Our study on interdomain traffic engineering focuses on AS Path Prepending (ASPP), a popular way for inbound traffic engineering. In order to improve the current situation that ISPs often practise this approach in a trial-and-error basis, we propose a greedy algorithm to help ISPs perform this approach systematically and efficiently. Then we demonstrate two fundamental issues of decentralized selfish traffic engineering, routing instability and global network performance degradation, based on an abstract model where ISPs perform traffic engineering for their individual load balance. We also present a real-world pathologic case of prepending instability from our measurement study. Some simple guidelines are given for ISPs to avoid such routing instability. / Our work on peering strategy is to help ISPs understand the economic implications of various traffic patterns and make proper decisions to optimize their business. We first conduct an economic analysis for an overlay streaming network to gain some insights on the free ride phenomenon. We further improve the analysis by taking the response of subscribers into consideration and formulate the dynamic market as a multi-leader-follower game to capture the Nash Equilibrium of the routing tussle among the major players of the Internet marketplace. Based on this framework together with a gravity traffic model, we present some important observations on the implications of overlays on ISPs' peering strategy. / Over the past several years, numerous types of "overlay" networks change the interdomain traffic pattern and ISPs lose the routing control of some interdomain traffic flows due to the application layer routing. As a result, some ISPs may provide unintended transit service for other local ISPs. It upsets the traditional business model and makes ISPs' peering strategies more complicated. / The Internet has quickly evolved into a vast global network owned and operated by thousands of interconnected Internet Service Providers. Each of these ISPs, as one autonomous system, has its individual economic interests. ISPs can achieve their objectives through peering strategy and interdomain traffic engineering. These two issues are important for ISPs' business and have significant implications on the Internet architecture. / Wang, Hui. / "September 2007." / Adviser: Dah Ming Chiu. / Source: Dissertation Abstracts International, Volume: 69-08, Section: B, page: 4865. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (p. 163-170). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

by Guo, Xiao-Lei. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (p. 138-[147]). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.

Choi, Fu Wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (p. 54-57). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.2 / Chapter 2 --- Overview --- p.5 / Chapter 2.1 --- Summary of our Router Virtualization Architecture --- p.6 / Chapter 3 --- LVRM Design --- p.9 / Chapter 3.1 --- Socket Adapter --- p.9 / Chapter 3.2 --- VR Monitor --- p.11 / Chapter 3.3 --- VRI Monitor --- p.14 / Chapter 3.4 --- VRI Adapter --- p.16 / Chapter 3.5 --- Inter-Process Communication (IPC) Queue --- p.17 / Chapter 3.6 --- LVRM Adapter for VRI --- p.17 / Chapter 3.7 --- VRI --- p.18 / Chapter 3.8 --- Interfacing Between LVRM and VRs --- p.18 / Chapter 4 --- Experiments --- p.20 / Chapter 4.1 --- Experimental Setup --- p.20 / Chapter 4.2 --- Performance Overhead of LVRM --- p.23 / Chapter 4.3 --- Core Allocation --- p.31 / Chapter 4.4 --- Load Balancing --- p.38 / Chapter 4.5 --- Scalability --- p.43 / Chapter 4.6 --- Lessons Learned --- p.47 / Chapter 5 --- Related Work --- p.50 / Chapter 6 --- Conclusions --- p.52

Leung Ka Hing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 94-96). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Characterization and Performance Analysis --- p.8 / Chapter 2.1 --- Two-class Proportional Differentiated Service --- p.11 / Chapter 2.2 --- N-class Proportional DS --- p.13 / Chapter 3 --- Experiments of Proportional Delay Differentiation using the It- erative Algorithm --- p.20 / Chapter 3.1 --- Experiments using Poisson arrivals --- p.21 / Chapter 3.2 --- Experiments using other arrivals distributions --- p.33 / Chapter 4 --- Dynamic Adjustment --- p.37 / Chapter 4.1 --- Adjustment algorithms --- p.37 / Chapter 5 --- Experiments of Proportional Delay Differentiation using Dy- namic Adjustment --- p.41 / Chapter 5.1 --- Illustration of dynamic adjustment --- p.43 / Chapter 5.2 --- Poisson --- p.45 / Chapter 5.3 --- Pareto --- p.48 / Chapter 5.4 --- MMPP --- p.54 / Chapter 5.5 --- Heterogeneous traffic classes --- p.60 / Chapter 5.6 --- Experiments for short time-scale analysis --- p.62 / Chapter 6 --- Multiple nodes --- p.69 / Chapter 7 --- Summary of the Experiments Results --- p.75 / Chapter 8 --- Improvement of WTP --- p.78 / Chapter 8.1 --- Algorithm --- p.78 / Chapter 8.2 --- Experiments --- p.80 / Chapter 9 --- Possible Extensions --- p.85 / Chapter 9.1 --- Application Extension --- p.85 / Chapter 9.2 --- Performance Quantification --- p.87 / Chapter 10 --- Conclusion --- p.90

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Distributed media streaming has been driven by the combination of improved media compression techniques and an increase in the availability of bandwidth. This increase has lead to the development of various streaming distribution engines (systems/services), which currently provide the majority of the streaming media available throughout the Internet. This study aimed to analyse a range of existing commercial and open-source streaming media distribution engines, and classify them in such a way as to define a Common Analysis Framework for Simulated Streaming-Video Networks (CAFSS-Net). This common framework was used as the basis for a simulation tool intended to aid in the development and deployment of streaming media networks and predict the performance impacts of both network configuration changes, video features (scene complexity, resolution) and general scaling. CAFSS-Net consists of six components: the server, the client(s), the network simulator, the video publishing tools, the videos and the evaluation tool-set. Test scenarios are presented consisting of different network configurations, scales and external traffic specifications. From these test scenarios, results were obtained to determine interesting observations attained and to provide an overview of the different test specications for this study. From these results, an analysis of the system was performed, yielding relationships between the videos, the different bandwidths, the different measurement tools and the different components of CAFSS-Net. Based on the analysis of the results, the implications for CAFSS-Net highlighted different achievements and proposals for future work for the different components. CAFSS-Net was able to successfully integrate all of its components to evaluate the different streaming scenarios. The streaming server, client and video components accomplished their objectives. It is noted that although the video publishing tool was able to provide the necessary compression/decompression services, proposals for the implementation of alternative compression/decompression schemes could serve as a suitable extension. The network simulator and evaluation tool-set components were also successful, but future tests (particularly in low bandwidth scenarios) are suggested in order to further improve the accuracy of the framework as a whole. CAFSS-Net is especially successful with analysing high bandwidth connections with the results being similar to those of the physical network tests.

The performance measurement of a service provider network is an important activity. It is required for the smooth operation of the network as well as for reporting and planning. SANReN is a service provider tasked with serving the research and education network of South Africa. It currently has no structure or process for determining network performance metrics to measure the performance of its network. The objective of this study is to determine, through a process or structure, which metrics are best suited to the SANReN environment. This study is conducted in 3 phases in order to discover and verify the solution to this problem. The phases are "Contextualisation", "Design",and "Verification". The "Contextualisation" phase includes the literature review. This provides the context for the problem area but also serves as a search function for the solution. This study adopts the design science research paradigm which requires the creation of an artefact. The "Design" phase involves the creation of the conceptual network performance measurement model. This is the artefact and a generalised model for determining the network performance metrics for an NREN. To prove the utility of the model it is implemented in the SANReN environment. This is done in the "Verification" phase. The network performance measurement model proposes a process to determine network performance metrics. This process includes getting NREN requirements and goals, defining the NRENs network design goals through these requirements, define network performance metrics from these goals, evaluating the NRENs monitoring capability, and measuring what is possible. This model provides a starting point for NRENs to determine network performance metrics tailored to its environment. This is done in the SANReN environment as a proof of concept. The utility of the model is shown through the implementation in the SANReN environment thus it can be said that it is generic.The tools that monitor the performance of the SANReN network are used to retrieve network performance data from. Through understanding the requirements, determining network design goals and performance metrics, and determining the gap the retrieving of results took place. These results are analysed and finally aggregated to provide information that feeds into SANReN reporting and planning processes. A template is provided to do the aggregation of metric results. This template provides the structure to enable metrics results aggregation but leaves the categories or labels for the reporting and planning sections blank. These categories are specific to each NREN. At this point SANReN has the aggregated information to use for planning and reporting. The model is verified and thus the study’s main research objective is satisfied.

Många organisationer som anvander IT-system i sin verksamhet bedriver ocksa någon form av systemförvaltningsverksamhet. Någon eller några aktörer har till uppgift att kontinuerligt vidmakthålla och vidareutveckla organisationers verksamhet med hjälp av IT-system. Avhandlingen belyser hur detta arbete går till idag och hur det bör organiseras för att öka styrbarheten i systemförvaltningsverksamheter. Forskningsprocessen har haft en kvalitativ ansats med såväl induktiva som deduktiva inslag. Källstudier och intervjuer har genomförts for att kartlagga vilka aktiviteter som ingar i en systemförvaltningsverksamhet och hur den är organiserad. Dessutom har tre fallstudier genomförts med aktionsforskningsinslag i syfte att skapa effektiva förvaltningsobjekt som grund för organisering av systemförvaltningsverksamhet. Resultatet av arbetet är ett konceptuellt ramverk för att organisera systemförvaltningsverksamhet med hjalp av effektiva förvaltningsobjekt. Ramverket är uppbyggt kring fyra centrala begrepp; förvaltningsuppdrag, förvaltningsobjekt, förvaltningsorganisation och förvaltningsaktiviteter som alla ör relaterade till organiseringsbegreppet genom att de tre förstnämna utgör medel för att organisera systemförvaltningsverksamhet (aktiviteter). En delmängd av resultatet utgörs av en model för avgränsning och definition av förvaltningsobjekt. I avhandlingen ges ocksa förslag till referensdefinitioner på systemförvaltning och dess ingående aktiviteter; kunskapsstöd, ändringshantering, förvaltningsstyrning och daglig IT-drift och underhåll.

M.Comm. / This dissertation is devoted to an investigation into the network-management environment, with special emphasis on the security aspects and the provision of a reference framework when choosing a network-management product. The dissertation is aimed at those responsible for network-management and the selection of the various network-management products by providing a framework for evaluating network management products. The first four chapters provide the background to the reference framework. The following two chapters are devoted to those aspects to be taken into consideration when evaluating a network-management product. The consolidation and the case study in chapters seven and eight provide an abridged version of the framework and illustrate how the framework could be applied to a network-management product. Chapter one provides the background to the reference framework regarding networks and network-management. The concept of network-management is introduced, as well as the three forms of architectures that could be implemented, namely centralised, hierarchical and distributed architectures. A number of network-management functions have to be taken into consideration when evaluating a network-management package, namely configuration, asset, fault, performance, accounting and security management. These functions are also covered in chapter six. Chapter two provides the background to the security aspect of the reference framework. The three main topics covered in this respect are the definition of network-security, computer crime and specific elements of network-security. This chapter also provides a springboard for the evaluation of the network-management environment, as well as an idea of what issues and measures should be addressed and taken in order to prevent, or at least minimise, the effects of network-security breaches. Chapter three covers issues relating to network-security responsibilities, with special reference to the management side of network-management, including those issues that management should take into consideration when evaluating the network-management environment. Two methods that could be implemented include network-management policies and strategies. Network-security policies and strategies encompass those issues necessary for effective security within an organisation. This chapter, however, covers the more theoretical or higher-level goals or objectives of network-management. Chapter four relates to more of the day-to-day management issues of the network-security and the network-security management services and functions that should be considered. These include issues such as network-security services, managing network access, monitoring and controlling the network security system and the maintenance and modification of the said system. Network-management product considerations are discussed in chapter five, which chapter can be viewed as the business and practical side of the reference framework. The topics discussed here are more closely related to the business considerations when evaluating a networkmanagement package and the practical issues of network-management. Topics discussed in this chapter include security and network-management products, practical approaches to choosing network-management products, critical success factors of network-management and analysis of the cost component. In contrast to these issues, the reference framework expounded in chapter six concentrates on the technical and network-management functions. Chapter six constitutes the culmination of the present dissertation in the form of a reference framework, which is for the greater part formulated along the lines of the criteria given. This reference framework is aimed at those experts enlisted to evaluate and select networkmanagement products, specifically as far as their security-management features are concerned. The areas covered include the user framework, the product framework, networkfault management, network-performance management, network-accounting management, network configuration and change management, network-security management and conformance testing. The topics discussed are, however, by no means exclusive and there are a number of other issues that have not been addressed in this dissertation, but which, depending on the network environment, would have to be taken into consideration. Chapter seven is a consolidation of the reference framework given in chapter six, as well as of some of the main points and criteria that could be considered when performing a quick evaluation of a product. This chapter does not, however, make any pretence to being exhaustive, but merely serves to highlight a few crucial criteria. Chapter eight is devoted to a case study in terms of which the reference framework is applied to a network-management product. In conclusion, a summary of the dissertation is given in chapter nine.