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Warsama, Ahmed. "Traffic Engineering with SDN : Optimising traffic Load-Balancing with OpenFlow". Thesis, Mittuniversitetet, Institutionen för informationssystem och –teknologi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-39385.
Повний текст джерелаАнотація:
The advent of trends such as virtualization, cloud computing, IoT and BYOD has increased the traffic loads on modern enterprise and data-center networks. As the requirements on today’s networks increase, newer designs and solutions have sprout forth. Software-Defined Networking was developed to cater to the needs of modern networks and to improve traffic handling among other things. This study focuses on the ways SDN, specifically the OpenFlow standard, can be used to load-balance and increase the network throughput, in comparison to traditional methods such as Equal-Cost Load-Balancing. This was done by creating a test environment with the network emulator Mininet, and by creating load-balancing programs. The load-balancers were created using the OpenFlow protocol. These programs were used together with the Floodlight controller and were compared in the same environment. The results showed that the bandwidth load-balancer outperformed the Equal-Cost Load-Balancer.
2
Wang, Xuan. "A Load Balancing Algorithm for Flow Management in Hybrid-SDN Networks." Thesis, University of South Dakota, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10937380.
Повний текст джерелаАнотація:
Hybrid Software Defined Network(Hybrid-SDN) is the most popular topic in recent years, with related development and deployment of vendors of software and hardware. HybridSDN has the capabilities of most advantaged technology and features with the network current on use in public. However, the Hybrid-SDN does not have the highest performance which is the pure SDN network architecture. It is necessary for researchers understand the differences between legacy network, SDN and Hybrid-SDN, through the numeric comparison of performances by simulations. Also, as the cooperation part between the legacy nodes and SDN nodes in Hybrid-SDN network architecture, load balancing algorithm played an important role. There are lots of load balancing algorithm comes out since the network architecture first time constructed. But the different between load balancing algorithms are not clear. It is necessary for researchers know is there existing difference between load balancing algorithms. Also, particular for Hybrid-SDN network architecture, the messed up environment of different type of devices, the current existing load balancing algorithm did not considering all the cases may affect the network. The solution for the problem is to design a load balancing algorithm which particular focusing on Hybrid-SDN environment. To explain the differences of these framework and design the load balancing algorithm, we studied different network architectures and load balancing algorithms, evaluated them by simulation results. The main work included the following tasks:
• Simulated three network architectures. • Simulated two common load balancing algorithms. • Designed a load balancing algorithm for flow management focus on Hybrid-SDN
The simulation results of three network architectures provided the clearly differences between these architectures, which approve the Hybrid-SDN has a big performance promotion with Legacy Network. The results of two load balancing algorithms showed there existing difference between load balancing algorithms, so that, it is necessary to have a load balancing algorithm particular focusing on Hybrid-SDN. And both analysis and simulation results dedicated that our proposed load balancing algorithm can perform efficiently for Hybrid-SDN network architecture.
3
Marciniak, Petr. "Vyvažování zátěže v sítích OpenFlow." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2013. http://www.nusl.cz/ntk/nusl-236205.
Повний текст джерелаАнотація:
The aim of this thesis is to develop a load balancing tool for OpenFlow networks. Software-defined networking (SDN) principles are introduced (OpenFlow protocol used as an example) and compared to the legacy routing and switching technology. Openflow is the first protocol/API enabling communication between the control and infrastructure planes of the software-defined networking model. Key features of the protocol are described and several OpenFlow controllers are introduced. Current best practices in computer networks load balancing are discussed as well. The load balancing application development process is described including the test laboratory setups - Mininet (SW) and OFELIA (HW). The application test results are evaluated and possible further enhancements to the program are discussed.
4
Sehery, Wile Ali. "OneSwitch Data Center Architecture." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/94376.
Повний текст джерелаАнотація:
In the last two-decades data center networks have evolved to become a key element in improving levels of productivity and competitiveness for different types of organizations. Traditionally data center networks have been constructed with 3 layers of switches, Edge, Aggregation, and Core. Although this Three-Tier architecture has worked well in the past, it poses a number of challenges for current and future data centers.
Data centers today have evolved to support dynamic resources such as virtual machines and storage volumes from any physical location within the data center. This has led to highly volatile and unpredictable traffic patterns. Also The emergence of "Big Data" applications that exchange large volumes of information have created large persistent flows that need to coexist with other traffic flows. The Three-Tier architecture and current routing schemes are no longer sufficient for achieving high bandwidth utilization.
Data center networks should be built in a way where they can adequately support virtualization and cloud computing technologies. Data center networks should provide services such as, simplified provisioning, workload mobility, dynamic routing and load balancing, equidistant bandwidth and latency. As data center networks have evolved the Three-Tier architecture has proven to be a challenge not only in terms of complexity and cost, but it also falls short of supporting many new data center applications.
In this work we propose OneSwitch: A switch architecture for the data center. OneSwitch is backward compatible with current Ethernet standards and uses an OpenFlow central controller, a Location Database, a DHCP Server, and a Routing Service to build an Ethernet fabric that appears as one switch to end devices. This allows the data center to use switches in scale-out topologies to support hosts in a plug and play manner as well as provide much needed services such as dynamic load balancing, intelligent routing, seamless mobility, equidistant bandwidth and latency.PHD
5
Nguyen, Van-Giang. "Towards SDN/NFV-based Mobile Packet Core : Benefits, Challenges, and Potential Solutions." Licentiate thesis, Karlstads universitet, Institutionen för matematik och datavetenskap (from 2013), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-67132.
Повний текст джерелаАнотація:
In mobile networks, the mobile core plays a crucial role in providing connectivity between mobile user devices and external packet data networks such as the Internet. Through the years, along with the dramatical changes in radio access networks, the mobile core has also been evolved from being a circuit-based analog telephony system in its first generation (1G) to become a purely packet-based network called the Evolved Packet Core (EPC) in the current generation (4G). In recent years, the explosion of mobile data traffic and devices and the advent of new services have led to the investigation of the next generation of mobile networks, i.e., 5G. A wide range of technologies has been proposed as candidates for the development of 5G. Among other technology candidates, Software Defined Networking (SDN) and Network Function Virtualization (NFV) have been widely considered to be key enablers for the network architecture of 5G, especially the mobile packet core (MPC) network. This thesis aims at identifying benefits and challenges of introducing SDN and NFV to re-achitect the current MPC network architecture towards 5G and addressing some of the challenges. To this end, we conduct a comprehensive literature review of the state-of-the-art work leveraging SDN and NFV to re-design the 4G EPC architecture. Through this survey work, several research questions for future work have been identified and we contribute to address two of them in this thesis. Firstly, since most of the current works focus on unicast services, we propose an SDN/NFV-based MPC architecture for providing multicast and broadcast services. Our numerical results show that the proposed architecture can reduce the total signaling cost compared to the traditional architecture. Secondly, we address the question regarding the scalability of the control plane. We take the Mobility Management Entity (MME) - one of the EPC key control plane entities - as a case study. In our work, the MME is deployed as a cluster of multiple virtual instances (vMMEs) and a front-end load balancer. We focus on investigating different approaches to achieve better load balancing among these vMMEs, which in turn improves scalability. Our experimental results suggest that carefully selected load balancing algorithms can significantly reduce the control plane latency.In mobile networks, the mobile core plays a crucial role in providing connectivity between mobile user devices and external packet data networks such as the Internet. After more than three decades, the mobile core has been gradually evolved through four generations and is called the Evolved Packet Core (EPC) in the current generation (4G). In recent years, the explosion of mobile data traffic and devices and the advent of new services have led to the investigation of the next generation of mobile networks, i.e., 5G. Among other technology candidates, Software Defined Networking (SDN) and Network Function Virtualization (NFV) have been widely considered to be key enablers for the network architecture of 5G, especially the mobile packet core (MPC) network. This thesis aims at identifying benefits and challenges of introducing SDN and NFV to re-achitect the current MPC architecture towards 5G and addressing some of the challenges. To this end, we conduct a comprehensive survey of the existing SDN/NFV-based MPC architectures. Through this survey work, several research questions for future work have been identified and we contribute to address two of the research questions. Firstly, we propose an SDN/NFV-based MPC architecture for providing multicast and broadcast services. Secondly, we tackle the scalability problem of the Mobility Management Entity (MME) - one of the EPC key control plane entities. In particular, we investigate different approaches to achieve better load balancing among virtual MMEs in a virtual and distributed MME design, which in turn improves scalability.
HITS, 4707
6
Aravinthan, Gopalasingham. "SDN based service oriented control approach for future radio access networks." Thesis, Evry, Institut national des télécommunications, 2017. http://www.theses.fr/2017TELE0013.
Повний текст джерелаАнотація:
Le SDN (Software-Defined Networking) émerge comme une nouvelle architecture pour la programmation des réseaux. A l'origine, l'idée du SDN est de déplacer le plan de contrôle à l'extérieur des équipements, et de permettre ainsi un contrôle déporté de l'ensemble depuis une entité logicielle logique nommée "contrôleur". Le principal avantage d'une telle approche est de centraliser donc toute l'intelligence de gestion du réseau dans le contrôleur, qui s'appuie pour cela sur des protocoles standard et assure par ce biais la reprogrammation de la totalité de la partie du réseau sous son contrôle. L'évolution technologique vers le SDN est toujours en cours dans des scénarios de déploiement programmable et flexible des réseaux mobiles. Le NFV (Network Function Virtualization) est le processus de déplacement ou de migration des fonctions réseau d'un équipement dédié de réseau vers des serveurs génériques dans le Cloud. Les SDN et NFV sont deux technologies étroitement liées qui sont souvent utilisées ensemble. Le couplage fort entre les plans de contrôle et de données, ainsi que les limitations en matière de passage à l'échelle et de flexibilité, font que la virtualisation des réseaux mobiles actuels nécessite non seulement l'utilisation du Cloud Computing mais aussi les récentes innovations telles que SDN et NFV pour pouvoir permettre un déploiement à la demande des services réseaux (Network-as-a-Service) aux utilisateurs. Les lignes de recherche globales de cette thèse s'inscrivent dans deux principaux cas d'utilisation. Ces cas d'utilisation, bien qu'appelés de la "prochaine génération de réseaux mobiles", sont le "Telco" et le "Vertical", qui apparaissent ici couplés, les deux étant traditionnellement complètement séparés. Dans les cas d'utilisation de "télécommunications", nous exploitons les avantages de SDN pour avoir un cadre de contrôle flexible pour les réseaux d'auto-organisation (SON) et la division de traitement dynamique des utilisateurs. Dans le cas d'utilisation de "verticale", nous appliquons divers avantages du protocole SDN et OpenFlow pour utiliser efficacement les ressources radio du réseau de backhaul dans le système de communication train-sol. Notre cadre d'étude du SDN, en général, peut être une solution efficace et alternative pour la gestion RAN (Radio Access Network), c'est-à-dire pour des objectives comme l'optimisation des ressources radio, l'optimisation du réseau, la gestion de la mobilité et l'équilibrage de la charge, peuvent être atteint avec ce cadre. Grâce à l'analyse et l'expérimentation concrète des SDN et NFV pour le RAN, nous montrons que les solutions proposées dans ce travail peuvent apporter un faisceau d'avantages évidents aux réseaux mobiles tels que la flexibilité, la programmabilité, la gestion unifiée et la mise en œuvre de nouveaux servicesSoftware-Defined Networking (SDN) has emerged as a new intelligent architecture for network programmability. The primary idea behind SDN is to move the control-plane outside the switches and enable external control of data-plane through a logical software entity called controller. Such approach benefits mobile network management by brining complete intelligence to the logically centralized controller. Network Function Virtualization (NFV) is the process of relocating or migrating network functions from dedicated hardware to generic servers. SDN and NFV are two closely related technologies that are often used together. The traditional mobile network architecture due to its strongest coupling between control and data planes along with limitations in scalability and flexibility requires the usage of cloud computing along with the recent revolutionary approaches in networking such as SDN and NFV to have an architecture that deploys on demand "Network-as-a-Service" for users. The global research focus of this thesis falls in to two main use cases of next generation mobile networks such as Telco and Vertical. In the telco use cases, we exploit the advantages of SDN to have flexible control framework for both Self-Organizing Networks (SON) and dynamic user processing split. In vertical use case, we apply various advantages of SDN and OpenFlow protocol to efficiently utilize the scare radio resources of wireless backhaul network in the train-to-ground communication system. Our SDN framework in general can be an efficient and alternative solution for RAN management i.e. Radio Optimization, Network Optimization, Mobility Management and Load Balancing can be achieved with such framework. Through analysis and experimentation of SDN frameworks for RAN, we shows that the proposed solutions can bring set of advantages to wireless networks such as flexibility, programmability, unified management, and enables new services
7
Кузнєцов, Ярослав Іванович. "Спосіб балансування навантаження в масштабних програмноконфігурованих мережах". Master's thesis, КПІ ім. Ігоря Сікорського, 2020. https://ela.kpi.ua/handle/123456789/34050.
Повний текст джерелаАнотація:
Робота складається із вступу, трьох розділів та одного додатку. Загальний
обсяг роботи: 69 аркуші основного тексту, 41 ілюстрація, 6 таблиць. При
підготовці використовувалася література з 38 різних джерел.
Актуальність. Дедалі більшу популярність набуває стрімінгові сервіси,
зростає кількість мережевих сервісів та абонентів мережі, що потребують
забезпечення якості обслуговування. Традиційні мережі наближаються до своєї
межі ефективності. Альтернативою традиційним мережам є централізована
архітектура SDN.
Ідея технології SDN не є новою, проте активне впровадження технології
припадає лише на останні 15 років. Однією із важливих задач при організації
мережі є задача балансування трафіку, що включає в собі маршрутизацію та
забезпечення якості обслуговування. Використання нової технології вимагає
розробки нових алгоритмів та протоколів, або адаптації традиційних, задача
балансування трафіку є актуальною.
Мета і завдання дослідження. Метою магістерської роботи є
розроблення методу, що дозволить маршрутизувати трафік по оптимальним
шляхам, уникаючи високої затримки та забезпечення більш рівномірного
завантаження мережі шляхом балансування трафіку, з використанням
можливостей програмно-конфігурованих мереж.
Для досягнення мети дослідження поставлено і вирішено такі завдання:
• дослідження структури та принципів побудови програмноконфігурованих мереж;
• дослідження методів масштабування програмно-конфігурованих
мереж;
• дослідження методів забезпечення якості обслуговування в
класичних та програмно-конфігурованих мережах;
• Дослідження методів маршрутизації в програмно-конфігурованих
мережах;
• Дослідження методів рішення задач багатокритеріальної
оптимізації;
• Pозробка методу балансування трафіку в програмно-конфігурованих мережах;
• Розробка програмного модулю на основі розробленого методу;
• Ілюстрація роботи моделі та аналіз отриманих результатів.
Об’єкт дослідження – процес пошуку оптимального шляху між вузлами
в програмно-конфігурованих мережах.
Предмет дослідження – методи маршрутизації та визначення оптимальності маршруту в програмно-конфігурованих мережах.
Методи досліджень. Для досягнення поставлених в магістерській роботі
задач, використано методи теорії графів, методи моделювання, методи
вирішення задач багатокритеріальної організації.
Проведене дослідження дає можливість використання розробленої моделі
в SDN мережах в якості застосунку контролера та виконувати емуляцію роботи
мережі для прогнозування трафіку та завантаженості компонентів мережі.
Особистий внесок здобувача. Магістерське дослідження є самостійно
виконаною роботою, в якій відображено особистий авторський підхід та
особисто отримані теоретичні та прикладні результати, що відносяться до
вирішення задачі маршрутизації та контролю трафіку в SDN мережах.
Формулювання мети та завдань дослідження проводилось спільно з науковим
керівником.
Практична цінність. Отримані результати можуть використовуватися у
майбутніх дослідженнях за напрямками:
• вдосконалення методів маршрутизації;
• аналіз та прогнозування трафіку в SDN;
• балансування навантаження в SDN мережах.Current work consists of receipt, three sections and one application. Total amount of work: 69 pages of the main text, 41 illustrations, 6 tables. By preparation a literature from 38 different sources was used. Topic Relevance. The increasing popularity acquires streaming services, the number of network services and subscribers of network grows that need ensuring quality of service. Traditional networks come nearer to the limit of efficiency. An alternative to traditional networks is the centralized architecture of SDN. The idea of SDN technology is not new, however active implementation of technology falls only on the last 15 years. The problem of balancing of traffic is one of important tasks at the organization of network that includes in itself routing and ensuring quality of service. Use of new technology demands development of new algorithms and protocols, or adaptation traditional, the problem of balancing of traffic is relevant. Research goal. The research goal of the master's thesis is development of a method that will allow to route traffic on optimal ways, avoiding a high delay and ensuring more uniform loading of network by balancing of traffic, with use of opportunities of software defined networks. For achievement of the goal of a research it is put and solved the following tasks: • Research of structure and the principles of construction software defined networks; • Researches of methods scaling software defined networks; • Researches of methods of ensuring quality of service in classical and software defined networks; • Researches of methods of routing in software defined networks; • Researches of methods of solving problems of multicriterial optimization; • Development of a method of balancing of traffic in software defined networks; • Development of the program module on the basis of the developed method; • Illustration of work of model and the analysis of the received results. Object of research – Process of search of an optimal way between nodes in software defined networks. Subject of research – Methods of routing and determination of optimality of a route in software defined networks. Methods of research. For achievement of the tasks set in the master's thesis, it is used methods of the theory of graphs, modeling methods, methods of the solution of tasks of the multicriteria organization. The conducted research gives the chance of use of the developed model in SDN networks as an application of the controller and to carry out emulation of network functioning for forecasting of traffic and load of components of network. Scientific contribution. The master research is independently done work in which it is reflected personal author's approach and personally received theoretical and applied results relating to the solution of a problem of routing and control of traffic in SDN networks. A formulation of the purpose and tasks the research was conducted together with the research supervisor. Practical value of obtained results. The received results can be used in future researches on the directions: • to improvement of methods of routing; • the analysis and forecasting of traffic in SDN; • balancing of loading in SDN networks.
8
Carpa, Radu. "Energy Efficient Traffic Engineering in Software Defined Networks." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEN065/document.
Повний текст джерелаАнотація:
Ce travail a pour but d'améliorer l'efficacité énergétique des réseaux de cœur en éteignant un sous-ensemble de liens par une approche SDN (Software Defined Network). Nous nous différencions des nombreux travaux de ce domaine par une réactivité accrue aux variations des conditions réseaux. Cela a été rendu possible grâce à une complexité calculatoire réduite et une attention particulière au surcoût induit par les échanges de données. Pour valider les solutions proposées, nous les avons testées sur une plateforme spécialement construite à cet effet.Dans la première partie de cette thèse, nous présentons l'architecture logicielle ``SegmenT Routing based Energy Efficient Traffic Engineering'' (STREETE). Le cœur de la solution repose sur un re-routage dynamique du trafic en fonction de la charge du réseau dans le but d'éteindre certains liens peu utilisés. Cette solution utilise des algorithmes de graphes dynamiques pour réduire la complexité calculatoire et atteindre des temps de calcul de l'ordre des millisecondes sur un réseau de 50 nœuds. Nos solutions ont aussi été validées sur une plateforme de test comprenant le contrôleur SDN ONOS et des commutateurs OpenFlow. Nous comparons nos algorithmes aux solutions optimales obtenues grâce à des techniques de programmation linéaires en nombres entiers et montrons que le nombre de liens allumés peut être efficacement réduit pour diminuer la consommation électrique tout en évitant de surcharger le réseau.Dans la deuxième partie de cette thèse, nous cherchons à améliorer la performance de STREETE dans le cas d’une forte charge, qui ne peut pas être écoulée par le réseau si des algorithmes de routages à plus courts chemins sont utilisés. Nous analysons des méthodes d'équilibrage de charge pour obtenir un placement presque optimal des flux dans le réseau.Dans la dernière partie, nous évaluons la combinaison des deux techniques proposées précédemment : STREETE avec équilibrage de charge. Ensuite, nous utilisons notre plateforme de test pour analyser l'impact de re-routages fréquents sur les flux TCP. Cela nous permet de donner des indications sur des améliorations à prendre en compte afin d'éviter des instabilités causées par des basculements incontrôlés des flux réseau entre des chemins alternatifs. Nous croyons à l'importance de fournir des résultats reproductibles à la communauté scientifique. Ainsi, une grande partie des résultats présentés dans cette thèse peuvent être facilement reproduits à l'aide des instructions et logiciels fournisThis work seeks to improve the energy efficiency of backbone networks by automatically managing the paths of network flows to reduce the over-provisioning. Compared to numerous works in this field, we stand out by focusing on low computational complexity and smooth deployment of the proposed solution in the context of Software Defined Networks (SDN). To ensure that we meet these requirements, we validate the proposed solutions on a network testbed built for this purpose. Moreover, we believe that it is indispensable for the research community in computer science to improve the reproducibility of experiments. Thus, one can reproduce most of the results presented in this thesis by following a couple of simple steps. In the first part of this thesis, we present a framework for putting links and line cards into sleep mode during off-peak periods and rapidly bringing them back on when more network capacity is needed. The solution, which we term ``SegmenT Routing based Energy Efficient Traffic Engineering'' (STREETE), was implemented using state-of-art dynamic graph algorithms. STREETE achieves execution times of tens of milliseconds on a 50-node network. The approach was also validated on a testbed using the ONOS SDN controller along with OpenFlow switches. We compared our algorithm against optimal solutions obtained via a Mixed Integer Linear Programming (MILP) model to demonstrate that it can effectively prevent network congestion, avoid turning-on unneeded links, and provide excellent energy-efficiency. The second part of this thesis studies solutions for maximizing the utilization of existing components to extend the STREETE framework to workloads that are not very well handled by its original form. This includes the high network loads that cannot be routed through the network without a fine-grained management of the flows. In this part, we diverge from the shortest path routing, which is traditionally used in computer networks, and perform a particular load balancing of the network flows. In the last part of this thesis, we combine STREETE with the proposed load balancing technique and evaluate the performance of this combination both regarding turned-off links and in its ability to keep the network out of congestion. After that, we use our network testbed to evaluate the impact of our solutions on the TCP flows and provide an intuition about the additional constraints that must be considered to avoid instabilities due to traffic oscillations between multiple paths
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Burrows, Richard B. P. "Dynamic load balancing." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363886.
Повний текст джерела
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Nagel, Lars. "Randomised load balancing." Thesis, Durham University, 2011. http://etheses.dur.ac.uk/3207/.
Повний текст джерелаАнотація:
Due to the increased use of parallel processing in networks and multi-core architectures, it is important to have load balancing strategies that are highly efficient and adaptable to specific requirements. Randomised protocols in particular are useful in situations in which it is costly to gather and update information about the load distribution (e.g. in networks). For the mathematical analysis randomised load balancing schemes are modelled by balls-into-bins games, where balls represent tasks and bins computers. If m balls are allocated to n bins and every ball chooses one bin at random, the gap between maximum and average load is known to grow with the number of balls m. Surprisingly, this is not the case in the multiple-choice process in which each ball chooses d > 1 bins and allocates itself to the least loaded. Berenbrink et al. proved that then the gap remains ln ln(n) / ln(d). This thesis analyses generalisations and variations of the multiple-choice process. For a scenario in which batches of balls are allocated in parallel, it is shown that the gap between maximum and average load is still independent of m. Furthermore, we look into a process in which only predetermined subsets of bins can be chosen by a ball. Assuming that the number and composition of the subsets can change with every ball, we examine under which circumstances the maximum load is one. Finally, we consider a generalisation of the basic process allowing the bins to have different capacities. Adapting the probabilities of the bins, it is shown how the load can be balanced over the bins according to their capacities.
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Clifton, Christopher W. "Dynamic load balancing." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/81504.
Повний текст джерелаАнотація:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaves 72-74.
by Christopher W. Clifton.
M.S.
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Friedetzky, Thomas. "Randomised dynamic load balancing." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=96937979X.
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Wang, Chunpu. "Distributed random load balancing." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/61801.
Повний текст джерелаАнотація:
Low latency is highly desirable for cloud services spanning thousands of servers. With the rapid development of cloud market, the size of server farms grows fast. Hence, stringent timing requirements are needed for task scheduling in a large-scale server farm. Conventionally, the Join-the-Shortest-Queue (JSQ) algorithm, which directs an arriving task to the least loaded server, is adopted in scheduling. Despite its excellent delay performance, JSQ is throughput-limited, and thus doesn't scale well with the number of servers. There are two distributed algorithms proposed as "approximations" of the idealized JSQ. The first one is the Power-of-d-choices (Pod) algorithm, which selects d servers at random and routes a task to the least loaded server of the d servers. Despite its scalability, Pod suffers from long tail response times. The second one is the distributed Join-the-Idle-Queue (JIQ), which take advantages idle servers for task scheduling.
In this thesis, we are interested in exploring Pod and JIQ further. First, a hybrid scheduling strategy called Pod-Helper is proposed. It consists of a Pod scheduler and a throughput-limited helper. Hybrid scheduling takes the best of both worlds, enjoying scalability and low tail response times. In particular, hybrid scheduling has bounded maximum queue size in the large-system regime, which is in sharp contrast to the Pod scheduling whose maximum queue size is unbounded. Second, we conduct an in-depth analysis for distributed Join-the-Idle-Queue (JIQ), a promising new approximation of an idealized task-scheduling algorithm. In particular, we derive semi-closed form expressions for the delay performance of distributed JIQ. Third, we propose a new variant of distributed JIQ that offers clear advantages over alternative algorithms for large systems.Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
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Khan, Muhammad. "A self-optimised cloud radio access network for emerging 5G architectures." Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/16050.
Повний текст джерелаАнотація:
Network densification has become a dominant theme for capacity enhancement in cellular networks. However, it increases the operational complexity and expenditure for mobile network operators. Consequently, the essential features of Self-Organising Networks (SON) are considered to ensure the economic viability of the emerging cellular networks. This thesis focuses on quantifying the benefits of self-organisation in Cloud Radio Access Network (C-RAN) by proposing a flexible, energy efficient, and capacity optimised system. The Base Band Unit (BBU) and Remote Radio Head (RRH) map is formulated as an optimisation problem. A self-optimised C-RAN (SOCRAN) is proposed which hosts Genetic Algorithm (GA) and Discrete-Particle-Swarm-Optimisation algorithm (DPSO), developed for optimisation. Computational results based on different network scenarios demonstrate that DPSO delivers excellent performances for the key performance indicators compared to GA. The percentage of blocked users is reduced from 10.523% to 0.409% in a medium sized network scenario and 5.394% to 0.56% in a vast network scenario. Furthermore, an efficient resource utilisation scheme is proposed based on the concept of Cell Differentiation and Integration (CDI). The two-stage CDI scheme semi-statically scales the number of BBUs and RRHs to serve an offered load and dynamically defines the optimum BBU-RRH mapping to avoid unbalanced network scenarios. Computational results demonstrate significant throughput improvement in a CDI-enabled C-RAN compared to a fixed C-RAN, i.e., an average throughput increase of 45.53% and an average blocked users decrease of 23.149% is experienced. A power model is proposed to estimate the overall power consumption of C-RAN. Approximately 16% power reduction is calculated in a CDI-enabled C-RAN when compared to a fixed C-RAN, both serving the same geographical area. Moreover, a Divide-and-Sort load balancing scheme is proposed and compared to the SOCRAN scheme. Results show excellent performances by the Divide-and-Sort algorithm in small networks when compared to SOCRAN and K-mean clustering algorithm.
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Mohammad, Malik Adeel, and Saeed Muhammad Sheharyar. "Load Balancing in Microwave Networks." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121698.
Повний текст джерелаАнотація:
Microwave links are very commonly used in carrier networks especially towards the access side. They not only ease deployment of a network but are also very cost effective. However, they bring along a multitude of challenges which are characteristic of the wireless technology. Microwave links are fickle. Being exposed to varying weather conditions, they experience bandwidth fluctuations. This is true especially in the case of links operating at higher frequencies. The unpredictable nature of microwave links makes it quite challenging to plan capacity in a network beforehand. Radio links employ adaptive modulation. They operate on a range on modulation schemes each of which offers different throughput and bit error rates. When operating at a low bit rate modulation scheme, a situation may arise where the microwave link is not able to support the entire traffic incident from the backbone network. As a result, the microwave link will suffer from congestion and packets arriving at the microwave link will eventually be dropped. The switching nodes that precede the microwave link along a communication path are unaware of the microwave link conditions and, therefore, continue to transmit traffic at a high rate. Large carrier networks cannot afford to have performance inconsistencies like data loss and increased latency. Service degradation, even for a very short duration, can have dire consequences in terms of customer dissatisfaction and revenue loss. The goal of this thesis is to use MPLS-TP Linear Protection to load balance traffic across alternative paths in a network where links use adaptive modulation. Rerouted traffic must take other paths so that the congested microwave link is completely avoided. The idea is augmented by the use of a radio condition signaling mechanism between the packet switching node and the microwave node that precede a microwave link. The microwave node sends radio condition control messages to the preceding packet switching node to rate limit traffic and avoid congestion at the microwave link. The result of this thesis work is a system prototype that achieves the stated goal. Evaluation of the prototype is carried out through graphical results, generated by a traffic generator, that advocate the correctness, performance and robustness of the system.
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Montag, David. "Load balancing of IP telephony." Thesis, Linköping University, Department of Computer and Information Science, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-16066.
Повний текст джерелаАнотація:
In today's world, more and more phone calls are made over IP. This results in an increasing demand for scalable IP telephony equipment.
Ingate Systems AB produces firewalls specialized in handling IP telephony. They have an inherent limit in the number of concurrent phone calls that they can handle. This can be a bottleneck at high loads. There is a load balancing solution available in the platform, but it has a number of drawbacks, such as media latency and client capability requirements, limiting its usage.
Many companies provide load balancing solutions for SIP. However, it appears few handle all the problematic scenarios that the Ingate firewall does. This master's thesis aims to add load balancing functionality to the Ingate firewall, so that it can handle all types of clients.
By splitting the firewall into two completely separate layers - a SIP layer and a firewall layer - the concept of a virtual machine emerges. A machine is no longer restricted to its physical SIP and firewall layers. Instead, virtual machines are used to process calls. They still have SIP and firewall layers, but the layers can reside on different physical machines.
This thesis demonstrates the operation of an innovative load balancing implementation. The implementation was evaluated, and using four machines the test setup performed 50% better than the original Ingate platform, while still retaining all functionality -- something that was not possible with the original platform. This surpassed both the company's and my own expectations.
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Macharia, Geoffrey Muragori. "Cellular load distribution : dynamic load balancing in scalable multicomputers." Thesis, University of York, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276343.
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Do, Manh Duc. "Green Cloud - Load Balancing, Load Consolidation using VM Migration." TopSCHOLAR®, 2017. https://digitalcommons.wku.edu/theses/2059.
Повний текст джерелаАнотація:
Recently, cloud computing is a new trend emerging in computer technology with a massive demand from the clients. To meet all requirements, a lot of cloud data centers have been constructed since 2008 when Amazon published their cloud service. The rapidly growing data center leads to the consumption of a tremendous amount of energy even cloud computing has better improved in the performance and energy consumption, but cloud data centers still absorb an immense amount of energy. To raise company’s income annually, the cloud providers start considering green cloud concepts which gives an idea about how to optimize CPU’s usage while guaranteeing the quality of service. Many cloud providers are paying more attention to both load balancing and load consolidation which are two significant components of a cloud data center.
Load balancing is taken into account as a vital part of managing income demand, improving the cloud system’s performance. Live virtual machine migration is a technique to perform the dynamic load balancing algorithm. To optimize the cloud data center, three issues are considered: First, how does the cloud cluster distribute the virtual machine (VM) requests from clients to all physical machine (PM) when each computer has a different capacity. Second, what is the solution to make CPU’s usage of all PMs to be nearly equal? Third, how to handle two extreme scenarios: rapidly rising CPU’s usage of a PM due to sudden massive workload requiring VM migration immediately and resources expansion to respond to substantial cloud cluster through VM requests. In this chapter, we provide an approach to work with those issues in the implementation and results. The results indicated that the performance of the cloud cluster was improved significantly.
Load consolidation is the reverse process of load balancing which aims to provide sufficient cloud servers to handle the client requests. Based on the advance of live VM migration, cloud data center can consolidate itself without interrupting the cloud service, and superfluous PMs are turned to save mode to reduce the energy consumption. This chapter provides a solution to approach load consolidation including implementation and simulation of cloud servers.
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Pham, Vinh. "Performing Gateway Load Balancing in MANETs." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for telematikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-15131.
Повний текст джерелаАнотація:
During the last decades, the advances in Information Technology have formed the basis for increased interest and research activity in the field of ad hoc wireless multihop networks or simply ad hoc networks. This emerging technology enables internetworking between wireless nodes that are deployed in an ad hoc and temporary manner. All nodes in an ad hoc network take the role as both hosts in an end-to-end communication session, or as routers to collaboratively relay data traffic in a multihop fashion on behalf of other nodes. Furthermore, ad hoc networks are highly dynamic in nature, i.e. nodes can join or leave the network at any time, and additionally, the nodes have also the flexibility to move around while being in the network. The fact that ad hoc networks can be rapidly deployed with minimal prior planning, cost, and without the need of any pre-existing infrastructure makes this technology very attractive and suitable in a number of applications, including emergency and rescue operations, and military operations. Although ad hoc networks represent a promising technology that offers a broad range of potential useful applications, this technology is still in an immature phase. There are yet many issues and challenges that need to be resolved, which mainly arise from the inherent unreliability of wireless communication, the dynamic nature of these networks, the limited availability in resources with respect to bandwidth, processing capacity, battery power, and from the possibly large scale of these networks. These challenges require that the networking protocols at all layers in the network stack, that in many cases were originally designed for wired networks, must be modified or optimized, in order to adapt to the characteristic of the wireless environment. The focus of this thesis has been devoted to the investigation of two specific issues within the field of ad hoc networking, i.e. node mobility and load balancing. The aim is to provide solutions in order to improve the overall performance in ad hoc networks. Node mobility is one of the most important features in ad hoc networks, however, it is also the reason for frequent link breaks and the constant change in the topology. An ongoing data transmission that is interrupted by a link break, must be rerouted to alternative paths in order to circumvent the broken link. However, this process of rerouting traffic takes a certain amount of time, which is referred to as the rerouting time. Minimizing the rerouting time is essential in order to reduce packet loss and improve network performance. In this thesis we investigate the factors that affect the rerouting time in proactive routing protocols and propose solutions for minimizing it. Load balancing refers to the process of distributing traffic load more evenly in the network in order to minimize congestion and to optimize the usage of network resources. Performing load balancing in ad hoc networks is generally very challenging due to the inherently interfering nature of the wireless medium. In this thesis we therefore investigate the feasibility and the potential benefits of performing load balancing in ad hoc networks. We consider two scenarios, i.e. load balancing for intradomain and interdomain traffic. Intradomain traffic is traffic between nodes inside an ad hoc network. Performing load balancing on intradomain traffic can be done in two ways. The first is referred to as multipath load balancing where a traffic flow between a source and destination pair is distributed over multiple alternative disjoint/semi-disjoint paths. The aim is to maximize throughput and reduce the risk for packet loss. However, a number of previous work has investigated and reported that this type of load balancing can only provide a rather limited improvement in performance due to the interference between the paths [1] [2]. Due to this reason, multipath load balancing is therefore not considered in this thesis. Instead we focus on the second way which is referred to as transit routing. Transit routing is about routing part of the local traffic over a backbone network in order to relief the traffic load in the ad hoc network. The assumption behind this concept is a network architecture similar to a Wireless Mesh Network (WMN), where a high capacity backbone network is an integrated part of the Mobile Ad hoc Network (MANET). This backbone network is commonly used to provide Internet-connectivity services, but can also be exploited to alleviate the traffic load in the MANET. In addition, for certain source and destination pairs, performing transit routing can considerably increase the throughput compared to if the traffic is routed within the ad hoc network. Interdomain traffic refers to traffic between a node inside the ad hoc network and a remote node outside of the ad hoc network. Load balancing for interdomain traffic considers the potential of distributing interdomain traffic among multiple gateways in order to avoid congestion at the gateways and maximize the capacity for interdomain traffic. This type of load balancing is commonly referred to as gateway load balancing in the literature. Furthermore, interdomain can either be inbound or outbound traffic. The work in this thesis mainly focuses on performing load balancing for outbound traffic. However, we believe that the results in our work are also applicable to inbound traffic as well. The main contributions in this thesis are the investigation and the proposals of different solutions for intradomain and interdomain load balancing.
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Glazer, D. W. (David William). "Load balancing parallel discrete event simulations." Thesis, McGill University, 1992. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=39384.
Повний текст джерелаАнотація:
This thesis presents several load balancing algorithms for parallel discrete event simulations executed under both optimistic and conservative mechanisms. The algorithms rest upon recent developments in active process migration, which permits the use of dynamic strategies. Dynamic load balancing allow for re-adjustments when resource requirements vary during simulation. It is also useful when initial resource predictions are unknown or incorrect.A simulated multi-processor environment (PARALLEX) was developed in order to evaluate the algorithms. Results indicate that substantial performance gains may be realized with these algorithms.
This thesis also presents a scheme which allows the Time of Next Event algorithm (GROS89) to be employed as a complete deadlock prevention mechanism in shared memory environments. Comparisons are made to Chandy & Misra null message schemes.
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Garcia, Gasulla Marta. "Dynamic load balancing for hybrid applications." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/406040.
Повний текст джерелаАнотація:
It is well known that load imbalance is a major source of efficiency loss in HPC (High Performance Computing) environments. The load imbalance problem has very different sources, from static ones related to the data distribution to very dynamic ones, for example, the noise of the system.
In this thesis, we present DLB: Dynamic Load Balancing library. DLB is a framework to improve the efficient use of the computational resources of a computational node. With DLB we offer a dynamic solution to load imbalance problems. DLB is applied at runtime and does not need previous information to solve load imbalance problems, for this reason, it can deal with load imbalances coming from any source.
The DLB framework includes a novel load balancing algorithm: LeWI (Lend When Idle). The main idea of LeWI is to use the computational resources assigned to a process or thread when it is idle, to speed up another process running on the same node that it is still doing computation. We will see how this idea although being quite simple it is powerful and flexible to obtain an efficient use of resources close to the ideal one.En aquesta tesi presentem DLB (Dynamic Load Balancing), una llibreria que ajuda a fer un us eficient dels recursos d'un node de càlcul. Dins de DLB hem implementat un algoritme de balanceig original: LeWI (Lend When Idle). LeWI està basat en la idea que quan un procés MPI està esperant en una crida MPI bloquejant els recursos de càlcul que té assignats no estan ocupats. Per tant, aquests recursos els poden fer servir altres processos que s'estiguin executant al mateix node per acabar el seu càlcul més ràpid. DLB intercepta les crides MPI i canvia el nombre de threads OpenMP com calgui. Quan un procés arriba a una crida MPI bloquejant cedirà les seves CPUs a un altre procés que s'estigui executant al mateix node. Quan el primer procés MPI acabi la crida MPI bloquejant recuperarà les seves CPUs. Hem implementat LeWI a DLB i avaluat el seu rendiment, amb aquesta avaluació hem vist que DLB i LeWI poden millorar el rendiment d'aplicacions híbrides. LeWI pot balancejar aplicacions amb patrons regulars o irregular de desbalanceig sense modificar l'aplicació. Hem observat que la mal·leabilitat del model de programació i de l'aplicació pot afectar el rendiment que s'obté amb l'algoritme de balanceig. Tot i que OpenMP és mal·leable té una limitació, el nombre de threads només es pot canviar fora d'una regió paral·lela. El model de programació OmpSs és més mal·leable, ja que el nombre de threads es pot canviar en qualsevol punt. L'avaluació ens va demostrar que la mal·leabilitat del model de programació que es fa servir te un impacte substancial en el rendiment que obté l'algoritme de balanceig. Per defecte els diferents processos MPI es distribueixen de manera consecutiva entre els nodes de càlcul, però hem observat que en les aplicacions científiques la tendència és que els processos més carregats siguin consecutius. Per aquest motiu fer una distribució cíclica (Round Robin) dels processos MPI entre els nodes permet a l'algoritme de balanceig obtenir un millor rendiment. També hem observat que lligar els threads a CPUs o no fer-ho afecta al rendiment de les aplicacions i en especial quan es fa servir l'algoritme de balanceig. Per a permetre que LeWI pugui gestionar CPUs concretes hem modificat la llibreria perquè utilitzi mascares de CPUs. Amb l'avaluació hem vist que lligar els threads a CPUs té un impacte important en el rendiment que s'obté. Però també que l'impacte depèn de la mida del node (nombre de CPUs per node) i l'estructura de la memòria. Hem integrat DLB amb un runtime parallel, Nanos++. Aquesta integració ens ha mostrat el potencial d'aquest tipus de col·laboracions entre runtimes. Ens ha permès identificar els punts clau de coordinació necessaris i ens ha demostrat que DLB està preparat per a ser integrat amb altres runtimes paralels. L'avaluació ha mostrat el potencial d'aquest tipus d'integracions i col·laboracions. Finalment, hem fet una avaluació exhaustiva de l'entorn i l'algoritme amb una aplicació en producció: Alya. Hem vist que podem reduir fins a un 40% el temps d'execució per a situacions amb un alt desbalanceig. I en el cas de situacions sense desbalanceig l'ús de DLB no penalitza el rendiment de l'aplicació. També hem vist que el rendiment de la paral·lelització OpenMP de l'aplicació té un alt impacte en el rendiment de DLB i LeWI. Hem pogut provar que DLB i LeWI estan llestos per a ser utilitzats en execucions reals. I en executar proves d'escalabilitat fins a 16.000 cores hem vist que no només LeWI pot escalar fins a milers de cores sinó que l'algoritme de balanceig que només s'aplica dins del node de càlcul pot millorar el rendiment d'execucions en milers de nodes de càlcul.
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Liang, Zhengang. "Transparent Web caching with load balancing." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ59383.pdf.
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Nuttall, Mark Patrick. "Cluster load balancing using process migration." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267613.
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Maselino, Prince. "Load balancing for parallel 3D visualisation." Thesis, University of Westminster, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442101.
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Cronk, David. "Dynamic load balancing via thread migration." W&M ScholarWorks, 1999. https://scholarworks.wm.edu/etd/1539623961.
Повний текст джерелаАнотація:
Light-weight threads are becoming increasingly useful for parallel processing. This is particularly true for threads running in a distributed memory environment. Light-weight threads can be used to support latency hiding techniques, communication and computation overlap, and functional parallelism. Additionally, dynamic migration of light-weight threads supports both data locality and load balancing. Designing a thread migration mechanism presents some very unique and interesting challenges. One such challenge is maintaining communication between mobile threads. A potentially more difficult challenge involves maintaining the correctness of pointers within mobile threads. Since traditional pointers have no concept of address space, moving threads from processor to processor has a strong impact on the use of pointers. Options for dealing with pointers include restricting their use, adding a layer of software to support pointers referencing non-local data, and binding data to threads such that referenced data is always local to the thread. This dissertation presents the design and implementation of Chant, an efficient light-weight threads package which runs in a distributed memory environment. Chant was designed and implemented as a runtime system using MPI like and Pthreads like calls. Chant supports point-to-point message passing between threads executing in distributed address spaces. We focus on the use of Chant as a framework to support dynamic load balancing based on thread migration. We explore many of the issues which arise when designing and implementing a thread migration mechanism, as well as the issues which arise when considering the use of thread migration as a means for performing dynamic load balancing. This load balancing framework uses both system state information, including communication history, and user input. One of the basic functionalities of this load balancing framework is the ability of the user to customize the load balancing to fit particular classes of problems. This dissertation provides implementation details as well as discussion and justification of design choices. We go on to show that the overhead associated with our approach is within an acceptable range, and that significant performance gains can be achieved through the use of thread migration as a means of performing dynamic load balancing.
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Predari, Maria. "Load balancing for parallel coupled simulations." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0369/document.
Повний текст джерелаАнотація:
Dans le contexte du calcul scientique, l'équilibrage de la charge est un problème crucial qui conditionne la performance des simulations numériques parallèles. L'objectif est de répartir la charge de travail entre un nombre de processeurs donné, afin de minimiser le temps global d'exécution. Une stratégie populaire pour résoudre ce problème consiste à modéliser la simulation à l'aide d'un graphe et à appliquer des algorithmes de partitionnement. En outre, les simulations numériques tendent à se complexifier, notamment en mixant plusieurs codes représentant des physiques différentes ou des échelles différentes. On parle alors de couplage de codes multi-physiques ou multi-échelles. Dans ce contexte, le problème de l'équilibrage de charge devient également plus difficile, car il ne s'agit plus d'équilibrer chacun des codes séparément, mais l'ensemble de ces codes pris dans leur globalité. Dans ce travail, on propose de resoudre ce problème en utilisant le modèle de partitionnement à sommets fixes qui pourrait représenter efficacement les contraintes supplémentaires imposées par les codes couplés (co-partitionnement). Nous avons donc développé un algorithme direct de partitionnement de graphe qui gère des sommets fixes. L'algorithme a été implémenté dans le partitionneur Scotch et une série d'expériences ont été menées sur la collection des graphes DIMACS. Ensuite nous avons proposé trois algorithmes de co-partitionnement qui respectent les contraintes issues des codes couplés respectifs. Nous avons egalement validé nos algorithmes par une étude expérimentale en comparant nos méthodes aux strategies actuelles sur des cas artificiels ainsi que sur des codes réels couplésLoad balancing is an important step conditioning the performance of parallel applications. The goal is to distribute roughly equal amounts of computational load across a number of processors, while minimising interprocessor communication. A common approach to model the problem is based on graph structures and graph partitioning algorithms. Moreover, new challenges involve the simulation of more complex physical phenomena, where different parts of the computational domain exhibit different physical behavior. Such simulations follow the paradigm of multi-physics or multi-scale modeling approaches. Combining such different models in massively parallel computations is still a challenge to reach high performance. Additionally, traditional load balancing algorithms are often inadequate, and more sophisticated solutions should be explored. In this thesis, we propose new graph partitioning algorithms that balance the load of such simulations, refered to as co-partitioning. We formulate this problem with the use of graph partitioning with initially fixed vertices which we believe represents efficiently the additional constraints of coupled simulations. We have therefore developed a direct algorithm for graph partitioning that manages successfully problems with fixed vertices. The algorithm is implemented inside Scotch partitioner and a series of experiments were carried out on the DIMACS graph collection. Moreover we proposed three copartitioning algorithms that respect the constraints of the respective coupled codes. We finally validated our algorithms by an experimental study comparing our methods with current strategies on artificial cases and on real-life coupled simulations
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Ronoh, Kennedy, and Awoke Mengistie. "Load Balancing in Heterogeneous LTE-A Networks." Thesis, Linköpings universitet, Kommunikations- och transportsystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-81208.
Повний текст джерелаАнотація:
LTE-A is the latest cellular network technology. One feature of LTE-A is the use ofheterogeneous networks (HetNets) which consist of macro-cells and low power nodes(LPNs). One of the objectives of heterogeneous networks is to increase capacity especially inhotspot areas where there is high density of users. Due to their low transmit power, very fewusers associate with LPNs and this will result in load imbalance between LPNs and macrocells.Load balancing is therefore key issue in HetNets so as to maximize cell splitting gainsand ensure even user experiences. Cell range extension (CRE) is a technique that can be usedto achieve load balancing in HetNets. Under CRE, an offset is added to LPNs during cellselection so as to expand the range of LPNs and offload more users from macro-cells toLPNs. CRE usually involves the use of uniform offsets. The use of uniform offsets results insome degree of load balancing in a HetNet which is not optimal. This arises because differentLPNs require different offsets due to varying conditions such as user distribution andpropagation environment in different hotspots. The use of cell-specific offsets is necessary forimproving the level of load balancing in HetNets. In this thesis a heuristic load balancingalgorithm that is used to assign cell-specific offsets to LPNs is designed. The algorithm makesuse of a range optimization framework which applies the concept of cell load coupling. Ourresults show that the use of the cell-specific offsets results in not only a high degree of loadbalancing as measured by Jain’s fairness index but also more even user experiences in termsof throughput.
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El-Khatib, Khalil M. "Dynamic load balancing for clustered time warp." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=27311.
Повний текст джерелаАнотація:
In this thesis, we consider the problem of dynamic load balancing for parallel discrete event simulation. We focus on the optimistic synchronization protocol, Time Warp.A distributed load balancing algorithm was developed, which makes use of the active process migration in Clustered Time Warp. Clustered Time Warp is a hybrid synchronization protocol; it uses an optimistic approach between the clusters and a sequential approach within the clusters. As opposed to the centralized algorithm developed by H. Avril for Clustered Time Warp, the presented load balancing algorithm is a distributed token-passing one.
We present two metrics for measuring the load: processor utilization and processor advance simulation rate. Different models were simulated and tested: VLSI models and queuing network models (pipeline and distributed networks). Results show that improving the performance of the system depends a great deal on the nature of the simulated model.
For the VLSI model, we also examined the effect of the dynamic load balancing algorithm on the total number of processed messages per unit time. Performance results show that dynamically balancing the load, the throughput of the simulation was improved by more than 100%.
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Elsässer, Robert. "Spectral methods for efficient load balancing strategies." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965647145.
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El-Khatib, Khalil M. "Dynamic load balancing for clustered time warp." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0003/MQ29686.pdf.
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Skagos, P. Takis. "Load balancing in a heterogeneous, distributed environment." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq39153.pdf.
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Chow, Ka-po, and 周嘉寶. "Load-balancing in distributed multi-agent computing." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B3122426X.
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張立新 and Lap-sun Cheung. "Load balancing in distributed object computing systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31224179.
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Muniz, Francisco Junqueira. "Parallel load-balancing on message passing architectures." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239888.
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Chow, Ka-po. "Load-balancing in distributed multi-agent computing /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk:8888/cgi-bin/hkuto%5Ftoc%5Fpdf?B2295644x.
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Cheung, Lap-sun. "Load balancing in distributed object computing systems." Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2329428.
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Kumar, Rahul. "Load Balancing Parallel Explicit State Model Checking." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd455.pdf.
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Wallace, Brian T. "Automated system for load-balancing EBGP peers." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0008800.
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39
Adams, Daniel Alan. "Optimal Load Balancing in a Beowulf Cluster." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-050205-135758/.
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Iyer, Sundar. "Load balancing and parallelism for the internet /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Fellheimer, Eric Todd. "Dynamic load-balancing of StreamIt cluster computations." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36763.
Повний текст джерелаАнотація:
Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 145-147).
This thesis discusses the design and implementation of a dynamic load-balancing mechanism for computationally distributed programs running on a cluster written in the StreamIt programming language. StreamIt is useful for streaming data applications such as MPEG codecs. The structure of the language carries a lot of static information, such as data rates and computational hierarchy, and therefore lends itself well to parallelization. This work details a simulator for StreamIt cluster computations used to measure metrics such as throughput. Built on top of this simulation is an agent-based market used for load balancing the computation at StreamIt check-points to adapt to exogenously changing loads on the nodes of the cluster. The market models the structure of the computation as a supply chain. Our experiments study the throughput produced by the market compared to other policies, as well as qualitative features such as stability.
by Eric Todd Fellheimer.
M.Eng.
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Mäkeläinen, M. (Marko). "Algorithms for opportunistic load balancing cognitive engine." Master's thesis, University of Oulu, 2013. http://urn.fi/URN:NBN:fi:oulu-201303011071.
Повний текст джерелаАнотація:
Due to the increasing use of more and more powerful smart devices demands on the scarce radio spectrum are becoming more intense. One way to cope with increasing demands on radio spectrum is to apply innovative and flexible authorization schemes like spectrum sharing. Under the spectrum sharing paradigm, multiple users and/or systems are authorized to utilize the same spectrum band in a defined sharing agreement. A technology that is generally recommended for the implementation of spectrum sharing is called cognitive radio (CR). In this thesis, we design and implement a cognitive engine (CE) that intelligently and dynamically allocates spectrum resources to users. We first consider a scenario where a network has an exclusive access to a spectrum band and the CE accepts or rejects the arrival user requests based on an algorithm that takes into account a user’s priority and its bandwidth demand. We then consider a spectrum sharing scenario where along with the exclusive utilization to its own spectrum band a network also can opportunistically utilize another network’s spectrum band. For this scenario, we design and implement a CE that performs two main tasks: 1) Accepts or rejects arrival user requests based on a priority based algorithm; and 2) it intelligently load balances the user traffic between the two available network resources, while taking into account the primary user activity in the shared spectrum band. We provide a load balancing algorithm and evaluate its performance under different primary and secondary user traffic scenarios. We show that the proposed load balancing algorithm increases average throughput of the network and it also reduces the average number of users rejected by the networkYhä tehokkaampien älykkäiden langattomien päätelaitteiden nopea lisääntyminen johtaa niukan radiospektrin yhä kiihtyvään käyttöön. Eräs menetelmä radiospektrin lisääntyvän kysynnän tyydyttämiseen on hyödyntää innovatiivista ja joustavaa resurssin käytönjakoa kuten spektrin jakamista. Spektrinjakamismalli mahdollistaa useiden käyttäjien ja/tai järjestelmien yhtäaikaisen käytön samalla taajuuskaistalla hyödyntämällä sovittua käytäntöä resurssien jakamisesta. Radiospektrin jakaminen on tänä päivänä yleisesti suositeltu toteuttamaan hyödyntämällä kognitiivista radioteknologiaa. Tässä työssä suunnittellaan ja toteutetaan kognitiivinen päätöksentekokone, joka jakaa radiospektriresursseja käyttäjille älykkäästi ja dynaamisesti. Kognitiivista päätöksentekokonetta radioresurssien jakamisessa hyödynnetään kahdessa skenaariossa. Ensimmäisessä skenaariossa radioverkolla on yksinomainen pääsy taajuuskaistalle, jonka käyttöä kognitiivinen päätöksentekokone säätelee joko hyväksymällä tai hylkäämällä verkkoon liittyviä käyttäjiä. Kognitiivinen päätöksentekokoneen päätökset perustuu algoritmiin, joka ottaa huomioon käyttäjien määritetyn tärkeyden ja käyttäjän vaatiman kaistanleveyden. Seuraavassa skenaariossa radioverkko voi oman yksinomaisen taajuuskaistan lisäksi hyödyntää opportunisesti toisen radioverkon taajuuskaistaa silloin, kun siellä ei ole liikennettä. Tätä skenaariota varten suunnitteltiin kognitiivinen päätöksentekokone, jolla on kaksi päätehtävää: 1) hyväksyä tai hylätä verkkoon liittyviä käyttäjiä edellämainitun tärkeysperusteisen algoritmin avulla; ja 2) jakaa käyttäjien liikennettä kahden tarjolla olevan verkon välillä samalla ottaen huomioon opportunistisen resurssin pääkäyttäjien liikenteen jaetulla taajuuskaistalla. Tässä työssä esitellään toteutettu kuormantasausalgoritmi, jonka suorituskykyä tarkastellaan erilaisissa pääkäyttäjien ja toissijaisien käyttäjien liikenneskenaarioissa. Simulaatiotulokset osoittavat, että esitellyn kuormanjakoalgoritmin hyödyntäminen kognitiivisessa päätöksentekokoneessa parantaa verkon keskimääräistä siirtonopeutta, sekä vähentää keskimääräistä käyttäjien hylkäysastetta verkossa. Algoritmimme parantaa opportunistisen taajuuskaistan käyttöastetta. Algoritmimme ottaa myös huomioon käyttäjille asetetut prioriteetit ja parantaa korkeampi prioriteettisten käyttäjien asemaa verkossa. Tämä tulee ilmi muun muassa korkeampi prioriteettisten käyttäjien pienemmässä hylkäysasteessa
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Piccinini, Federico. "Dynamic load balancing based on latency prediction." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-143333.
Повний текст джерелаАнотація:
Spotify is a music streaming service that offers access to a vast music catalogue; it counts more than 24 million active users in 28 different countries. Spotify's backend is made up by a constellation of independent loosely-coupled services; each service consists of a set of replicas, running on a set of servers in multiple data centers: each request to a service needs to be routed to an appropriate replica. Balancing the load across replicas is crucial to exploit available resources in the best possible way, and to provide optimal performances to clients. The main aim of this project is exploring the possibility of developing a load balancing algorithm that exploits request-reply latencies as its only load index. There are two reasons why latency is an appealing load index: in the first place it has a significant impact on the experience of Spotify users; in the second place, identifying a good load index in a distributed system presents significant challenges due to phenomena that might arise from the interaction of the different system components such as multi-bottlenecks. The use of latency as load index is even more attractive under this light, because it allows for a simple black box model where it is not necessary to model resource usage patterns and bottlenecks of every single service individually: modeling each system would be an impractical task, due both to the number of services and to the speed at which these services evolve. In this work, we justify the choice of request-reply latency as a load indicator, by presenting empirical evidence that it correlates well with known reliable load index obtained through a white box approach. In order to assess the correlation between latency and a known load index obtained through a white box approach, we present measurements from the production environment and from an ad-hoc test environment. We present the design of a novel load balancing algorithm based on a modified ' accrual failure detector that exploits request-reply latency as an indirect measure of the load on individual backends; we analyze the algorithm in detail, providing an overview of potential pitfalls and caveats; we also provide an empirical evaluation of our algorithm, compare its performances to a pure round-robin scheduling discipline and discuss which parameters can be tuned and how they affect the overall behavior of the load balancer.
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Lin, Te-Sun, and 林德森. "Energy-Aware Load Balancing for Distributed SDN Controllers." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/75809248381322274600.
Повний текст джерелаАнотація:
碩士國立交通大學
網路工程研究所
103
Unlike the traditional network, the Software Defined Network (SDN) provides a way to control flows in a network by decoupling the control plane and data plane. Since an SDN network using a single controller to manage flows in the network may lead to SDN scalability and a single point of failure problems, some related work puts an emphasis on the issues of distributed SDN controllers. A related work on distributed SDN controllers or multiple SDN controllers, EstiCon, proposed a dynamic load balancing scheme. However, the issue of energy saving for distributed SDN controllers hasn’t been addressed. The main contributions of this paper are as follows. (1) We propose an Energy-Aware Load Balancing (EALB) algorithm for distributed SDN controllers. The proposed EALB balances the loads of distributed SDN controllers and turns some controllers into sleep mode under light load. The loads of SDN controllers are mainly caused by number of packet-in messages received. When packet-in messages become too many for a controller to handle, its loading needs to be migrated. When a controller becomes overloaded, the proposed EALB migrates some switches handled by the overloaded controller to other controllers in order to balance the loads. (2) In addition, we use a neural network based predictor to check whether it can turn a controller into sleep mode for energy saving. Simulation results show that the proposed EALB can save 11% of energy consumption compared to LB (EALB without energy saving). For load balancing of distributed SDN controllers, the load balancing metric (LBM) of the proposed EALB is from 1.19 to 1.4 under packet-in message rates from 300 to 900 (messages/second), which is only slightly higher than that (from 1.16 to 1.35) of LB. Keywords: Energy-aware, load balancing, neural network-based prediction, packet-in message, software defined network. Keywords: Energy-aware, Load balancing, neural network-based prediction, packet-in message, software defined network.
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Lin, Yung-Tang, and 林詠棠. "Study of Load Balancing Routing scheme in SDN." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/2u4z35.
Повний текст джерелаАнотація:
碩士國立中央大學
通訊工程學系在職專班
106
Today, Network is an indispensable part of humanity. You can acquire the information that you need with the use of it, as technology develops and humans make a great effort for exploring the future. With that large amounts of information which are inevitably available whether it's public or private information. To help increase the performance of the network in the current network architecture, as it has always been the focus of research in recent years. A Software-defined network (SDN) impact the traditional network architecture. Which has the features of： (1)Programmable (2)Separation of control plane and data plane (3)Centralized control Using SDN can achieve an improved network architecture than before. Load balancing needs to be used with routing algorithm. Its purpose is to ease the relative congestion in the network to accommodate new flow of relatively small load of path. It can improve overall network performance based on software-defined network (SDN) in this study, through the Open Flow protocol. It can be observed in the network system. For example: path or switch load conditions. It can be measure through the used amount of bandwidth on the path and the number of Flow Entry in the switches and to add Hop by considering threshold. Through the weight value that will improve the algorithm to calculate the best path.
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Lee, Yi-Jui, and 李易叡. "Load Balancing on SDN-Based Service Chaining using Openstack." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/6fxb9f.
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Chen, Yan-Ting, and 陳彥廷. "Genetic Algorithm based Load Balancing for SDN Multiple Controllers." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/t5k7v5.
Повний текст джерелаАнотація:
碩士國立交通大學
資訊科學與工程研究所
105
The software-defined network (SDN), which targets the improvement of network flexibility, is now putting efforts on deploying the multi-controller architecture for scalability. One major issue of the multi-controller architecture is that loads may be not evenly distributed among multiple controllers, thereby resulting in long response time of data traffic. Though there exist several load balancing mechanisms designed for the multi-controller architecture, they have two drawbacks. First, all of them seek to rely on a heuristic that the switch which generates the heaviest load is always assigned to the available controller with the lightest load. However, this heuristic may not lead to the optimal or near-optimal solution. Second, they did not consider switch migration cost, which determines the time consumption of load balancing. To address these two issues, we propose a Genetic Algorithm based Load Balancing (GALB) mechanism for the load balancing of the multi-controller architecture. In the GALB architecture, we deploy one global controller to mediate among multiple local controllers, which serve the switches’ requests. We then develop the GALB application at the global controller. GALB periodically monitors the local controllers’ loads, and triggers load balancing once their load deviation exceeds a specified threshold. The load balancing approach relies on the change of the switch-controller mapping to balance controllers’ loads. Moreover, more standby controllers are activated or some active controllers are put to sleep, when the overall loads are too heavy or too light. Experiment results show that GALB achieves better load balancing with the load balance metric (LBM) of 1.02, compared with the best LBM of the related works, 1.06. It also has better response time, 11.8 ms, and better load balancing time, 88.6 ms, compared with the best results of the related works, 12.14 ms and 118.01 ms, respectively.
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Lee, Yi-Ching, and 李宜璟. "SDN-based Mitigation of DoS Attacks for Load Balancing Service." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/du2j49.
Повний текст джерелаАнотація:
碩士國立中央大學
資訊工程學系
102
With the technology growth, user requirements for network services are becoming more and more diverse. Software-Defined Networking (SDN), an open network architecture, decouples the control functions from traditional network devices and uses OpenFlow as the communication protocol between control plane and forwarding plane. It also centralizes the network control to decrease the complexity of network topology. However, security issues remain in this emerging network architecture. These problems will cause SDN services interrupted and even collapsed when subjected to malicious DoS attacks. Therefore, this paper will provide a load balancing service with the proposed DoS attack mitigation mechanism in SDN network. This mitigated can increase the availability of SDN network, and ensure the service is normal when under attack. This thesis contains Active and Passive Mitigation mechanism for SDN network protection. In addition, two types of load balancing, TCP and UDP, are also included. TCP load balancing provides SYN Flooding Attack detection to lower hardware resource consumption. UDP load balancing uses reverse netmask method to reduce Control and Data Plane Interface (CDPI) loading. The experimental results show the proposed Active Mitigation can reduce 60.2% consumption of OpenFlow Switch computing power, SYN Flooding attack detection can reduce 95.77% consumption when TCP SYN Flooding occurs, and Passive mitigation by One-class Support Vector Machine can detect 98.8% abnormal traffic. All of these show the proposed mechanisms can effectively prevent SDN network service interruptions from DoS attacks.
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Sim, Wei-Chen, and 沈威辰. "SDN-Based Load Balancing System for High-Speed Rail Environment." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/x2sx6x.
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CHENG, HUI-SHENG, and 鄭暉盛. "Research on SDN-based Server Clusters with Dynamic Load Balancing." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/75yg23.
Повний текст джерелаАнотація:
碩士國立暨南國際大學
資訊管理學系
106
With the growth of cloud computing, lots of enterprises adopt cloud platforms to provide web services. The large-scale network management becomes a critical issue because providers of cloud platforms need to handle a great diversity of requirements in a complex network environment. Therefore, software defined networking (SDN) was proposed. SDN separates the control plane from a switch, and the control plane is centralized and programmable. It is more flexible and convenient for IT managers to manage a complicated and large-scale network. In this study, we develop a server cluster based on OpenFlow that is the most popular protocol in SDN field. We focus on the server-side load balancing issue and improve the performance of the OpenFlow-based server cluster. The OpenFlow controller we use is Floodlight that is open-source and has a built-in load balancer module. Its default load balancing policy is round-robin which is not appropriate for operating in a heterogeneous hardware environment and causes load imbalance. For this concern, we have modified the Floodlight’s load balancer module and proposed a load balancing policy: dynamic weighted random selection (DWRS). DWRS dynamically determines the weight of each server by collecting each server’s real-time loading, and dispatches requests according to the weight of each server. Therefore, the hardware resources can be utilized more effectively especially in a heterogeneous hardware environment. However, the way of executing load balancing algorithm in the original load balancer module is on-demand, meaning Floodlight executes the load balancing algorithm at once when it receives a packet-in message. It is not effective especially when mass packet-in messages arrive. Hence, we utilize multi-threaded technique in our design and devise a dedicated thread to pre-select the target server. This design enables Floodlight to directly designate the target server instead of executing the load-balancing algorithm at once while a packet-in message arrives. We have implemented various load-balancing policies in Floodlight’s load balancer module, including the proposed DWRS, least loading, least connections, and random selection. We then compare their performance with the default round-robin policy in Floodlight. During the performance evaluation, we design homogenous and heterogeneous hardware environments to evaluate the performance of all load balancing algorithms. The experimental results show the DWRS with multi-threaded implementation outperforms the default round-robin policy by 12%.