Over the past few years, many high performance asynchronous transfer mode (ATM) switches have been proposed. The majority of these switches have high performance but also high hardware complexity. Therefore, there is a need for switch designs with low complexity and high performance. This research proposes three new ATM switches based on the folded hypercube network (FHC). The performance of the three architectures are studied using a network model and simulation. The major performance parameters measured are the cell loss rate and cell delay time through the switch under uniform, normal, and bursty traffic patterns. To guarantee faster switching of time-sensitive cells, the routing algorithm of the three switches uses a priority scheme that gives higher precedence to the time-sensitive cells. Also, an output buffer controller is designed to manage the buffers in a fair manner. The three proposed switch architectures have lower complexity while providing equivalent or better switching performance compared to other more complex ATM switches described in the literature. This research shows a new approach to designing ATM switches by using the FHC as the switching fabric for the first time instead of using the crossbar, multi-path, or Banyan-based switching fabrics. / Ph. D.

Asynchronous Transfer Mode (ATM) protocol was designed to support real-time traffic steams over high quality links like fiber optics where the transmission error is extremely low. ATM performs poorly in an error-prone environment such as wireless communications. The purpose of this research is to investigate error control schemes in wireless ATM (W-ATM) to support real-time service, such that the physical layer error conditions are handled in lower layers under ATM transport layer. Automatic Repeat reQuest schemes (ARQ) and Forward Error Correction (FEC) have been widely used for reliable data transmissions. However, the current existing ARQ schemes can potentially introduce unbounded delay in high error rate environments like W-ATM network due to the lack of delay control mechanism. As a result, they are not appropriate for real-time data communications in which there are strict packet delay requirements. In this dissertation, we explored the issues related to W-ATM area. Adaptation of FEC, specifically Reed-Solomon code, to channel error conditions in W-ATM is investigated. The quality-of-service (QoS)-aware error control algorithm is originated and its performance is evaluated. The algorithm is further simplified to make it more suitable for practical applications. The requirements of ARQ applicability for real-time communication environment like W-ATM is extensively analyzed. An ARQ scheme, called D-bit protocol, is developed to satisfy the real-time requirements. The scheme supports reliable packet discarding while allowing retransmissions without compromising user-level QoS for real-time stream applications. Simulations show the effectiveness and liveness of the protocol. / Ph. D.

In this research a suspected "gray" area in computer network performance that might exist between the network's optimum performance and complete network failure was investigated. Changes in performance were studied as seen by the application layer of the network as attenuation was introduced at the physical layer of the network. The network performance was measured for four groups of tests running over TCP and UDP. Various scripts emulating different network applications were used. Ultimately the performance was evaluated at different optical power levels, based on throughput, transaction rate, response time, and lost data. Additionally, the bit error rate characterization of the attenuated optical fiber link was analyzed. Ultimately, performance of the fiber optic ATM-based computer network as seen by the user was correlated with optical power degradation introduced in the physical layer. A decrease in performance was found as attenuation was increased, even in the range of "normal" operating conditions. As expected, TCP, although not immune to soft failures, performed better than UDP. A description of the investigation, tests, scripts, methods and results are included. / Master of Science

Data network resource management and capacity planning are critical for network design, operation, and management. Equipment vendors often provide good information for traffic management and control and associated tools, but this information and the tools are based on independent, individual switches or routers rather than the whole network. There is a critical need for tools to monitor general resource usage in a network as a whole. In this research, we develop a toolkit to collect ATM Call Detail Records (CDRs) from two types of ATM switches from IBM and FORE Systems. Data records collected by the toolkit can then be used to assess network resource utilization and traffic characteristics with the objective of predicting future needs, making proper network management decisions, and ultimately, assisting in the ability to provide reliable quality of service (QoS) in the network. In addition, we examine current call detail records and requirements for more comprehensive network management and make recommendations for a standardized CDR. / Master of Science

Este trabalho aborda o problema decorrente da necessidade de realizar tráfego multicast em redes ATM. Para isto, foi proposta uma arquitetura para a estrutura de célula da chave, mais especificamente a estrutura de roteamento de células no interior da chave ATM. Como o ATM se propõe a atender a todas as exigências do B-ISDN, a necessidade essencial da chave ATM, é que o transporte de células entre suas portas de entrada e saída se faça o mais rápido possível. Para se conseguir isso, a arquitetura proposta não utiliza buffer nos seus elementos de roteamento. O trabalho não implementa no todo a chave ATM, deixando em aberto o problema da perda de seqüência de células no interior da estrutura de roteamento, que seria uma responsabilidade do módulo de saída da chave. A arquitetura proposta foi modelada e um simulador foi construído para a realização dos testes. Para as simulações foram levados em conta os tráfegos de células unicast e multicast. Como as células unicast e as cópias das células multicast disputavam por um mesmo link de saída, foi proposta uma estratégia para separar estas células. Isto resultou no projeto de posicionar a rede de cópia de células no segundo estágio da estrutura de roteamento, deixando o primeiro estágio para o roteamento das células unicast. O resultado disso foi um segundo estágio agora destinado para as cópias de células multicast absolutamente descongestionado, reduzindo \'drasticamente a possibilidade de disputa por um link de saída. Além disso, a estrutura incorpora os conceitos de TBSF (Tandem Banyan Switch Fabric), e duplicidade de rota, que tornam a estrutura extremamente modular e flexível. Para atender a preocupação em separar o tráfego, foi introduzido entre um estágio e outro da rede Banyan, uma saída de fuga, permitindo que células que tenham atingido a porta de saída desejada possam deixar a estrutura. São apresentados os resultados da simulação, objetivando a validação do trabalho proposto. / This thesis addresses the problem of accomplishing multicast traffic in ATM networks. An architecture is proposed for the cell structure of the switch, more specifically the routing of cells inside an ATM switch. Because ATM tries to satisfy all the demands of the B-ISDN model, an ATM switch must transport cells between its input and output ports as fast as possible. To achieve that, the proposed architecture does not use buffers in its commutation elements. This work does not implement a complete ATM switch, leaving the problem of the loss of sequence of cells inside the routing structure open. This problem must be solved by the output module of the switch. The proposed architecture was modeled and a simulator was built for testing purposes. For the simulations, both the unicast and the multicast traffic were taken into account. As the unicast cells and the copies of the multicast cells disputed for the same output link, a strategy was proposed to separate these cells. This resulted in the positioning of the cell copy network in the second stage of the routing structure, leaving the first stage for the routing of unicast cells. The result was a very free second stage used for copying multicast cells. This new stage reduced the contention for an exit link. The structure incorporates the concepts of TBSF, and route duplicity, which make it extremely modular and flexible. To separate the traffic, it was introduced between the two stages of the Banyan Network an escape exit, allowing cells that have reached the correct output port to leave the structure.

Made available in DSpace on 2016-08-10T10:38:35Z (GMT). No. of bitstreams: 1 Hellen da Silva Cintra de Paula.pdf: 4823796 bytes, checksum: 7a1015ff712efd961fb8cb5dfd8ad2ef (MD5) Previous issue date: 2012-03-14 / The purpose of this study was to evaluate the association of single nucleotide polymorphisms of ATM and TP53 genes in prostate cancer patients with skin, urinary and lower gastrointestinal systems morbidity after radiotherapy. These two genes encode important proteins of the DNA repair pathways. It is believed that their polymorphisms are likely to modify the response of normal tissues to radiation. A group of 50 patients of the Radiotherapy Service at Araújo Jorge Hospital (Associação de Combate ao Câncer em Goiás) was selected. After signing the informed consent agreement, a sample of peripheral blood was collected for subsequent DNA extraction and polymerase chain reaction (PCR) for amplification of ATM and TP53 gene fragments. Finally the amplified fragments were sequenced to verify the presence of an exchange G> A in the codon 1853 of the ATM gene and polymorphisms of TP53 gene (C> G in the codon 72, C>T in the codon 47, C>A in the position 11299, C>T in the position 11322 and one insertion of 16 base pairs in intron 3). The side effects were classified according to the Radiation Therapy Oncology Group (RTOG) score. On univariate analysis, hypertension was strongly associated with a decreased risk of late urinary toxicities (OR= 0,048, 95% CI 0,004 - 0,620; p= 0,022). Patients receiving hormone therapy had a significantly higher incidence of acute skin toxicity (RR=1,286, 95% CI 0,907 - 1,823; p = 0,029). The exchange C>T in the position 11322 of the TP53 gene (intron 3) was significantly associated with the risk of acute skin toxicity (RR=22,0, 95%CI 5,680 - 85,207; p=0,006). There wasn t association between the other TP53 and ATM polymorphisms analysed and the frequency of side effects (p>0,05). In this study it has been shown that the presence of hypertension seemed to be protective for the development of urinary late effects after radiotherapy. Hormone therapy was apparently determinant for the development of acute skin toxicity. Our data also revealed that a TP53 intronic polymorfism (11322 C>T) was associated to increased acute skin radiosensitivity. This observation corroborates the importance of investigating the genetic profile to predict adverse side effects in patients undergoing radiotherapy. / O propósito deste estudo foi avaliar a associação entre polimorfismos de base única nos genes ATM e TP53 em pacientes com câncer prostático e a morbidade na pele e nos sistemas urinário e gastrointestinal inferior após a radioterapia. Estes dois genes codificam proteínas importantes nas vias de reparo do DNA. Acredita-se que seus polimorfismos possam modificar a resposta do tecido normal a radioterapia. Foi selecionado um grupo de 50 pacientes do serviço de radioterapia do Hospital Araújo Jorge (Associação de Combate ao Câncer em Goiás). Após a assinatura do termo de consentimento livre e esclarecido, foi coletada a amostra de sangue periférico com subseqüente extração de DNA e amplificação gênica por meio de reação em cadeia da polimerase (PCR) para amplificar os fragmentos gênicos de ATM e TP53. Finalmente, os amplicons foram seqüenciados para verificar a presença da troca de G>A no códon 1853 do gene ATM e polimorfismos do gene TP53 (C>G no códon 72, C>T no códon 47, C>A na posição 11299, C>T na posição 11322 e uma inserção de 16 pares de bases no intron 3). Os efeitos adversos foram classificados de acordo com o escore do Radiation Therapy Oncology Group (RTOG). Por meio de análise univariada, a hipertensão se associou fortemente ao baixo risco de desenvolvimento de toxicidade urinária crônica (OR=0,048, 95%IC 0,004 - 0,620; p=0,022). Pacientes que foram submetidos à hormonioterapia mostraram uma incidência significativa de toxicidade de pele aguda (RR = 1,286, 95%IC 0,907 1,823; p=0,029). A troca C>T na posição 11322 do gene TP53 (intron 3) mostrou uma associação significativa com o risco de toxicidade aguda de pele (RR = 22,0, 95%IC 5,68 85,207; p=0,006). Não houve associação entre os outros polimorfismos de TP53 e ATM analisados e a freqüência de efeitos adversos (p>0,05). Foi demonstrado que a presença de hipertensão parece ser protetora para o desenvolvimento de efeitos urinários tardios após a radioterapia. A hormonioterapia foi aparentemente determinante no surgimento de toxicidade aguda de pele. Nossos dados revelaram ainda que um polimorfismo intrônico de TP53 (11322 C>T) também estava associado ao aumento de radiossensibilidade aguda de pele. Estas observações mostram a importância de se investigar o perfil genético para futuramente predizer os efeitos adversos de pacientes em radioterapia.

Made available in DSpace on 2016-08-10T10:38:45Z (GMT). No. of bitstreams: 1 Cristiana da Costa Luciano.pdf: 1987242 bytes, checksum: 2f3402c7b9c457e5f89de59897be59ea (MD5) Previous issue date: 2012-11-14 / The head and neck cancer is the fifth most common in Brazil, being the most predominant histology type the squamous cell carcinoma. Radiation therapy is a procedure for treatment with the efficacy variable, and may play an important role in controlling tumor growth. Faced with this therapy, the patient is exposed to ionizing radiation that can cause adverse effects resulting cessation of treatment. The objective was to evaluate the association of polymorphisms of TP53 and ATM genes in patients with head and neck cancer with adverse effects on normal tissues presented as a result of radiotherapy. Materials: The DNA was extracted 54 samples of peripheral blood of patients with head and neck cancer, then the fragments of TP53 and ATM were amplified and subsequently sequenced to check for any polymorphism which may be responsible for the radiosensitivity of patients. Statistical analysis was performed using the SPSS 17.0 software. Results and Discussion: In univariate analysis, patients who had experienced adverse effects RT suspended acute low and high grade with RTOG skin (p = 0.012). Those who had a family history of cancer showed higher adverse acute laryngeal RTOG TGI high (p = 0.040). The exchange C> T at position 11322 of TP53 (intron 3), the ATM and TP53 polymorphisms analyzed and the frequency of acute and chronic adverse effects were not significant (p>05). Conclusions: Based on these results is of utmost importance that alternatives are created to predict the dose to be prescribed during radiotherapy, preventing adverse effects and discontinuation of treatment and also providing better tumor control. / O câncer de cabeça e pescoço, no Brasil, é o quinto mais comum, sendo o tipo histológico mais predominante de carcinoma de células escamosas. A radioterapia é uma das modalidades de tratamento com eficácia variável, podendo desempenhar um papel importante no controle do tumor. Diante essa terapêutica, o paciente está exposto a radiações ionizantes que podem causar efeitos adversos gerando a interrupção do tratamento. O objetivo foi avaliar a associação de polimorfismos dos genes TP53 e ATM em pacientes com câncer de cabeça e pescoço com efeitos adversos sobre os tecidos normais apresentados como resultado da radioterapia. Materiais: O DNA foi extraído de 54 amostras de sangue periférico de pacientes com câncer de cabeça e pescoço, em seguida os fragmentos de TP53 e ATM foram amplificados e posteriormente sequenciados a fim de verificar se os polimorfismos poderiam estar associados à radiossensibilidade dos pacientes selecionados. A análise estatística foi realizada utilizando o software SPSS 17.0. Resultados e Discussão: Por meio de análise univariada, pacientes que tiveram a RT suspensa apresentaram efeitos adversos agudo de baixo e alto grau com RTOG de pele (p=0,012). Aqueles que tinham história familiar de câncer apresentaram maiores efeitos adversos agudo de laringe com RTOG TGI alto (p=0,040). A troca C>T na posição 11322 do gene TP53 (intron 3), os polimorfismos de TP53 e ATM analisados e a frequência de efeitos adversos agudos e crônicos não foram significativos para (p>0,05). Conclusões: Diante dos resultados obtidos é de suma importância que alternativas sejam criadas para predizer a dose a ser prescrita durante a radioterapia, prevenindo os efeitos adversos e a interrupção do tratamento e ainda, promovendo melhor controle tumoral.

Made available in DSpace on 2016-08-10T10:38:48Z (GMT). No. of bitstreams: 1 JOAO LINO FRANCO BORGES.pdf: 1554450 bytes, checksum: 2c0f4d5c22814fcc52394573bf4f06f6 (MD5) Previous issue date: 2014-03-28 / The purpose of this study wasto evaluate the association of single nucleotide polymorphisms of ATM and TP53 genes in breast cancer patients with skin and subcutaneous systems morbidity after radiotherapy. These two genes encode important proteins of the DNA repair pathways. It is believed that their polymorphisms are likely to modify the response of normal tissues to radiation. A group of 78 patients of the Radiotherapy Service at Araújo Jorge Hospital (Associação de Combate ao Câncer em Goiás) was selected. After signing the informed consent agreement, a sample of peripheral blood was collected for subsequent DNA extraction and polymerase chain reaction (PCR) for amplification of ATM and TP53 gene fragments. Finally the amplified fragments were sequenced to verify the presence of an exchange G> A in the codon 1853 of the ATM gene and polymorphisms of TP53 gene (C> G in the codon 72). The side effects were classified according to the Radiation Therapy Oncology Group (RTOG) score. On univariate analysis,the expected effects of treatment with RT events showed that there was a significant association between aboost RT and its suspension with the acute effects of high-grade skin (OR = 3.05, 95% CI 1.175 to 7.928, p = 0.035) (OR = 3.808, 95% CI 1.213 to 11.958, p = 0.033), respectively. Side effects of acute high-grade skin were associated with a longer duration of treatment. (p=0.01 IC95% -11.546 - (-1,638). The type of surgery was significantly associated with late subcutaneous tissue (OR = 1.326, 95% CI 1.143 to 1.537, p = 0.016) side effects There was no association between polymorphisms TP53 and ATM analysed with acute and late side effects of skin nor subcutaneous tissue (RTOG ≥ 2) (p> 0.05). / O propósito deste estudo foi avaliar a associação entre polimorfismos de base única nos genes ATM e TP53 em pacientes com câncer de mama e a morbidade na pele após a radioterapia. Estes dois genes codificam proteínas importantes nas vias de reparo do DNA. Acredita-se que seus polimorfismos possam modificar a resposta do tecido normal a radioterapia. Foi selecionado um grupo de 78 pacientes do serviço de radioterapia do Hospital Araújo Jorge (Associação de Combate ao Câncer em Goiás). Após a assinatura do termo de consentimento livre e esclarecido, foi coletada a amostra de sangue periférico com subsequente extração de DNA e reação em cadeia da polimerase (PCR) para amplificar os fragmentos gênicos de ATM e TP53. Finalmente, os fragmentos amplificados foram sequenciados para verificaçãoda presença da troca de G>A no códon 1853 do gene ATM e polimorfismos do gene TP53 (C>G no códon 72). Os efeitos adversos foram classificados de acordo com o escore do Radiation Therapy Oncology Group (RTOG). Por meio de uma análise univariada, os eventos esperados do tratamento com RT mostraram que houve uma associação significativa entre o reforço da RT e a sua suspensão com os efeitos agudos de alto grau da pele (OR=3.05, IC95% 1,175-7,928, p=0,035) (OR=3.808, IC95% 1,213-11,958, p=0,033), respectivamente. Os efeitos colaterais agudos de alto grau na pele se associaram a um tempo maior de duração de tratamento. (p=0.01 IC95% -11.546- (-1,638). O tipo de cirurgia se associou significativamente aos efeitos colaterais tardios do tecido subcutâneo (OR=1,326, IC95% 1,143-1,537, p=0,016). Não houve associação entre os polimorfismos de TP53 e ATM analisados com os efeitos colaterais agudos e tardios de pele, nem tampouco do tecido subcutâneo(RTOG≥2) (p>0,05).

Esta dissertação descreve os métodos, medidas e análises feitas para otimizar a rede de comunicação de dados do Instituto de Física de São Carlos. As tecnologias e protocolos utilizados na rede são apresentados. Especial atenção é dada a análise do desempenho de VLANs utilizando inicialmente o protocolo LANE no núcleo ATM da rede. Neste caso a rede é composta de switches ATM e ATM-Ethernet. Medidas comparativas foram realizadas com a utilização da tecnologia Fast Ethernet no backbone, que possui uma capacidade de transmissão relativamente próxima da ATM de 155Mbps. Melhores resultados obtidos com a implementação de sub-redes maiores, reduzindo em um numero menor de sub-redes, são discutidos e apresentados. Análises estatísticas baseadas apenas no tempo de resposta da rede são apresentados para avaliar o desempenho das alterações efetuadas nas configurações da rede. Mesmo que o tráfego tenha aumentado muito durante esses anos e que vários serviços tenha sido agregados a esta rede, foi possível adequar o desempenho as novas necessidades beneficiando-se da evolução tecnológica que os equipamentos de rede de dados trouxeram ao IFSC. / This work describes the methods, measures and analyses performed aiming to optimize the data communication network from the Physics Institute of Sao Carlos as well as the technologies and protocols used in the network recently. Special care is given to the analysis of the VLANs performance using, initially, the LANE protocol over ATM which has its core based on pure ATM and ATM-Ethernet switches. Comparative measures had been carried out using a backbone working on a Fast Ethernet technology, which seems to have a very close transmission rate from the ATM 155Mbps. This work also discusses best results acquired with the implementation of larger networks reducing the number of subnetworks, statistical analyses based on time delay of the network in order to evaluate the performance of the changes made on its configuration. Even though the traffic from the Institute has been increased over these years and several services have been added to the network, it was completely possible to adapt the performance to the needs, using the benefits of the technological evolution which the network equipments had brought to the Institute.

O processo de dimensionar redes de comunicação tem sido um desafio para pesquisadores e projetistas. A partir da especificação, passando pela operação, controle e gerenciamento de redes, as estimativas de comportamento do desempenho são úteis para o dimensionamento adequado dos equipamentos. O detalhamento e precisão na capacidade de avaliar o impacto de carga futura melhoram as chances de prever dificuldades em atingir metas de serviços. Com redes de banda larga, como ATM, não tem sido diferente. Pela sua concepção de oferecer garantia de qualidade para serviços com diferentes requisitos, ATM se empenha em evitar a sobrecarga da rede. De início, essa premissa é preservada naturalmente através da restrição da quantidade e tipo de conexões ingressas na rede. Portanto, a adequação dos recursos que compõem a estrutura de uma rede ATM determina o grau de disponibilidade em atender certa quantidade de serviços. A pergunta que desejamos responder é: como estimar com precisão a quantidade de serviço suportada por determinada rede ATM? O limite da rede é alcançado quando os recursos disponíveis são menores que os recursos necessários à carga de serviço. Com o emprego cada vez maior de ATM por empresas de telecomunicações, conhecer o limite da rede é estar ciente da potencialidade de negócios sem comprometimento da qualidade. É poder prever expansões evitando bloqueio de novos serviços. O processo de dimensionamento de capacidade de uma rede ATM revela a quantidade de recursos necessários para suportar determinada carga de serviço. Quando os recursos necessários forem maiores que os recursos disponíveis, o limite da rede foi alcançado. Nesse caso, são duas as possibilidades para o equilíbrio: aumentar os recursos da rede ou diminuir a carga de serviço desejado. Esta dissertação propõe um método para dimensionamento dos recursos de uma rede ATM. A principal técnica empregada no método é a simulação do comportamento de tráfego sobre comutadores ATM. Para determinada carga de tráfego são executadas diferentes simulações variando os recursos disponíveis dentro de parâmetros prováveis. As seguintes medidas de desempenho são obtidas nas simulações como resultados estatísticos médios: razão de perda de células (CLR), atraso de transferência de células (CTD) e variação do atraso de células (CDV). Conhecendo o desempenho desejado (QoS) pela carga de serviço, o método pode determinar a quantidade necessária de recursos que satisfazem os requisitos de QoS. A ferramenta escolhida para implementar o modelo foi o simulador orientado a eventos ATM/HFC do National Institute of Standards and Technology (NIST). O simulador é composto por diferentes modelos de elementos, cada qual com seus atributos, que podem ser combinados para caracterizar determinadas configurações de rede que se deseja avaliar. Os elementos podem ser desde representações de tipos de comutadores ATM até diferentes técnicas de controle de tráfego a serem utilizadas na simulação. A carga de serviço na simulação é provida por elementos modeladores que caracterizam diferentes tipos de aplicações geradoras de tráfego, permitindo arranjos de serviços CBR, VBR, ABR e UBR através de seus respectivos parâmetros descritores. A validação do método é efetuada através da comparação dos resultados obtidos com outro trabalho similar desenvolvido utilizando simulação. / The process of planning communication networks has been a challenge for researchers and designers. From the specification, through the operation, control and management of networks, the behavior performance estimates are useful for the adequate equipment dimensioning. The detailing and accuracy in the capacity to evaluate the future load impact increase the possibilities to forecast difficulties in reaching goals of services. With broadband networks, as ATM, it has not been different. ATM efforts in preventing network overload by its conception to offer quality guarantee for services with different requirements. From beginning, this premise is naturally preserved through restriction of the amount and type of connections that can enter the network. Therefore, the adequacy of the resources that compose the ATM network structure determines the degree of availability in attending certain amount of services. The question that we wish to answer is: how can we estimate accurately the amount of services supported by specific ATM network? The limit of the network is reached when the available resources are below the necessary resources to service load. With the higher use of ATM for telecommunications companies, to know the limit of network is to be aware of the potentiality without damage to the quality. It's to be able to forecast expansions to prevent new services blocking. The capacity planning process of an ATM network shows the amount of resources needed to support a specific workload. When the resource need is greater than the available resource, the network limit has been reached. In this case, there are two possibilities to reach balance: increase the network resources or lower the load of desired service. This work is about a method for ATM network resources dimensioning. The main technique used in the method is the traffic behavior simulation over ATM switches. For specific workload, different simulations are executed and they vary according to the resources available inside the probable parameters. The following measures of performance are gotten in the simulations as average statistics results: cell loss ratio (CLR), cell transfer delay (CTD) and cell delay variation (CDV). Knowing the workload desired performance (QoS), the method can determine the necessary amount of resources that will satisfy the QoS requirements. The chosen tool to implement the model was the event driven simulator ATM/HFC of the National Institute of Standards and Technology (NIST). The simulator is made up of different models of elements, each one with its attributes, which can be combined to characterize specific network configurations that are to be evaluated. The elements can range from representations of types of ATM switches to different techniques of traffic management to be used in the simulation. The workload in the simulation is provided by modeler elements that characterize different types of traffic generator applications, allowing sets of CBR, VBR, ABR and UBR services through their respective traffic parameters. The method validation is carried out through the matching of the results gotten with other similar work developed using simulation.