The main aim of this work was to study the issue of the SNMP protocol and MIB database in order to focus on management and configuration of MIB database using the SNMP protocol. The Master's thesis in detail describes especially creating a communications model of the Manager - Agent type in an OPNET Modeler. In this modeling tool we created exchange of information from the side of the Manager to the side of the Agent via SNMP packets. The Master's thesis is mainly focused on the creation of the SNMP packet according to defined rules, then on reading of information from the MIB database on the side of the Agent and saves this information to the Manager’s MIB database. Exchange of informations is realized via the messages of type GetRequest, GetNext and GetResponse. These models are programmed in language C/C++ and then implemented into the environment of OPNET Modeler.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / This paper discusses simulating iNET's protocol stack using OPNET Modeler. It shows an example of a custom protocol simulated in OPNET Modeler, and how to model the test article, and ground station as reusable components for future simulation. Network simulation is a critical tool for iNET as it enables design decisions that cannot be made analytically due to the complexity of the problem. This work addresses the incorporation of iNET's protocol stack into the OPNET Modeler tool set as this piece of iNET is unique and is not available in OPNET Modeler.

ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / Distributed Denial of Service (DDoS) attacks have been gaining popularity in recent years. Most research developed to defend against DDoS attacks have focused on analytical studies. However, because of the inherent nature of a DDoS attack and the scale of a network involved in the attack, analytical simulations are not always the best way to study DDoS attacks. Moreover, because DDoS attacks are considered illicit, performing real attacks to study their defense mechanisms is not an alternative. For this reason, using packet/network simulators, such as OPNET Modeler, is the best option for research purposes. Detection of an ongoing DDoS attack, as well as simulation of a defense mechanism against the attack, is beyond the scope of this paper. However, this paper includes design recommendations to simulate an effective defense strategy to mitigate DDoS attacks. Finally, this paper introduces network links failure during simulation in an attempt to demonstrate how the network recovers during and following an attack.

The aim of this work is to give information about the structure and elements of the IP Multimedia Subsystem, using signaling protocol and transferring messages between the terminal and elements of IMS. Create model, which implements messages transfer between terminal and IMS elements, by environment tools OPNET Modeler. This work describes system function IMS, its architecture, basic elements, architecture of using signaling protocol SIP and its elements, SIP and SDP messages format and the way of ensuring Quality of Services. There is a project of model terminal registration and reservation data flow by terminal in the IMS. These models were realized in a simulation environment called OPNET Modeler by using tools: project editor, node editor and process editor. In the last part of this work, the method of verification correct function of realized models was created by simulation tools called Debbuger. This tool is one of the environment tools OPNET Modeler.

The differences between networks of mobile operators can be in their achitecture or the optimization of each network. The architecture is standardized which means there will only be differences in the willingness of mobile operators to invest in newer network elements. Network optimization is more important. The way of optimization isn't strictly given and depends on how the operator deals with it. The most important attribute in optimization is balance. The operators try to achieve balance among three important parameters. Those are capacity, coverage and maintaining QoS. Optimization depends on RRM algorithms. The algorithms include various functions such as admission control, congestion control, handover control, power control, etc. These elements don’t only affect the optimization but also affect each other, because they cooperate with each other. For example, an incorrect admission control of the network leads either to frequent network congestion because of a large number of participants in the network (participants are dissatisfied with the services offered by the operator) or to low utilization of the network because of too few participants in the network (the operator is dissatisfied because he is losing the possible earnings). Neither of these posibilities is good for the mobile operator, therefore it is important that the admission control is well balanced.

These times the third generation cellular networks are getting in use increasingly and they dramatically exceed the parameters of second generation networks. Third generation networks are in contrast to older generations data-oriented, providing better maintenance in data and multimedia services. The most widespread third generation network is the UMTS, designed as succesor of GSM network. Master’s thesis is focused on parameters and communication protocols of radio interface of UMTS network. Parameters of radio interface affect the behaviour of mobile terminal through utilization of network services. This thesis describes individual protocols of radio interface and individual procedures, which the mobile terminal have to perform through its staying in the cell. Theoretical part of this thesis considers description of the UMTS network and individual procedures and parameters. Practical part is focused on measuring the radio interface and individual procedures in real UMTS networks. Some procedures are simulated in network simulation software. This thesis includes a lab task focused on this thema.

The diploma thesis gives the overall information about the field of wireless networks of standards 802.11 and Quality of Service (QoS). The practical measurements describe the reactions of multimedia dataflows in the networks 802.11a/b/g/n. The individual standards, offered services, access methods and the network architecture are analyzed in the theoretical part. In the following part there is written about QoS and its basic parameters. Moreover, the standard 802.11e and the question of QoS in the wireless networks are explained in a detailed way. The first part of the practical measurement is focused on the networks 802.11b/g/n. All main network statistics are measured when using the wireless stations and routers. The projection and implementation of the wireless network in the Opnet Modeler is included in the next part. The individual simulations WLAN in the Opnet Modeler are comparing the networks 802.11a/b/g. The analysis of the key QoS statistics is undertaken; the measured data are clearly displayed in the charts and schemes. The interpreted results are concluded and justified.

O Parque Estadual da Cantareira apresenta importância crucial na produção de serviços ambientais e proteção dos remanescentes de Mata Atlântica da Região Metropolitana de São Paulo. Todavia, o crescimento urbano em seu entorno se dá de forma desordenada, gerando pressões e problemas ambientais sobre essa unidade de conservação. Os estudos sobre o crescimento urbano e as análises sobre mudanças no uso e cobertura da terra permitem monitorar estas ao longo do tempo e do espaço e desta forma, indicar possíveis impactos ambientais sobre áreas protegidas. Nesse sentido, esse trabalho teve como objetivo analisar as mudanças do uso e cobertura da terra na área do Parque Estadual da Cantareira e seu entorno no período 1980-2008, além de realizar simulações de cenários futuros para a área. O trabalho foi realizado por meio da utilização de um modelo, o Land Change Modeler LCM e de mapeamentos de uso da terra existentes, associados a variáveis físicas e socioeconômicas para análise específica da expansão urbana no período. A utilização de técnicas de modelagem permitiu a geração de simulações do Uso e Cobertura da terra para o ano de 2035. Temas de restrições às mudanças, como os Parques Estaduais e Municipais existentes e de incentivos às mudanças, como o Rodoanel Mário Covas Trecho Norte, foram adicionados às simulações e possibilitaram a geração de cenários sobre o uso e cobertura da terra futuros. Considerando as limitações do uso de modelos, que são representações simplificadas da realidade, as simulações previstas pelo trabalho podem contribuir para a gestão do Parque Estadual da Cantareira, por meio de sua utilização na revisão de seu plano de manejo, e para as administrações municipais, na elaboração e revisão dos seus planos diretores, o que em última instância, traria benefícios para a amenização das pressões e dos problemas ambientais que incidem sobre essa importante unidade de conservação da Região Metropolitana de São Paulo. / Cantareira State Park has crucial importance in the production of environmental services and for the protection of the Atlantic Forest remnants of São Paulo metropolitan area. However, urban growth occurs in its surroundings in a disorganized way, generating pressures and environmental problems on this protected area. Studies on urban growth and analyses on changes in land use and land cover allow monitoring changes over time and space and in this way show possible environmental impacts on protected areas. Thus, this study aimed to analyze the changes in land use and land cover in the Cantareira State Park area and its surroundings in the period 1980-2008, besides, it carries out simulations of future scenarios for the area. The study was conducted by the use of a model, the Land Change Modeler LCM, and of existing land use mapping associated with physical and socioeconomic variables for specific analysis of urban expansion in the period. The use of modeling techniques allowed the generation of simulations of land use and land cover for the year 2035. Themes of \"restrictions to changes\", as existing \"State and Municipal Parks\", and of \"incentives to changes\", as Northern Section of the Mario Covas Rodoanel, were added to the simulation and enabled the generation of scenarios on future land Use and land Cover. Considering the limitations of the models, which are simplified representations of reality, the simulations provided by the study can contribute to the management of Cantareira State Park, through its use in the review of its management plan and to municipal administrations for preparing and reviewing its Master Plans, which ultimately would benefit the easing of pressures and environmental problems that affect this important conservation unit of São Paulo metropolitan area.

O Parque Estadual da Cantareira apresenta importância crucial na produção de serviços ambientais e proteção dos remanescentes de Mata Atlântica da Região Metropolitana de São Paulo. Todavia, o crescimento urbano em seu entorno se dá de forma desordenada, gerando pressões e problemas ambientais sobre essa unidade de conservação. Os estudos sobre o crescimento urbano e as análises sobre mudanças no uso e cobertura da terra permitem monitorar estas ao longo do tempo e do espaço e desta forma, indicar possíveis impactos ambientais sobre áreas protegidas. Nesse sentido, esse trabalho teve como objetivo analisar as mudanças do uso e cobertura da terra na área do Parque Estadual da Cantareira e seu entorno no período 1980-2008, além de realizar simulações de cenários futuros para a área. O trabalho foi realizado por meio da utilização de um modelo, o Land Change Modeler LCM e de mapeamentos de uso da terra existentes, associados a variáveis físicas e socioeconômicas para análise específica da expansão urbana no período. A utilização de técnicas de modelagem permitiu a geração de simulações do Uso e Cobertura da terra para o ano de 2035. Temas de restrições às mudanças, como os Parques Estaduais e Municipais existentes e de incentivos às mudanças, como o Rodoanel Mário Covas Trecho Norte, foram adicionados às simulações e possibilitaram a geração de cenários sobre o uso e cobertura da terra futuros. Considerando as limitações do uso de modelos, que são representações simplificadas da realidade, as simulações previstas pelo trabalho podem contribuir para a gestão do Parque Estadual da Cantareira, por meio de sua utilização na revisão de seu plano de manejo, e para as administrações municipais, na elaboração e revisão dos seus planos diretores, o que em última instância, traria benefícios para a amenização das pressões e dos problemas ambientais que incidem sobre essa importante unidade de conservação da Região Metropolitana de São Paulo. / Cantareira State Park has crucial importance in the production of environmental services and for the protection of the Atlantic Forest remnants of São Paulo metropolitan area. However, urban growth occurs in its surroundings in a disorganized way, generating pressures and environmental problems on this protected area. Studies on urban growth and analyses on changes in land use and land cover allow monitoring changes over time and space and in this way show possible environmental impacts on protected areas. Thus, this study aimed to analyze the changes in land use and land cover in the Cantareira State Park area and its surroundings in the period 1980-2008, besides, it carries out simulations of future scenarios for the area. The study was conducted by the use of a model, the Land Change Modeler LCM, and of existing land use mapping associated with physical and socioeconomic variables for specific analysis of urban expansion in the period. The use of modeling techniques allowed the generation of simulations of land use and land cover for the year 2035. Themes of \"restrictions to changes\", as existing \"State and Municipal Parks\", and of \"incentives to changes\", as Northern Section of the Mario Covas Rodoanel, were added to the simulation and enabled the generation of scenarios on future land Use and land Cover. Considering the limitations of the models, which are simplified representations of reality, the simulations provided by the study can contribute to the management of Cantareira State Park, through its use in the review of its management plan and to municipal administrations for preparing and reviewing its Master Plans, which ultimately would benefit the easing of pressures and environmental problems that affect this important conservation unit of São Paulo metropolitan area.

Diplomová práce je psána v angličtině a věnuje se standardu IEEE 802.11e, obsahujícím podporu kvality služeb a taky pojednává o kvalitě služeb QoS (Quality of Service) v systému UMTS. Rozebrány jsou hlavní teoretické pilíře daných mechanizmů a praktická část se zabývá simulacemi síťových modelů. Standard 802.11e objasňuje propojení vrstev na fyzické úrovni a zmiňuje metody přístupu k přenosovému médiu DCF, PCF, HCF, EDCA, HCCA. Dále přístupové kategorie a také odlišnosti v MAC podvrstvě, je rozebrána problematika při přenosu prioritních dat na základě identifikátorů. Vzpomenuta je taky struktura formátu rámce a techniky s rozprostřeným spektrem. Časové limity pro doručení prioritních dat a požadavky kladené na tyto data je možné snadno srovnat v tabulkách. Problematika kvality služeb je velice komplexní záležitost, nicméně jsou rozebrány základní klíčové parametry jako koncové zpoždění, jitter, zahazování dat, propustnost, velikost front a hodnota MOS. Zmíněny jsou i mechanizmy integrovaných RSVP a diferencovaných služeb pro zajištění QoS. U systému třetí generace UMTS je objasněna architektura a společná kooperace se systémem GSM. Vzájemné propojení obou sítí je zřejmé z obrázků. Zvýšený zájem je věnován vrstvovému modelu a funkcím RRM pro zajištění QoS. Objasněny jsou různé druhy předávání hovorů, tzv. Handover Control a funkce Admission Control. Rozebrány jsou jednotlivé třídy provozu Conversational, Streaming, Interactive a Background. Praktická část se odehrává v simulačním prostředí programu OPNET Modeler. Byly vytvořeny dva modely s různými scénáři pro srovnání zajištění QoS. Model objasňující princip standardu IEEE 802.11e obsahuje dvě bezdrátové sítě s přístupovými body a stanicemi, na kterých jsou sledovány simulace s různým zatížením přenášených dat. Pro porovnání výsledků je zkoumán rozdíl při použití metody HCF v síti s podporou QoS. Model UMTS sítě obsahuje základnové stanice Node B s možností vysílání do tří sektorů. Mobilní účastník pohybující se po trajektorii představuje princip funkce Softer Handover. Konfrontace mezi scénáři je zastoupena kompresí záhlaví pomocí funkce PDCP a rozlišení Type of Service. Obzvláště je sledováno chování prioritních dat hlasu a videa u obou sítí. Naměřená data zastupují grafy a průběhy výsledních charakteristik. Analýza diskutuje odlišnosti u sítě bez podpory a s podporou kvality služeb. Rozdíly jsou porovnány a vyhodnoceny dle metodiky QoS. Součástí práce je i řešení problémů při návrhu UMTS sítě a podány jsou taky užitečné tipy a návrhy na jejich odstranění. Projekty v simulačním softwaru jsou popsány dle postupu vyhotovení, avšak hloubka podrobností je potlačena. Detaily nejsou rozebírány, protože se očekává pokročilá znalost mechanizmů a jistá dávka zkušeností s programem.