Thesis (M.Eng.) - Carleton University, 1999. / Also available in electronic format on the Internet.

Thesis (M.S. in Computer Science)--Naval Postgraduate School, March 2005. / Thesis Advisor(s): Su Wen, Arijit Das. Includes bibliographical references (p. 149 p.). Also available online.

Thesis (M.S.)--University of Delaware, 2005. / Principal faculty adviser: Paul D. Amer, Dept. of Computer & Information Sciences. Includes bibliographical references.

This thesis presents a framework for investigating opportunistic routing in Delay Tolerant Mobile Ad hoc Networks (DTMANETs), and introduces the concept of an Opportunistic Confidence Index (OCI). The OCI enables multiple opportunistic routing protocols to be applied as an adaptive group to improve DTMANET routing reliability, performance, and efficiency. The DTMANET is a recently acknowledged networkarchitecture, which is designed to address the challenging and marginal environments created by adaptive, mobile, and unreliable network node presence. Because of its ad hoc and autonomic nature, routing in a DTMANET is a very challenging problem. The design of routing protocols in such environments, which ensure a high percentage delivery rate (reliability), achieve a reasonable delivery time (performance), and at the same time maintain an acceptable communication overhead (efficiency), is of fundamental consequence to the usefulness of DTMANETs. In recent years, a number of investigations into DTMANET routing have been conducted, resulting in the emergence of a class of routing known as opportunistic routing protocols. Current research into opportunistic routing has exposed opportunities for positive impacts on DTMANET routing. To date, most investigations have concentrated upon one or other of the quality metrics of reliability, performance, or efficiency, while some approaches have pursued a balance of these metrics through assumptions of a high level of global knowledge and/or uniform mobile device behaviours. No prior research that we are aware of has studied the connection between multiple opportunistic elements and their influences upon one another, and none has demonstrated the possibility of modelling and using multiple different opportunistic elements as an adaptive group to aid the routing process in a DTMANET. This thesis investigates OCI opportunities and their viability through the design of an extensible simulation environment, which makes use of methods and techniques such as abstract modelling, opportunistic element simplification and isolation, random attribute generation and assignment, localized knowledge sharing, automated scenario generation, intelligent weight assignment and/or opportunistic element permutation. These methods and techniques are incorporated at both data acquisition and analysis phases. Our results show a significant improvement in all three metric categories. In one of the most applicable scenarios tested, OCI yielded a 31.05% message delivery increase (reliability improvement), 22.18% message delivery time reduction (performance improvement), and 73.64% routing depth decrement (efficiency improvement). We are able to conclude that the OCI approach is feasible across a range of scenarios, and that the use of multiple opportunistic elements to aid decision-making processes in DTMANET environments has value.

Orientador: Edmundo Roberto Mauro Madeira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação / Made available in DSpace on 2018-08-21T07:23:57Z (GMT). No. of bitstreams: 1 Gomes_RafaelLopes_M.pdf: 1407268 bytes, checksum: c68d2355ef384cdcbcdb0658ddb32852 (MD5) Previous issue date: 2012 / Resumo: Ao longo dos anos a Internet vem se tornando o principal meio de comunicação, onde muitas empresas e organizações a usam como base para os seus serviços, sendo que na maioria dos casos, estas empresas têm vários provedores de Internet (Modelo Multi- Provedor). Entretanto, a Internet atual não provê garantias de Qualidade de Serviço (Quality of Service - QoS). Para contornar esse problema, as empresas realizam um Acordo de Nível de Serviços (Service Level Agreement - SLA). Dentro desse contexto, esta dissertação de mestrado tem por objetivo desenvolver uma arquitetura para negociação de redes virtualizadas na Internet do Futuro utilizando técnicas de classificação de tráfegos para decidir, a partir dos dados coletados e das políticas de SLA, por qual ISP (Internet Service Provider) enviar os dados de acordo com a classe que os dados se enquadram. Espera-se assim atender aos requisitos de QoS de cada classe de tráfego, e diminuir os custos da empresa. Para realizar a validação da arquitetura proposta, foram efetuados experimentos baseados no protocolo OpenFlow e no emulador Mininet. Os resultados mostraram a eficiência do modelo desenvolvido, bem como a capacidade do mesmo de cumprir os objetivos definidos / Abstract: Over the years the Internet has become the primary means of communication, where many companies and organizations use it as basis for their services, and in most cases, these companies have multiple Internet service providers (Multi-Provider Model). However, the current Internet does not guarantee Quality of Service (QoS), to circumvent this problem; the companies apply a Service Level Agreements (SLA). Within this context, this dissertation aims to develop architecture for traffic engineering based on traffic classification to decide, from the data collected and SLA policies, for which ISPs to send the data, according to the data class. It is expected to ensure QoS requirements of each traffic class, and reduce the costs of the company. To validate the proposed framework, experiments based on the OpenFlow protocol and on the Mininet emulator were performed. The results showed the efficiency of the framework, as well as its capacity to fulfill the desired requirements / Mestrado / Ciência da Computação / Mestre em Ciência da Computação

Please read the abstract in the section 00front of this document / Dissertation (MSc (Computer Science))--University of Pretoria, 2006. / Computer Science / unrestricted

Thesis (MSc.) -- University of Limpopo, 2017 / The notion of ubiquitous computing, Internet of things (IoT), big data, cloud computing and other emerging technologies has brougt forward the innovative paradigms and incredible developments in wireless communication technologies. The Wireless Mesh Networks (WMNs) technology has recently emerged as the promising high speed wireless technology to provide the last mile broadband Internet access and deliver flexible and integrated wireless communication solutions. The WMNs has the potential to enable people living in rural, peri-urban areas and small businesses to interconnect their networks and share the affordable Internet connectivity. The recent multimedia applications developed, such as voice over Internet protocol (VoIP), online gaming, cloud storage, instant messaging applications, and video sharing applications require high speed communication media and networks. These applications have witnessed enormous growth in the recent decade and continue to enhance communication amongst the users. Hence, the WMNs must have adequate capacity to support high bandwidth and real-time and multimedia applications. While the wireless communications networks are dependent on the radio frequency (RF) spectrum, the traditional wireless technologies utilise the RF spectrum bands inefficiently, resulting in sporadic and underutilisation of the RF spectrum. This inefficient usage of RF spectrum calls for novel techniques to leverage the available RF spectrum amongst different players in the wireless communication arena. There have been developments on integration of the WMNs with cognitive ratios to allow unlicensed users of RF spectrum to operate in the licensed portions of spectrum bands. This integration will provide the required bandwidth to support the required high speed broadband communication infrastructure. In this dissertation, we focus our research on the routing layer in a multi-hop wireless network environment. We addressed the routing challenges in both the WMNs and the cognitive radio based wireless mesh networks (CR-WMNs). The primary focus was to identify the routing protocols most suitable for the dynamic WMN environment. Once identified, the routing protocol was then ported to the CR-WMN environment to evaluate its performance given all the dynamics of cognitive radio environment. vi We further proposed the routing protocol called the extended weighted cumulative expected transmission time (xWCETT) routing protocol for the CR-WMNs. The design of our proposed xWCETT routing protocol is based on the multi-radio multi-channel architecture as it gives the base framework matching the cognitive radio environment. The xWCETT integrates features from the Ad-hoc On-demand Distance Vector (AODV) routing protocol and the weighted cumulative expected transmission time (WCETT) routing metric. The xWCETT was implemented using the Cognitive Radio Cognitive Network (CRCN) patch ported in network simulator (NS2) to incorporate the shared and dynamic spectrum access features. We compared the performance of our proposed xWCETT routing protocol with the AODV, dynamic source routing (DSR), the optimised link source routing (OLSR), Destination Sequences Distance Vector (DSDV), and the CRCN-WCETT routing protocols. The extensive simulation and numerical results show that the proposed xWCETT protocol obtained on average, around 10% better performance results in the CR-WNNs as compared to its routing counterparts. The comparative analysis and evaluation was performed in terms of the average end-to-end latency, throughput, jitter, packet delivery ratio, as well as the normalised routing load. The performance results obtained indicates that the proposed xWCETT routing protocol is a promising routing solution for dynamic CR-WMNs environment. / National Research Foundation (NRF)

The growing need for a trustworthy Future Internet demands evolutionary approaches unfettered by legacy constrains and concepts. The networking community is calling for new network architectural proposals that address the deficiencies identified in present network realizations, acknowledge the need for a trustworthy IT infrastructure, and satisfy the society's emerging and future requirements. Proposed architectures need to be founded on well-articulated design principles, account for network operational and management complexities, embrace technology and application heterogeneity, regulate network-inherent emergent behavior, and overcome shortcomings attributed to present network realizations. This dissertation presents our proposed clean-slate Concern-Oriented Reference Model (CORM) for architecting future computer networks. CORM stands as a guiding framework from which network architectures can be derived according to specific functional, contextual, and operational requirements or constraints. CORM represents a pioneering attempt within the network realm, and to our knowledge, CORM is the first reference model that is bio-inspired and derived in accordance with the Function-Behavior-Structure (FBS) engineering framework. CORM conceives a computer network as a software-dependent complex system whose design needs to be attempted in a concern-oriented bottom-up approach along two main dimensions: a vertical dimension addressing structure and configuration of network building blocks; and a horizontal dimension addressing communication and interactions among the previously formulated building blocks. For each network dimension, CORM factors the design space into function, structure, and behavior, applying to each the principle of separation of concerns for further systematic decomposition. In CORM, the network-building block is referred to as the Network Cell (NC), which represents CORM's first basic abstraction. An NC's structure and inherent behavior are bio-inspired, imitating a bacterium cell in a bacteria colony, thus it is capable of adaptation, self-organization and evolution. An NC's functional operation is defined by CORM second basic abstraction; the ACRF framework. The ACRF framework is a conceptual framework for network-concerns derived according to our interpretation of computer network requirement specifications. CORM networks are recursively synthesized in a bottom-up fashion out of CORM NCs. CORM addresses the multi-dimensionality of computer networks by modeling the network structure and behavior using a network structural template (NST), and an information flow model (IFM), respectively. Being developed according to a complex system paradigm, CORM refutes the long endorsed concept of layering, intrinsically accounts for emergent behavior, and ensures system integrity and stability. As a reference model, CORM is more typical of conventional engineering. Therefore it was validated using the FBS engineering framework. However, the behavior to be realized in CORM-based networks was substantiated and evaluated by deriving CellNet, our proposed CORM-based network architecture. CellNet-compliant protocols' behavioral adaptation and modification were illustrated and evaluated through simulation. CORM will have a profound impact on the operation and behavior of computer networks composing the Internet. By introducing awareness adaptability and evolvability as network intrinsic features, CORM-based Internet will proactively respond to changes in operational contexts, underlying technologies, and end user requirements. A major direction in CORM future work would be to detail the IFM component. / Ph. D.

Traditional routing protocols select paths based on static link weights and converge to new paths only when there is an outright reachability failure (such as a link or router failure). This design allows routing scale to hundreds of thousands of nodes, but it comes at the cost of functionality: routing provides only simple, single path connectivity. Networked applications in the wide-area, enterprise, and data center can all benefit from network protocols that allow traffic to be sent over multiple routes en route to a destination. This ability, also called multipath routing, has other significant benefits over single-path routing, such as more efficiently using network resources and recovering more quickly from network disruptions. This dissertation explores the design of an architecture for path selection in the network and proposes a "narrow waist" interface for networks to expose choice in routing traffic to end systems. Because most networks are also business entities, and are sensitive to the cost of routing traffic in their network, this dissertation also develops a framework for exposing paths based on their cost. For this purpose, this dissertation develops a cost model for routing traffic in a network. In particular, this dissertation presents the following contributions: * Design of path bits, a "narrow waist" for multipath routing. Our work ties a large number of multipath routing proposals by creating an interface (path bits) for decoupling the multipath routing protocols implemented by the network and end systems (or other network elements) making a choice for path selection. Path bits permit simple, scalable, and efficient implementations of multipath routing protocols in the network that still provide enough expressiveness for end systems to select alternate paths. We demonstrate that our interface is flexible and leads to efficient network implementations by building prototype implementations on different hardware and software platforms. * Design of path splicing, a multipath routing scheme. We develop, path splicing, a multipath routing technique, which uses random perturbations from the shortest path to create exponentially large number of paths with only a linear increase in state in a network. We also develop a simple interface to enable end systems to make path selection decisions. We present various deployment paths for implementing path splicing in both intradomain and interdomain routing on the Internet. * Design of low cost path-selection framework for a network. Network operators and end systems can have conflicting goals, where the network operators are concerned with saving cost and reducing traffic uncertainty; and end systems favor better performing paths. Exposing choice of routing in the network can thus, create a tension between the network operators and the end systems. We propose a path-selection framework where end systems make path selection decisions based on path performance and networks expose paths to end systems based on their cost to the network. This thesis presents a cost model for routing traffic in a network to enable network operators to reason about "what-if " scenarios and routing traffic on their network.

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