωστό εκ των προτέρων και εξυπηρετείται από κοινού. Η Δυναμική ή Online εγκαθίδρυση lightpath εξετάζει την περίπτωση όπου τα αιτήματα σύνδεσης φθάνουν τυχαία χρονικές περιπτώσεις και εξυπηρετούνται ένα προς ένα. Σε αυτήν την μελέτη θα εστιάσουμε στο Online RWA πρόβλημα. Οι περισσότεροι από τους RWA αλγορίθμους υποθέτουν λειτουργία σε ιδανικό φυσικό επίπεδο μετάδοσης όπου μόλις προσδιοριστεί μια διαθέσιμη πορεία και ένα μήκος κύματος, η σύνδεση είναι εφικτή. Όμως στα διαφανή οπτικά δίκτυα, η ποιότητα του σήματος υποβαθμίζεται λόγω εξασθενίσεων (impairments) στο φυσικό επίπεδο που κάνει αδύνατη τη δρομολόγηση (physical-layer blocking). Ως εκ τούτου, απαιτούνται αλγόριθμοι δρομολόγησης που να λαμβάνουν υπ’ όψιν τους περιορισμούς εξασθένισης (impairment aware RWA) προκειμένου να εξασφαλιστεί το γεγονός ότι οι συνδέσεις είναι εφικτές αλλά και με ικανοποιητική ποιότητα μετάδοσης (Quality of Transmission - QoT). Για να γίνει αυτό, είναι απαραίτητο να συνυπολογιστούν τόσο η κατάσταση του δικτύου όσο και η φυσική απόδοση της σύνδεσης. Σε ένα οπτικό δίκτυο που δρομολογείται βάσει του μήκους κύματος το οποίο εκτείνεται σε μεγάλη γεωγραφική περιοχή, ένα οπτικό σήμα μπορεί να μεταβεί σε διάφορους ενδιάμεσους κόμβους και μεγάλα τμήματα ινών. Οι προοδευτικά αυξανόμενες απώλειες του σήματος σε όλους τους ενδιάμεσους κόμβους και τα μεγάλα τμήματα ινών απαιτούν τη χρήση οπτικών ενισχυτών σε στρατηγικές θέσεις στο δίκτυο, ενδεχομένως σε κάθε κόμβο και μέσα στις ίνες, αλλά και Optical Cross Connect Switches (OXC). Δυστυχώς, οι ενισχυτές και οι OXC μπορεί να εισάγουν σημαντικές εξασθενίσεις στη μετάδοση, όπως η παραγωγή crosstalk, ενισχυμένου αυθόρμητου θορύβου (Amplified Spontaneous Emission - ASE), κορεσμού και εξάρτησης από το μήκος κύματος του κέρδους των ενισχυτών, που κάνει το κέρδος μια ποσότητα μη ντετερμινιστική και εξαρτώμενη από την κυκλοφορία της πληροφορίας. Σκοπός της συγκεκριμένης εργασίας είναι να προσδιοριστεί αυτή η σχέση εξάρτησης μεταξύ του κέρδους των ενισχυτών και του μήκους κύματος που χρησιμοποιείται για την εξυπηρέτηση της απαίτησης από τον κόμβο πηγής στον κόμβο προορισμού. Πιο συγκεκριμένα, το κέρδος, με το οποίο ενισχύεται το σήμα κατά τη μετάδοσή του, εξαρτάται από το την ισχύ εισόδου του ενισχυτή, δηλαδή το πλήθος των μηκών κύματος που μπορεί να ενισχύσει ο εκάστοτε ενισχυτής. Επομένως, θέλουμε οι αλλαγές στα κέρδη των ενισχυτών ανάλογα με τo πλήθος των μηκών κύματος που χρησιμοποιούνται σε κάθε κόμβο να συνυπολογίζονται κατά τη διάρκεια εύρεσης των μονοπατιών και της δρομολόγησης των αιτήσεων. Για την επίτευξη αυτού δημιουργήθηκε μια επέκταση ενός ήδη υπάρχοντος αλγορίθμου δρομολόγησης και ανάθεσης μήκους κύματος πολλαπλών κριτηρίων (Multicost Impairment Aware Routing and Wavelength Assignment – IA-RWA) που λαμβάνει υπ’ όψιν του εκτός από τις εξασθενίσεις από το φυσικό επίπεδο κατά τη μετάδοση και τις αλλαγές στα κέρδη των ενισχυτών. Ο προτεινόμενος αλγόριθμος ονομάζεται αλγόριθμος δρομολόγησης και ανάθεσης μήκους κύματος πολλαπλών κριτηρίων με περιορισμούς ισχύος (Multicost Impairment Aware Routing and Wavelength Assignment with Power Constraints – IA-RWA with Power Constraints). Για την εξυπηρέτηση μιας σύνδεσης, βρίσκει μια πορεία και ένα ελεύθερο μήκος κύματος, που να μην επηρεάζει αρνητικά το κέρδος των ενισχυτών της πορείας αυτής, ώστε να έχει αποδεκτή ποιότητα μετάδοσης, βάσει του τρέχοντος βαθμού χρήσης (utilization) του δικτύου, που αλλάζει όσο νέες συνδέσεις εγκαθιδρύονται ή απελευθερώνονται. Ο IA-RWA with Power Constraints αλγόριθμος ακολουθεί τις ίδιες δυο φάσεις ανάπτυξης για την ανάθεση και δρομολόγηση με τον IA-RWA αλγόριθμο. Στην πρώτη φάση, ο αλγόριθμος βρίσκει το σύνολο των επιτρεπτών για την απαιτούμενη QoT πορειών από τη δεδομένη πηγή σε όλους τους κόμβους του δικτύου, συμπεριλαμβανομένου και του προορισμού. Στη δεύτερη φάση, εφαρμόζεται μια συνάρτηση βελτιστοποίησης στο διάνυσμα δαπανών (cost vector) των πορειών, που είναι αυτό που θα πρέπει να κρατά πληροφορίες σχετικές με τις αλλαγές στα κέρδη των ενισχυτών, προκειμένου να βρεθεί η βέλτιστη λύση. Η προσθήκη που επιτυγχάνει το σκοπό μας είναι ο υπολογισμός του κέρδους των ενισχυτών σε όλους τους συνδέσμου του δικτύου πριν την πρώτη φάση του αλγορίθμου αλλά στο τέλος της δεύτερης, όπου εκεί γίνεται ουσιαστικά ένας έλεγχος για τον τρόπο με τον οποίο επηρεάζει η εγκαθίδρυση της νέας αίτησης τις ήδη υπάρχουσες. Με απώτερο στόχο στην περίπτωση της μείωσης του QoT τη φραγή (blocking) ή την επαναδρομολόγηση (rerouting) της αίτησης. Στα Κεφάλαια που θα ακολουθήσουν θα γίνει μια εκτενής παρουσίαση όλων των στοιχείων που συνθέτουν το Online RWA πρόβλημα. Στο Κεφάλαιο 1 θα αναπτυχθεί η τεχνική της Πολυπλεξίας με Διαίρεση Μήκους Κύματος (Wavelength Division Multiplexing - WDM), στο Κεφάλαιο 2 θα περιγραφούν οι φυσικές εξασθενίσεις που συνυπολογίζονται κατά τη διαδικασία της δρομολόγηση και ανάθεσης μήκους κύματος. Στο Κεφάλαιο 3 παρουσιάζονται οι οπτικοί ενισχυτές και ο τρόπος λειτουργίας τους. Στο Κεφάλαιο 4 αναλύουμε τους παράγοντες που βοηθούν στον υπολογισμό της ποιότητας μετάδοσης της πληροφορίας. Τέλος, στα Κεφάλαια 5 και 6 γίνεται η ανάλυση του RWA προβλήματος, του αλγορίθμου που αναπτύχθηκε αλλά και ανάπτυξη των πειραματικών αποτελεσμάτων. / In communication networks, routing involves the identification of a path between the source and destination nodes for each connection request. We focus our attention on the class of transparent optical networks wherein, in response to a given call request, a circuit-switched connection is established between the calling (source) and the called (destination) nodes on a single wavelength, provided a free wavelength is available over the desired lightpath. In a transparent wavelength-routed optical network, the information of connection is transmitted above purely optical paths (lightpaths) in which any transmitted signal remains in the optical domain over the entire route assigned to it between its source and destination nodes. Traditional routing approaches find a path that either minimizes a certain cost parameter - such as the length of the connection or the network resources used – or maximize the traffic served and are called Routing and Wavelength Assignment (RWA) algorithms. The RWA problem is usually considered under two alternative settings. Static or Offline lightpath establishment addresses the case where the set of connections is known in advance and are jointly served. Dynamic or Online lightpath establishment considers the case where connection requests arrive at random time instances and are served on a one-by-one basis. In this study we will focus on the online RWA problem. Most of the RWA algorithms assume an ideal physical layer transmission that once an available path and wavelength have been identified, the connection is feasible. However, in all-optical transparent network, the quality of the signal degrades due to physical layer impairments which make routing unfeasible (physical-layer blocking). Hence, impairment-constraint-based routing is needed in order to ensure that the connections are feasible with acceptable Quality of Transmission (QoT). To do this, it is necessary to consider not only the network-level conditions but also the equally important physical performance of the connection. In a wavelength-routed optical network spanning a large geographical area, an optical signal may traverse a number of intermediate nodes and long fibre segments. The progressive losses incurred by the signal in all intermediate nodes and long fibre segments necessitate the use of optical amplifiers at strategic locations in the network, possibly at each node and within the fibre segments, and optical cross connect switch (XCS). Unfortunately, the XCS and the amplifiers may introduce significant transmission impairments, such as crosstalk generation, generation of amplified spontaneous emission (ASE) noise, saturation and wavelength dependence of amplifiers gain, making the gain a traffic-dependent nondeterministic quantity. Aim of particular work is to determine this relation of dependence between the amplifiers’ gain and the wavelength that is used to serve the request from the source node to the destination node. More concretely, this gain, with which is amplifies the transmission signal, depends on the input power of the amplifiers. Consequently, we want the changes of the amplifiers’ gain, which depend on the number of wavelengths that are used in each node, to be taken into account when requests are routed. For the achievement of this, we created an extension of the Multicost Impairment-Aware Routing and Wavelength Assignment algorithm (IA-RWA) that takes under consideration, apart from the impairments on the physical layer during transmission, the changes of the amplifiers’ gain. The proposed algorithm is called Multicost Impairment Aware Routing and Wavelength Assignment with Power Constraints (IA-RWA with Power Constraints). To serve a connection, the algorithm finds a path and a free wavelength, which does not degrade the amplifier gain of the chosen path, so as to have acceptable quality of transmission (QoT) performance according to the current utilization of the network, which changes as new connections are established or released. The IA-RWA with Power Constraints algorithm follows the same two phases for the routing and wavelength assignment with the IA-RWA algorithm. In the first phase, the algorithm finds the total number of paths with the required QoT, from the given source to all nodes of the network, included the destination. In the second phase, is applied an optimization function in the cost vector of the paths so as to find the most optimal solution. The addition that achieves our aim is the calculation of amplifiers’ gain in all nodes of the network before the first phase of algorithm but also and at the end of the second phase, where substantially checks the way that the establishment of new request influences the already existing. With final objective the blocking of the new connection in the case where the QoT is reduced or the rerouting of the request. In the following Chapters there will be an extensive presentation of all elements that compose Online RWA problem. In Chapter 1 will be developed the technique of Wavelength Division Multiplexing (WDM), in Chapter 2 will be described the physical impairments that are taken under consideration in routing and wavelength assignment procedure. In Chapter 3 are presented the optical amplifiers and their operation. In Chapter 4 we analyze the factors that are used in order to calculate the quality of transmission of a signal. Finally, in Chapter 5 and 6 we analyze the RWA problem, the algorithm that was developed but also the presentation of the experimental results.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Made available in DSpace on 2014-06-12T17:37:09Z (GMT). No. of bitstreams: 2 arquivo5316_1.pdf: 2851435 bytes, checksum: 5945b892d6d58af92090b45f9952e68a (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Nesta dissertação é estudado um importante tópico concernente às redes totalmente ópticas: algoritmos de roteamento e atribuição de comprimentos de onda (RWA). Nas redes totalmente ópticas, o sinal óptico não é regenerado a cada nó. Por isso, é muito importante o desenvolvimento de algoritmos de RWA capazes de encontrar rotas levando em consideração a degradação do sinal óptico, ou seja, algoritmos de IRWA (Impairment Aware Routing and Wavelength Assignment). Neste trabalho são propostas duas novas abordagens para solução do RWA em redes totalmente ópticas. Ambas utilizam parâmetros de redes simples, como comprimento e ocupação de enlace, para montagem de algoritmos de roteamento adaptativos de alto desempenho em ambientes de rede ópticas limitadas pelas penalidades da camada física. Por essa razão, os algoritmos aqui propostos conseguem resolver o problema de IRWA de forma rápida. Na primeira abordagem, denominada PIAWF (Physical Impairment Aware Weight Function), é definida uma nova função custo adaptativa para enlaces que possui dois parâmetros livres, nos quais são armazenados, de forma indireta, informações sobre as penalidades da camada física. Na segunda abordagem, denominada roteamento por série de potência, é elaborada uma forma sistemática de se construir funções de custo adaptativas a partir de parâmetros pré-estabelecidos por um especialista em redes. Estes parâmetros são as variáveis da função custo, a qual é expandida em uma série de potências multivariável. Os coeficientes desconhecidos da série devem ser otimizados com o objetivo de melhorar o desempenho de rede. A técnica Particle Swarm Optimization é utilizada para encontrar os coeficientes da série

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Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal