In the 21th century, we see a trend in which CPU processing power is not evolving at the same pace as it did in the century before. Also, in the current generation, the data requirements and the need for higher speed are increasing every day. This increasing demand requires multiple middlebox instances in order to scale. With recent progress in virtualization, middleboxes are getting virtualized and deployed as software (Network Function (NF)s) behind commodity CPUs. Various systems perform Load Balancing (LB) functionality in software, which consumes extra CPU at the NF side. There are research work in the past which tried to move the LB functionality from software to hardware. Majority of hardware­based load balancer only provides basic LB functionality and depends on NF to provide the current performance statistics. Providing statistics feedback to LB consumes processing power at the NF and creates an inter­dependency.   In this thesis work, we explore the possibility of moving the load balancing functionality to a Smart Network Interface Card (smartNIC). Our load balancer will distribute traffic among the set of CPUs where NF instances run. We will use P4 and C programming language in our design, which gives us the combination of high­speed parallel packet processing and the ability to implement relatively complex load balancing features. Our LB approach uses latency experienced by the packet as an estimate for the current CPU loading. In our design, higher latency is a sign of a more busy CPU. The Latency Aware smartNIC based Load Balancer (LASLB) also aims to reduce the tail latency by moving traffic from CPUs where traffic experiences high latency to CPU that processes traffic under low latency. The approach followed in the design does not require any statistics feedback support from the NF, which avoids the tight binding of LB with NF.   Our experiment on different traffic profiles has shown that LASLB can save ~30% CPU for NF. In terms of fairness of CPU loading, our evaluation indicates that in imbalanced traffic, the LASLB can load more evenly than other evaluated methods in smartNIC­ based LB category. Our evaluation also shows that LASLB can reduce 95th percentile tail latency by ~22% compared to software load balancing.

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The following master thesis is focused on creation of methodology for optimal usage of load balancing in data center environment. Thesis is divided into eight chapters. The first chapter describes the reasons why to deal with this topic further. The second chapter summarizes the state of load balancing. This chapter is based on research of already elaborated thesis which were focused on load balancing in different ways. The third chapter summarizes load balancing including its key principles. The fourth chapter describes an actual state of load balancing in data center environment. An observation of real usage of load balancing in selected data center was used for the main purpose of this chapter. The fifth chapter consists of analysis of the currently existing methodologies which are used from the infrastructure projects purpose. The sixth chapter deals with creation of methodology for optimal usage of load balancing in data center. The seventh chapter evaluates usage of methodology by applying of this methodology to real practical example of implementation of load balancing. The eighth chapter summarizes all detected conclusions.

This report compares the characteristics of push/pull load balancing techniques usedin the context of a logging system. The logging system is expected to handle a largevolume of events. The load balancing techniques are evaluated with focus onthroughput during high load. The testing scenarios includes the use of a traditionalload balancer (push-based) and the use of messaging queues (pull-based and indirectlycontext aware) in its place. The ultimate goal of the report is to determine the feasibilityof using a messaging queue rather than a traditional load balancer in a distributedlogging system. Tests were conducted measuring the throughput of multiple setupswith different load balancers. The conclusion of this report is that both messagingqueues and load balancing are equally feasible in a logging context. / Rapporten jämför egenskaper hos lastbalanseringstekniker för användning i ettdistribuerat logghanteringssystem. Systemet förväntas hantera stora volymermeddelanden vid hög belastning. Testscenarion som utförs sker med traditionelllastbalansering där event trycks ut, samt med meddelandeköer som är hämtbaserade.Målet med rapporten är att avgöra om kontextbaserad lastbalansering kan ökastabiliteten i ett system avsett för hantering av loggdata. Testerna som utfördesuppmätte mängden data som gick igenom systemet vid en given tidpunkt, testernakördes med flera typer av lastbalanserare. Slutsatsen som dras är att bådemeddelandeköer och lastbalansering är passande för användning i ett loggsystem.

Data Plane Development Kit is a highly used library for creating network applications that can be run on all hardware. Data Plane Development Kit has a component called Service Cores, which allows the main applications to create services that will run independently. These services are manually mapped to specific CPU cores, and are scheduled in a round-robin method. Because of the manual mapping, and the scheduling, the different load for each service can impact the start time for each service. By having services not run when supposed to, the throughput will degrade. In this thesis, we investigate and try to solve the issue by implementing a basic load balancer into the Service Core component. Our results show that an basic load balancer, that will balance upon reaching a CPU upper threshold, will increase the throughput of services while decreasing the delay between each service run.

A manipulação de materiais é uma das tarefas em que comumente empregam-se robôs para substituir o trabalho humano, dadas algumas vantagens como: maior precisão na manipulação de cargas e maior velocidade de execução da tarefa, bem como por aumentar a segurança do operador. Apesar dessas vantagens, os dispositivos robóticos são largamente empregados apenas em situações em que velocidade e precisão são indispensáveis, em outros casos, os equipamentos convencionais (como talhas, gruas e macacos hidráulicos) e os dispositivos específicos (aqueles fazem uso de molas e contrapesos), vêm sendo utilizados nas tarefas cotidianas, principalmente pelo fato de, entre outros, serem menos dispendiosos. Comparando-se estas duas soluções disponíveis, tem-se que os equipamentos tradicionais, apesar de sua simplicidade e versatilidade de movimentação, apresentam limitações quando são exigidas precisão e eficiência, enquanto os dispositivos robóticos apresentam alta complexidade tanto no projeto quanto na operação, representando uma solução cara e com movimentação restrita pela programação. Neste contexto, o presente trabalho tem por objetivo estudar e propor uma solução intermediária entre a solução convencional e a robótica. O foco do estudo é o projeto de um dispositivo simplificado, que faz uso de molas e de um sistema de alavanca para manipular cargas. Um estudo preliminar desse mecanismo mostrou imperfeições quanto à força de contrabalanceamento. Com o intuito de corrigir esse erro foi usado um sistema de controle, que é constituído por um motor elétrico, um mecanismo de correção, sensores e um módulo controlador. O dispositivo proposto apresenta um controle simplificado, vez que a movimentação é feita exclusivamente pelo operador, possibilitando assim que o dispositivo apresente um baixo consumo de energia. Um protótipo é desenvolvido e os testes demonstraram a eficácia da solução. / The material handling is one task in which robot is commonly employed to replace the human work because it has some advantages such as, higher precision in the handling and higher speed of the task, and to increase operator safety. Despite these advantages, the robotic device is most employed only in situation that speed and precision are essential; in other cases, the conventional equipments (such as hydraulic jacks, cranes and pulley systems) and the specific device (which use springs and counterweight), have been used in daily tasks mainly because of they are less expensive. Comparing these two solutions, it is possible to say that the conventional devices, despite its simplicity and guidance, have limitations when the task requires precision and speed, while the robotic solution has higher complexity in both design and in operation, representing an expensive solution with a programming that restrict the movement. In this context, the present work has the objective the study and development of an intermediate solution between the conventional solution and the robotic device. The proposed study is based on a simplified device, which uses springs and a lever system to handle material. A preliminary study on this mechanism shows imperfections in balance force. In order to correct this error, a control system is used. The control system is constituted by an electric motor, a correcting mechanism, sensors and a controller. The proposed device presents simple control because movements are responsibility of the human operator moreover presents low power consumption, due to the use of springs. A prototype is developed and tests demonstrate the effectiveness of the solution.

Systems that process big data (e.g., high-traffic networks and large-scale storage) prefer data structures and algorithms with small memory and fast processing speed. Efficient and fast algorithms play an essential role in system design, despite the improvement of hardware. This dissertation is organized around a novel algorithm called Othello Hashing. Othello Hashing supports ultra-fast and memory-efficient key-value lookup, and it fits the requirements of the core algorithms of many large-scale systems and big data applications. Using Othello hashing, combined with domain expertise in cloud, computer networks, big data, and bioinformatics, I developed the following applications that resolve several major challenges in the area. Concise: Forwarding Information Base. A Forwarding Information Base is a data structure used by the data plane of a forwarding device to determine the proper forwarding actions for packets. The polymorphic property of Othello Hashing the separation of its query and control functionalities, which is a perfect match to the programmable networks such as Software Defined Networks. Using Othello Hashing, we built a fast and scalable FIB named \textit{Concise}. Extensive evaluation results on three different platforms show that Concise outperforms other FIB designs. SDLB: Cloud Load Balancer. In a cloud network, the layer-4 load balancer servers is a device that acts as a reverse proxy and distributes network or application traffic across a number of servers. We built a software load balancer with Othello Hashing techniques named SDLB. SDLB is able to accomplish two functionalities of the SDLB using one Othello query: to find the designated server for packets of ongoing sessions and to distribute new or session-free packets. MetaOthello: Taxonomic Classification of Metagenomic Sequences. Metagenomic read classification is a critical step in the identification and quantification of microbial species sampled by high-throughput sequencing. Due to the growing popularity of metagenomic data in both basic science and clinical applications, as well as the increasing volume of data being generated, efficient and accurate algorithms are in high demand. We built a system to support efficient classification of taxonomic sequences using its k-mer signatures. SeqOthello: RNA-seq Sequence Search Engine. Advances in the study of functional genomics produced a vast supply of RNA-seq datasets. However, how to quickly query and extract information from sequencing resources remains a challenging problem and has been the bottleneck for the broader dissemination of sequencing efforts. The challenge resides in both the sheer volume of the data and its nature of unstructured representation. Using the Othello Hashing techniques, we built the SeqOthello sequence search engine. SeqOthello is a reference-free, alignment-free, and parameter-free sequence search system that supports arbitrary sequence query against large collections of RNA-seq experiments, which enables large-scale integrative studies using sequence-level data.

A manipulação de materiais é uma das tarefas em que comumente empregam-se robôs para substituir o trabalho humano, dadas algumas vantagens como: maior precisão na manipulação de cargas e maior velocidade de execução da tarefa, bem como por aumentar a segurança do operador. Apesar dessas vantagens, os dispositivos robóticos são largamente empregados apenas em situações em que velocidade e precisão são indispensáveis, em outros casos, os equipamentos convencionais (como talhas, gruas e macacos hidráulicos) e os dispositivos específicos (aqueles fazem uso de molas e contrapesos), vêm sendo utilizados nas tarefas cotidianas, principalmente pelo fato de, entre outros, serem menos dispendiosos. Comparando-se estas duas soluções disponíveis, tem-se que os equipamentos tradicionais, apesar de sua simplicidade e versatilidade de movimentação, apresentam limitações quando são exigidas precisão e eficiência, enquanto os dispositivos robóticos apresentam alta complexidade tanto no projeto quanto na operação, representando uma solução cara e com movimentação restrita pela programação. Neste contexto, o presente trabalho tem por objetivo estudar e propor uma solução intermediária entre a solução convencional e a robótica. O foco do estudo é o projeto de um dispositivo simplificado, que faz uso de molas e de um sistema de alavanca para manipular cargas. Um estudo preliminar desse mecanismo mostrou imperfeições quanto à força de contrabalanceamento. Com o intuito de corrigir esse erro foi usado um sistema de controle, que é constituído por um motor elétrico, um mecanismo de correção, sensores e um módulo controlador. O dispositivo proposto apresenta um controle simplificado, vez que a movimentação é feita exclusivamente pelo operador, possibilitando assim que o dispositivo apresente um baixo consumo de energia. Um protótipo é desenvolvido e os testes demonstraram a eficácia da solução. / The material handling is one task in which robot is commonly employed to replace the human work because it has some advantages such as, higher precision in the handling and higher speed of the task, and to increase operator safety. Despite these advantages, the robotic device is most employed only in situation that speed and precision are essential; in other cases, the conventional equipments (such as hydraulic jacks, cranes and pulley systems) and the specific device (which use springs and counterweight), have been used in daily tasks mainly because of they are less expensive. Comparing these two solutions, it is possible to say that the conventional devices, despite its simplicity and guidance, have limitations when the task requires precision and speed, while the robotic solution has higher complexity in both design and in operation, representing an expensive solution with a programming that restrict the movement. In this context, the present work has the objective the study and development of an intermediate solution between the conventional solution and the robotic device. The proposed study is based on a simplified device, which uses springs and a lever system to handle material. A preliminary study on this mechanism shows imperfections in balance force. In order to correct this error, a control system is used. The control system is constituted by an electric motor, a correcting mechanism, sensors and a controller. The proposed device presents simple control because movements are responsibility of the human operator moreover presents low power consumption, due to the use of springs. A prototype is developed and tests demonstrate the effectiveness of the solution.

Slow rate Denial of Service (DoS) attacks have been shown to be a very effective way of attacking vulnerable servers while using few resources. This thesis investigates the effectiveness of mitigation tools used for protection against slow DoS attacks, specifically slowheader and slow body. Finally, we propose a service that cloud providers could implement to ensure better protection against slow rate DoS attacks. The tools studied in this thesis are, a Web Application firewall, a reverse proxy using an event-based architecture and Amazon’s Elastic Load Balancing. To gather data a realistic HTTP load script was built that simulated load on the server while using probe requests to gather response time data from the server. The script recorded the impact the attacks had for each server configuration.The results show that it’s hard to protect against slow rate DoS attacks while only using firewalls or load balancers. We found that using a reverse proxy with an event-based architecture was the best way to protect against slow rate DoS attacks and that such a service would allow the customer to use their server of choice while also being protected.