The master’s thesis deals with computer networks, which are currently the global communication infrastructure and play a very important role in today’s society. Most of us can be unaware of how often we interact with these networks. We almost constantly come into contact with them. They allow us to communicate through the Internet via services such as: email, skype, icq, facebook, etc... The work focuses on the design and implementation of a robot designed for exploration and mapping of computer network topology and protocols HTTP and ICMP. The theoretical part is dedicated to computer networks, seventh and third-layer ISO/OSI model, protocol HTTP and ICMP attacks against DNS, DoS attacks and detection systems and avoiding distortaions.

The objective of this thesis is creating a design of a redundant secure VPN WAN network for Medical Emergency Service of Pardubice region. The starting point of this thesis is the analysis of the current state of the corporate computer network, which was evaluated as not satisfying. The result is a design of WAN network, which satisfies the requirements of the investor. The solution also includes the project of implementation and financial calculation of the project.

Master thesis deals with the design of network topologies with multiple redundant links for investor’s local area network. The objective of the thesis is to design more topology proposals according to investor’s requirements and applied technologies. Design is based on an analysis of the current state, which describes current topology of investor’s network. The main part of the thesis proposes a solution based on currently available network redundancy protocols. The functionality of the proposed solutions is tested in laboratory conditions. Finally, the individual variants are compared and their individual benefits evaluated.

Information dissemination is an important issue for mobile ad-hoc communities. This issue is very challenging due to the dynamic and fragile nature of the mobile ad-hoc networks, in which participants have limited computing resources and battery, intermittent network connections, and mobile tasks. To address the aforementioned issue, this thesis proposes an efficient semantics-based publish/subscribe strategy. In our proposed publish/subscribe system, distributed mobile participants are organized into clusters based on their location proximity. A compact semantics-based indexing scheme is provided to guide information flow. Intra- and inter- cluster routings are proposed to assist efficient propagation of event notifications. A comprehensive set of simulation experiments prove the effectiveness of the proposed scheme.

This master's thesis focuses on optimizing the network tracking tool Zabbix. In the first part this thesis provides an overview of techniques used for monitoring computer networks. The thesis also describes the fundamentals of how Zabbix works, especially in large enviroments. In the second part of the thesis we compare existing optimizations of the database structure which divides large, parent tables into small partitions. The most suitable solution is chosen which is then modified for the BUT network needs. Using this optimization we achieved a decrease of the processor utilization on the Zabbix server and a significant decrease in the growth of data on its hard drive.

Computing in a heterogeneous environment requires an exchange of information among computers which have different ways of representing information. This type of information exchange demands a standard external data representation. One such standard, Abstract Syntax Notation One (ASN.l), is defined by the International Organization for Standardization (ISO) and its transfer syntax, the Basic Encoding Rules (BER). This project presents the design of a C++ class hierarchy modeling the concepts presented in ASN.l and encapsulating the BER encoding rules. The goal of this class hierarchy is to utilize the rich features of object-oriented paradigm to provide a clean and simple interface for OSI presentation layer protocols to application developers and implementors. This report discusses the class hierarchy in detail and shows how the primitive and constructed ASN.l types are defined, encoded and decoded using this hierarchy. / Master of Science

Cloud providers need to optimize the container deployments to efficiently utilize their network, compute and storage resources. In addition, they require an attractive pricing strategy for the compute services like containers, virtual machines, and serverless computing in order to attract users, maximize their profits and achieve a desired utilization of their resources. This thesis aims to tackle the twofold challenge of achieving high performance in container deployments and identifying the pricing for compute services. For performance, the thesis presents a transport-adaptive network architecture (D-TAIL) improving tail latencies. Existing transport protocols such as Homa, pFabric [1, 2] utilize Shortest Remaining Processing Time (SRPT) scheduling policy which is known to have starvation issues for long flows as SRPT prioritizes short flows. D-TAIL addresses this limitation by taking age of the flow in consideration while deciding the priority. D-TAIL shows a maximum reduction of 72%, 29.66% and 28.39% in 99th-percentile FCT for transport protocols like DCTCP, pFabric and Homa respectively. In addition, the thesis also presents a container deployment design utilizing peer-to-peer network and virtual file system with content-addressable storage to address the problem of cold starts in existing container deployment systems. The proposed deployment design increases compute availability, reduces storage requirement and prevents network bottlenecks. For pricing, the thesis studies the tradeoffs between serverless computing (SC) and traditional cloud computing (virtual machine, VM) using realistic cost models, queueing theoretic performance models, and a game theoretic formulation. For customers, we identify their workload distribution between SC and VM to minimize their cost while maintaining a particular performance constraint. For cloud provider, we identify the SC and VM prices to maximize its profit. The main result is the identification and characterization of three optimal operational regimes for both customers and the provider, that leverage either SC or VM only, or both, in a hybrid configuration.

Indiana University-Purdue University Indianapolis (IUPUI) / The study of this thesis is focused on reducing the link failure detection time in OSPF network. When a link failure occurs, OSPF protocol detects it using RouterDeadInterval time. This timer is fired only after a predefined time interval, thus increasing the time of convergence after the link failure. There are previous studies to reduce the RouterDeadInterval time, but they introduce other effects which are discussed later in the thesis. So, a novel approach is proposed in this thesis to reduce the link failure detection time with the help of emerging network architecture Software Defined Networking (SDN) and OpenFlow Protocol.

A research report submitted in partial fulfilment to the Degree of Master of Commerce (Information Systems) in the school of Economic and Business Sciences, University of the Witwatersrand, 2018 / Purpose: The aim in this research study was to explore the role and competencies of Data Scientists in South Africa as the role starts to emerge. Due to the newness of the role, jobs in this sphere are currently being filled by skilled professionals moving from other related areas. Knowledge and skills for Data Scientists were explored in order to examine the role of a Data Scientist and the competencies they should have. Design/methodology/approach: The studies that have been published on the role of a Data Scientist are limited as the field of Data Science is still new. Therefore the design of the research was exploratory and used qualitative methods. Data gathered for this research was analysed using thematic analysis. The study used respondents drawn from the banking and insurance industries as they are amongst the first to employ Data Scientists in the real sense of the term in South Africa. Six Data Scientists were interviewed. Originality/value: Research that focuses on the role of Data Scientists especially in South Africa is limited as most of the research has taken place in developed countries. There is also limited research on the role of a Data Scientist within the banking and insurance industry. This study contributes to practitioner and research knowledge by exploring the emerging role of a Data Scientist in the South African context. Practical implications: This research improves our understanding of the knowledge and skills Data Scientists should have within the banking and insurance industry. This research adds insight by highlighting the role that Data Scientists are currently undertaking by providing information on the specific skills that they report as required. This research can help in the shaping of education and developing the required skills for individuals who intend to pursue the career path of a Data Scientist as well as help managers hire the right people for the position of a Data Scientist. / TL2019

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