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Redundance v datových sítích / Redundancy in data networksŠoun, Jan January 2010 (has links)
This thesis focuses on redundancy in data networks and on technologies which are used to achieve high availability in network infrastructure. This thesis is based on industry standards published by well-known standardization authorities. One proprietary technology which can effectively replace these standards and simplify the whole network is also presented in more detail. The theoretical part individually describes all such technologies and standards. The practical part deals with an appropriate combination of these technologies and their application in a specific product environment. This work is meant to describe the whole concept of high availability in network infrastructure and should be instrumental in understanding how these technologies are deployed in practice.
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QoS v síti VŠE / QoS in a computer network of VŠEKalina, Tomáš January 2012 (has links)
The diploma thesis is focused on analysis and deployment of Quality of Services (QoS) in a computer network of The University of Economics in Prague (VŠE). The thesis describes the main QoS technologies focusing on technology Diffserv and its deployment with using available network devices in computer network of VŠE. In thesis the needs of network services and protocols for quality of services with division into different classes of services according to priority are discussed. The thesis explains the benefits and drawbacks of deploying QoS in the environment of VŠE with regard to wired and wireless network. In the practical part recommendations are applied to the production network and subsequently the benefits of modification are evaluated.
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Serviços de pertinência para clusters de alta disponibilidade / Membership Services for High Availability ClustersNelio Alves Pereira Filho 20 August 2004 (has links)
Desde sua criação, o Linux trouxe muita atenção ao movimento open-source, e à concreta possibilidade de se usar soluções de baixo custo em missões críticas. Nos últimos anos, esta possibilidade tornou-se real com a criação de vários clusters de alta disponibilidade. Atualmente, existem pelo menos 10 soluções de clusters open-source e mais de 25 comerciais. Cada um destes projetos teve uma abordagem diferente para o problema, embora todos tenham enfrentado dificuldades semelhantes. Se houvesse alguma padronização nesta área, esforços poderiam ter sido reaproveitados, e não duplicados. Neste contexto, o Open Clustering Framework (OCF) é um projeto open-source que visa definir um padrão para clusters em Linux. Um dos serviços mais importantes em um cluster é o serviço de pertinência. Ele é responsável por criar e manter o grupo, sendo assim importante para inúmeras aplicações. Sistemas de alta disponibilidade baseiam-se no serviço de pertinência para garantir o funcionamento dos recursos oferecidos por um cluster. Esta dissertação visa apresentar vários conceitos relativos a clusters, alta disponibilidade e serviços de pertinência. Com estes conceitos definidos, iremos implementar um serviço de pertinência, que será baseado no framework proposto pelo OCF, de maneira que esta implementação possa ser posteriormente incorporada a qualquer cluster que siga a especificação OCF. / Since its creation, Linux has brought attention to the open-source movement, and to the concrete possibility of using low cost solutions in critical mission systems. In the last years, this possibility has become real due to the creation of several high availability clusters. Today there are at least 10 open-source solutions and more than 25 commercial ones. Each one of these projects had a different approach to the problem, altought all of them had faced similar difficulties. If there was a standard in this area, efforts could be shared, and not duplicated. In this context, the Open Clustering Framework (OCF) is an open-source project that aims to define a cluster standard for Linux. One of the more important services in a cluster is the membership service. It is responsible for creating and maintaing the group. For this reason, it is important for many applications: high availability systems rely on this service to garantee the execution of the resources provided by a cluster. This thesis aims to present several concepts related to clusters, high availability and membership services. Having the concepts been defined, we will implement a membership service based on the OCF framework, in order to be able to incorporate this implementation in any OCF compliant cluster.
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Návrh a implementace SAP CAR s automatickým zotavením z havárie / Design and Implementation of SAP CAR with Automatic Disaster Recovery FunctionSvitálek, Petr January 2017 (has links)
The main purpose of this master's thesis is to propose and implement a SAP CAR (customer activity repository) solution as an application into the current enterprise information system. Following the analysis of the existing system, there will be a solution created, which is fulfilling the customer demands and at the same time it is feasible under given conditions and in the current environment. This project is closely related with addressing the disaster recovery issue for making the system highly available. The final design is implemented, tested and then handed over to the customer.
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Virtualizace a optimalizace IT v produkční společnosti / Virtualisation and Optimalisation of IT in a Production CompanyPopelka, David January 2013 (has links)
The master‘s thesis deals with the implementation of server virtualization in the Entity production, s.r.o., which is a small company by it’s size, but needs modern IT technologies for the normal operations. The thesis shows how to reuse the server virtualization technologies from large corporations, that have been unavailable to small business companies in past. It also design show to optimize the current IT environment.
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Reaching High Availability in Connected Car Backend ApplicationsYadav, Arpit 23 May 2017 (has links)
The connected car segment has high demands on the exchange of data between the car on the road, and a variety of services in the backend. By the end of 2020, connected services will be mainstream automotive offerings, according to Telefónica - Connected Car Industry Report 2014 the overall number of vehicles with built-in internet connectivity will increase from 10% of the overall market today to 90% by the end of the decade [1]. Connected car solutions will soon become one of the major business drivers for the industry; they already have a significant impact on existing solutions development and aftersales market.
It has been more than three decades since the introduction of the first software component in cars, and since then a vast amount of different services has been introduced, creating an ecosystem of complex applications, architectures, and platforms. The complexity of the connected car ecosystem results into a range of new challenges. The backend applications must be scalable and flexible enough to accommodate loads created by the random user and device behavior. To deliver superior uptime, back-end systems must be highly integrated and automated to guarantee lowest possible failure rate, high availability, and fastest time-to-market.
Connected car services increasingly rely on cloud-based service delivery models for improving user experiences and enhancing features for millions of vehicles and their users on a daily basis. Nowadays, the software applications become more complex, and the number of components that are involved and interact with each other is extremely large. In such systems, if a fault occurs, it can easily propagate and can affect other components resulting in a complex problem which is difficult to detect and debugg, therefore a robust and resilient architecture is needed which ensures the continuous availability of system in the wake of component failures, making the overall system highly available.
The goal of the thesis is to gain insight into the development of highly available applications and to explore the area of fault tolerance. This thesis outlines different design patterns and describes the capabilities of fault tolerance libraries for Java platform, and design the most appropriate solution for developing a highly available application and evaluate the behavior with stress and load testing using Chaos Monkey methodologies.
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Study of mechanisms ensuring service continuity for IKEv2 and IPsec protocols / Étude de mécanismes assurant la continuité de service de protocoles IKEv2 et IPsecPalomares Velasquez, Daniel 14 November 2013 (has links)
En 2012, le trafic mobile mondial représentait 70% de plus qu'en 2011. L'arrivée de la technologie 4G a multiplié par 19 le volume de trafic non 4G, et en 2013 le nombre de mobiles connectés à l'Internet a dépassé le nombre d'êtres humains sur la planète. Les fournisseurs d'accès Internet (FAI) subissent une forte pression, car ils ont pour obligations d'assurer à leurs clients l'accès au réseau et le maintien de la qualité de service. À court/moyen terme, les opérateurs doivent délester une partie de leur trafic sur des réseaux d'accès alternatifs afin de maintenir les mêmes caractéristiques de performances. Ainsi, pour désengorger les réseaux d'accès radio (RAN), le trafic des clients peut être préférentiellement pris en charge par d'autres réseaux d'accès disponibles. Notons cependant que les réseaux d'accès sans fil offrent des niveaux de sécurité très différents. Pour les femtocells, WiFi ou WiMAX (parmi d'autres technologies sans fil), il doit être prévu des mécanismes permettant de sécuriser les communications. Les opérateurs peuvent s'appuyer sur des protocoles (tels que IPsec) afin d'étendre un domaine de sécurité sur des réseaux non sécurisés. Cela introduit de nouveaux défis en termes de performances et de connectivité pour IPsec. Cette thèse se concentre sur l'étude des mécanismes permettant de garantir et améliorer les performances du protocole IPsec en termes de continuité de service. La continuité de service, aussi connu comme résilience, devient cruciale lorsque le trafic mobile est dévié depuis un réseau d'accès RAN vers d'autres réseaux d'accès alternatifs. C'est pourquoi nous nous concentrons d'abord dans l'ensemble de protocoles assurant une communication IP: IKEv2 et IPsec. Ensuite, nous présentons une étude détaillée des paramètres nécessaires pour maintenir une session VPN, et nous démontrons qu'il est possible de gérer dynamiquement une session VPN entre différentes passerelles de sécurité. L'une des raisons qui justifient la gestion des sessions VPN est d'offrir de la haute disponibilité, le partage de charge ou l'équilibrage de charge pour les connexions IPsec. Ces mécanismes ont pour finalité d'augmenter la continuité de service de sessions IPsec. Certains nouveaux mécanismes ont été récemment mis en oeuvre pour assurer la haute disponibilité sur IPsec. Le projet open source VPN, StrongSwan, a mis en place un mécanisme appelé ClusterIP afin de créer un cluster de passerelles IPsec. Nous avons fusionné cette solution basée sur ClusterIP avec nos propres développements afin de définir deux architectures : une architecture permettant la Haute Disponibilité et une deuxième architecture présentant la gestion dynamique d'un contexte IPsec. Nous avons défini deux environnements : le Mono-LAN où un cluster de noeuds est configuré sous une même adresse IP unique, et le Multi-LAN où chaque passerelle de sécurité dispose d'une adresse IP différente. Les mesures de performance tout au long de la thèse montrent que le transfert d'une session VPN entre différentes passerelles évite les délais supplémentaires liés à la ré-authentification et réduit la consommation CPU, ainsi que les calculs par le matériel cryptographique. D'un point de vue FAI, le transfert de contexte IPsec/IKEv2 pourrait être utilisé pour éviter la surcharge des passerelles, et permettre la redistribution de la charge, de meilleures performances du réseau ainsi que l'amélioration de la qualité de service. L'idée est de permettre à un utilisateur de profiter de la continuité d'un service tout en conservant le même niveau de sécurité que celui initialement proposé / During 2012, the global mobile traffic represented 70\% more than 2011. The arrival of the 4G technology introduced 19 times more traffic than non-4G sessions, and in 2013 the number of mobile-connected to the Internet exceeded the number of human beings on earth. This scenario introduces great pressure towards the Internet service providers (ISPs), which are called to ensure access to the network and maintain its QoS. At short/middle term, operators will relay on alternative access networks in order to maintain the same performance characteristics. Thus, the traffic of the clients might be offloaded from RANs to some other available access networks. However, the same security level is not ensured by those wireless access networks. Femtocells, WiFi or WiMAX (among other wireless technologies), must rely on some mechanism to secure the communications and avoid untrusted environments. Operators are mainly using IPsec to extend a security domain over untrusted networks. This introduces new challenges in terms of performance and connectivity for IPsec. This thesis concentrates on the study of the mechanism considering improving the IPsec protocol in terms of continuity of service. The continuity of service, also known as resilience, becomes crucial when offloading the traffic from RANs to other access networks. This is why we first concentrate our effort in defining the protocols ensuring an IP communication: IKEv2 and IPsec. Then, we present a detailed study of the parameters needed to keep a VPN session alive, and we demonstrate that it is possible to dynamically manage a VPN session between different gateways. Some of the reasons that justify the management of VPN sessions is to provide high availability, load sharing or load balancing features for IPsec connections. These mechanisms increase the continuity of service of IPsec-based communication. For example, if for some reason a failure occurs to a security gateway, the ISP should be able to overcome this situation and to provide mechanisms to ensure continuity of service to its clients. Some new mechanisms have recently been implemented to provide High Availability over IPsec. The open source VPN project, StrongSwan, implemented a mechanism called ClusterIP in order to create a cluster of IPsec gateways. We merged ClusterIP with our own developments in order to define two architectures: High Availability and Context Management over Mono-LAN and Multi-LAN environments. We called Mono-LAN those architectures where the cluster of security gateways is configured under a single IP address, whereas Multi-LAN concerns those architectures where different security gateways are configured with different IP addresses. Performance measurements throughout the thesis show that transferring a VPN session between different gateways avoids re-authentication delays and reduce the amount of CPU consumption and calculation of cryptographic material. From an ISP point of view, this could be used to avoid overloaded gateways, redistribution of the load, better network performances, improvements of the QoS, etc. The idea is to allow a peer to enjoy the continuity of a service while maintaining the same security level that it was initially proposed
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An Internship in Technical and Scientific Communication with Dell IncHawkins, Steve 11 December 2003 (has links)
No description available.
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A Highly-Available Multiple Region Multi-access Edge Computing Platform with Traffic FailoverSulaeman, Adika Bintang January 2020 (has links)
One of the main challenges in the Multi-access Edge Computing (MEC) issteering traffic from clients to the nearest MEC instances. If the nearest MECfails, a failover mechanism should provide mitigation by steering the trafficto the next nearest MEC. There are two conventional approaches to solve thisproblem, i.e., GeoDNS and Internet Protocol (IP) anycast. GeoDNS is notfailover friendly because of the Domain Name System (DNS) cache lifetime.Moreover, the use of a recursive resolver may inaccurately translate the IPaddress to its geolocation. Thus, this thesis studies and proposes a highlyavailable MEC platform leveraging IP anycast. We built a proof-of-conceptusing Kubernetes, MetalLB, and a custom health-checker running on theGNS3 network emulator. We measured latency, failure percentage, and MeanTime To Repair (MTTR) to observe the system’s behavior. The performanceevaluation of the proposed solution shows an average recovery time betterthan one second. The number of failed requests and latency overhead growslinearly as the failover time and latency between two MECs increases. Thisthesis demonstrates the effectiveness of IP anycast for MEC applications tosteer the traffic to the nearest MEC instance and to enhance resiliency withminor overhead. / n av de största utmaningarna i Multi-access Edge Computing (MEC) är attstyra trafiken från klienter till närmaste MEC instanser. Om den närmasteMEC misslyckas, bör en failover-mekanism ge begränsning genom att styratrafiken till nästa närmaste MEC. Det finns två konventionella metoder för attlösa detta problem, dvs GeoDNS och IP anycast. GeoDNS är inte failovervänligtpå grund av DNS-cache-livslängd. Dessutom kan användningen aven rekursiv upplösare felaktigt översätta IP-adressen till dess geolokalisering.Således studerar och föreslår denna avhandling en mycket tillgänglig MEC-plattform som utnyttjar IP anycast. Vi byggde ett proof-of-concept medKubernetes, MetalLB och en anpassad hälsokontroll som körs på GNS3-nätverksemulatorn. Vi mätte latens, felprocent och Mean Time To Repair(MTTR) för att observera systemets beteende. Prestationsutvärderingen avden föreslagna lösningen visar en genomsnittlig återhämtningstid som ärbättre än en sekund. Antalet misslyckade förfrågningar och latensomkostnaderväxer linjärt när failover-tiden och latensen mellan två MEC ökar. Den häravhandlingen visar effektiviteten hos IP anycast för MEC-applikationer för attstyra trafiken till närmaste MEC instans och för att förbättra elasticiteten medmindre overhead.
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Replikerings- och Klusterlösning för PostgreSQLEriksson, Jesper January 2024 (has links)
Många organisationer världen över är i behov av att förmedla data lagrade i databaser till sina kunder samt ta emot information av kunden som lägger till/tar bort data i databasen. Att kunna ha databastjänsterna tillgängliga åt kunden under olika omständigheter och behandla kundens transaktion mot databasen snabbt är något som gynnar organisationen. Detta är särskilt viktigt för den svenska myndigheten Bolagsverket. För detta ändamål kan flera databaservrar interagera med varandra genom replikering, vilket resulterar i ett serverkluster av flera sammankopplade noder. I arbetet utforskades det om servrar med Postgres kan möta myndighetens behov. Målet med arbetet är att utifrån en skapad sammanställning av vilka områden som önskas utforskas, att demonstrera om Postgres har vad som krävs för att möta områdets kriterier och slutligen utvärdera utfallet av demonstrationen. Arbetet resulterade i tre sammanställda områden, totalt 12 implementationer över samtliga områden sammanlagt samt 6 av dem som mötte de kriterier för det område som behandlades. I arbetet tillämpades för samtliga implementeringar en direkt/indirekt fysisk replikering, som bygger på att en av noderna kan skrivas åt i taget där förändringen replikeras direkt till övriga noder. I samband med implementering användes ett flertal av Postgres tillägg och externa utbyggnader. Det beslutades under arbetets förlopp att endast behandla två av dessa områden fullständigt till förmån för utförlighet. Slutsatsen drogs att för de två områdena som behandlades fullständigt så hade Postgres förmågan att möta kriterierna. Dessutom så drogs slutsatsen att om en implementering avsedd för det tredje området kunde möta de sammanställda kriterierna så har Postgres det som krävs för att möta myndighetens behov. / Many organizations worldwide are in need of conveying data stored in databases to their customers as well as receiving information from the customer who adds/deletes data in the database. Being able to have the database services available to the customer in various circumstances and to process the customers transaction against the database quickly is something that benefits the organization. This is particularly of importance for the authority of the Swedish Companies Registration Office (Bolagsverket). For this purpose, several database servers can interact with each other through replication, resulting in a server cluster of several interconnected nodes. The work explored whether servers with Postgres can meet Bolagsverkets needs. The goal of the work consisted of three parts. To define what areas to explore and related mandatory criterias. Create solutions based on the previous step. And finally demonstrate that Postgres has what it takes to meet the areas criterias. The work resulted in three areas, a total of 12 implementations across all areas combined, in of which 6 of them met the mandatory criterias. In the work, a direct/indirect physical replication was applied in all implementations. In physical replication one of the nodes can be written to at a time, where the change is replicated directly to the other nodes. Within implementation, a number of official and external Postgres tools/extensions were used combined with Postgres base functionality. It was decided during the course of the work to treat only two of these areas in full in favor of extensive work. It was concluded that for the two areas that were fully addressed, Postgres had the ability to meet the criterias. In addition, it was concluded that if an implementation intended for the third area could meet the criterias, then Postgres has what it takes to meet the authority needs.
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