The current Internet presents a high barrier to entry for new service providers, due to its inability to accommodate new protocols and technologies, and lack of competition among the network providers. Recently, network virtualization has gained considerable attention as a possible solution, as it enables multiple networks to concurrently run over a shared substrate. It allows for deploying diverse network protocols and technologies customized for specific networked services and applications. Moreover, any party can take on the role of a network provider by simply offering his virtual network infrastructure to customers, increasing competition in the market. However, the first challenge in realizing a fair and competitive market in a virtual network environment is to have a service negotiation and contracting mechanism in place, that will allow (i) multiple infrastructure providers to participate in a fair and faithful competition, and (ii) a service provider to negotiate the price and quality of service with the providers. In this thesis, we present V-Mart, an open market model and enabling framework for automated service negotiation and contracting in a virtual network environment. To the infrastructure providers, V-Mart fosters an open and fair competition realized by a two stage auction. The V-Mart auction model ensures that bidders (infrastructure providers) bid truthfully, have the flexibility to apply diverse pricing policies, and still gain profit from hosting customers’ virtual resources. To the service providers, V-Mart offers virtual network partitioning algorithms that allow them to divide their virtual networks among competing infrastructure providers while minimizing the total cost. V-Mart offers two types of algorithms to suit different market scenarios. The algorithms not only consider virtual resource hosting price but also the service provider’s preference for resource co-location and the high cost of inter-provider communication. Through extensive simulation experiments we show the efficiency and effectiveness of the algorithms under various market conditions.

LACOME, the Large Collaborative Meeting Environment, is a collaboration system that allows multiple users to simultaneously publish their computer desktops (workspace) and/or windows on a large shared display via a network connection. Once published, windows or even full desktops can be moved, resized, and iconified; optionally, users can even interact with the content of other users. LACOME was originally designed and developed at The University of British Columbia; we extend the system to consider privacy and security concerns. We conducted a series of focus groups to obtain feedback on the initial design of the system. Based on our findings, we developed high level design requirements for future iterations of LACOME; these include the need for addressing privacy and security concerns when moving from the use of LACOME in a co-located setting to the overarching goal of its use in a mixed presence environment. We implemented new features that provide enhanced awareness of users’ shared workspaces and the interactions of others with them. We also developed an access control framework in the system that allows users to assign permissions on an ad-hoc basis. We undertook an initial evaluation of the LACOME system to evaluate the overall system and the changes that we made to it.

Network virtualization and overlay networks have emerged as powerful tools for improving the flexibility of the Internet. Overlays are used to provide a wide range of useful services in today's networking environment, and they are also viewed as important building blocks for an agile and evolvable future Internet. Regardless of the specific service it provides, an overlay needs assistance in several areas in order to perform properly throughout its existence. This dissertation focuses on the mechanisms underlying the provision of auxiliary support services that perform control and management functions for overlays, such as overlay assignment, resource allocation, overlay monitoring and diagnosis. The priorities and objectives in the design of such mechanisms depend on network conditions and the virtualization environment. We identify opportunities for improvements that can help provide auxiliary services more effectively at different overlay life stages and under varying assumptions. The contributions of this dissertation are the following: 1. An overlay assignment algorithm designed to improve an overlay's diagnosability, which is defined as its property to allow accurate and low-cost fault diagnosis. The main idea is to increase meaningful sharing between overlay links in a controlled manner in order to help localize faults correctly with less effort. 2. A novel definition of bandwidth allocation fairness in the presence of multiple resource sharing overlays, and a routing optimization technique to improve fairness and the satisfaction of overlays. Evaluation analyzes the characteristics of different fair allocation algorithms, and suggests that eliminating bottlenecks via custom routing can be an effective way to improve fairness. 3. An optimization solution to minimize the total cost of monitoring an overlay by determining the optimal mix of overlay and native links to monitor, and an analysis of the effect of topological properties on monitoring cost and the composition of the optimal mix of monitored links. We call our approach multi-layer monitoring and show that it is a flexible approach producing minimal-cost solutions with low errors. 4. A study of virtual network embedding in software defined networks (SDNs), identifying the challenges and opportunities for embedding in the SDN environment, and presenting two VN embedding techniques and their evaluation. One objective is to balance the stress on substrate components, and the other is to minimize the delays between VN controllers and switches. Each technique optimizes embedding for one objective while keeping the other within bounds.

Network virtualization is becoming a fundamental building block of future Internet architectures. By adding networking resources into the “cloud”, it is possible for users to rent virtual routers from the underlying network infrastructure, connect them with virtual channels to form a virtual network, and tailor the virtual network (e.g., load application-specific networking protocols, libraries and software stacks on to the virtual routers) to carry out a specific task. In addition, network virtualization technology allows such special-purpose virtual networks to co-exist on the same set of network infrastructure without interfering with each other. Although the underlying network resources needed to support virtualized networks are rapidly becoming available, constructing a virtual network from the ground up and using the network is a challenging and labor-intensive task, one best left to experts. To tackle this problem, we introduce the concept of a HyperNet, a pre-built, pre-configured network package that a user can easily deploy or access a virtual network to carry out a specific task (e.g., multicast video conferencing). HyperNets package together the network topology configuration, software, and network services needed to create and deploy a custom virtual network. Users download HyperNets from HyperNet repositories and then “run” them on virtualized network infrastructure much like users download and run virtual appliances on a virtual machine. To support the HyperNet abstraction, we created a Network Hypervisor service that provides a set of APIs that can be called to create a virtual network with certain characteristics. To evaluate the HyperNet architecture, we implemented several example Hyper-Nets and ran them on our prototype implementation of the Network Hypervisor. Our experiments show that the Hypervisor API can be used to compose almost any special-purpose network – networks capable of carrying out functions that the current Internet does not provide. Moreover, the design of our HyperNet architecture is highly extensible, enabling developers to write high-level libraries (using the Network Hypervisor APIs) to achieve complicated tasks.

The Virtual Network (VN) protocol is a communications protocol software compatible with the Space Plug-and-play Architecture (SPA). This Master Thesis defines a protocol that extends the Virtual Network protocol to cover communication over the Controller Area Network (CAN). The Virtual Network for the Controller Area Network (VN-CAN) is defined, modelled and verified using UPPAAL as well as implemented and tested while running on actual hardware. The VN-CAN protocol enables components on the CAN network to communicate with other components both inside and outside of the CAN network, which together with the modularity of both the protocol and the implementation enables application level software to be agnostic of their physical position in the network. The implementation enables components to automatically discover routes to other components on the VN network without the need for any prior knowledge about the network topology. A method for direct addressing, i.e. that two components on the CAN network can communicate directly without sending messages via a central router, has been added to the VN-CAN protocol in order to reduce traffic on the CAN network. UPPAAL modelling and verification of the VN-CAN protocol has been done to give a high level of confidence in the correctness of the protocol. Testing on actual hardware has shown that the protocol achieves the goals of address resolution, self addressing and transfer of VN messages over CAN.

As the "network of network", the Internet has been playing a central and crucial role in modern society, culture, knowledge, businesses and so on in a period of over two decades by supporting a wide variety of network technologies and applications. However, due to its popularity and multi-provider nature, the future development of the Internet is limited to simple incremental updates. To address this challenge, network virtualization has been propounded as a potential candidate to provide the essential basis for the future Internet architecture. Network virtualization is capable of providing an open and flexible networking environment in which service providers are allowed to dynamically compose multiple coexisting heterogeneous virtual networks on a shared substrate network. Such a flexible environment will foster the deployment of diversified services and applications. A major challenge in network virtualization area is the Virtual Network Embedding (VNE), which aims to statically or dynamically allocate virtual nodes and virtual links on substrate resources, physical nodes and paths. Making effective use of substrate resources requires high-efficient and survivable VNE techniques. The main contribution of this thesis is two high-performance p-Cycle-based survivable virtual network embedding approaches. These approaches take advantage of p-Cycle-based protection techniques that minimize the backup resources while providing a full VN protection scheme against link and node failures.

Virtualização permite o compartilhamento de uma rede física entre uma ou mais redes virtuais. O Problema de Mapeamento de Redes Virtuais é um dos principais desafios na virtualização de redes. Esse problema consiste em mapear uma rede virtual em uma rede física, respeitando restrições de capacidade. O presente trabalho mostra que encontrar uma solução factível para esse problema é NP-Difícil. Mesmo assim, muitas instâncias podem ser pode ser resolvidas na prática através da exploração de sua estrutura. Nós apresentamos um algoritmo de Branch & Price aplicado a instâncias de diferentes topologias e tamanhos. Os experimentos realizados sugerem que o algoritmo proposto é superior ao modelo de programação linear resolvido com CPLEX. / Virtualization allows one or more virtual networks to share physical infrastructures. The Virtual Network Embedding problem (VNEP) is one of the main challenges in the virtualization of physical networks. This problem consists in mapping a virtual network into a physical network while respecting capacity constraints. This work shows that finding a feasible solution for this problem is NP-Hard. However, many instances can be solved up to optimality in practice by exploiting the problem structure. We present a Branch & Price algorithm applied to instances of different topologies and sizes. The experimental results suggest that the proposed algorithm is superior to the Integer Linear Programming model solved by CPLEX.

A virtualização de redes é um mecanismo que permite a coexistência de múltiplas redes virtuais sobre um mesmo substrato físico. Um dos desafios de pesquisa abordados na literatura é o mapeamento eficiente de recursos virtuais em infraestruturas físicas. Embora o referido desafio tenha recebido considerável atenção, as abordagens que constituem o estado-da-arte apresentam alta taxa de rejeição, i.e., a proporção de solicitações de redes virtuais negadas em relação ao total de solicitações efetuadas ao substrato é elevada. Nesta dissertação, caracteriza-se, inicialmente, a relação entre a qualidade dos mapeamentos de redes virtuais e as estruturas topológicas dos substratos subjacentes. Avalia-se as soluções exatas de um modelo de mapeamento online sob diferentes classes de topologias de rede. A partir do entendimento dos fatores topológicos que influenciam diretamente o processo de mapeamento de redes virtuais, propõe-se uma estratégia para planejar a expansão de redes de provedores de infraestrutura de forma a reduzir consistentemente a taxa de rejeição de requisições de redes virtuais e melhor aproveitar os recursos ociosos da mesma. Os resultados obtidos evidenciam que grande parte das rejeições de redes virtuais ocorre em situações em que há grande disponibilidade de recursos, mas alguns poucos já saturados acabam inviabilizando, em função de características de conectividade do substrato, o atendimento de novas requisições. Ademais, os resultados obtidos utilizando a estratégia proposta evidenciam que o fortalecimento de partes-chave da infraestrutura levam a uma ocupação muito mais satisfatória. Uma expansão de 10% a 20% dos recursos da infraestrutura contribui para um aumento sustentado de até 30% no número de redes virtuais aceitas e de até 45% no aproveitamento dos recursos em comparação com a rede original. / Network virtualization is a mechanism that allows the coexistence of multiple virtual networks on top of a single physical substrate. One of the research challenges addressed recently in the literature is the efficient mapping of virtual resources on physical infrastructures. Although this challenge has received considerable attention, state-of-the-art approaches present, in general, a high rejection rate, i.e., the ratio between the number of denied virtual network requests and the total amount of requests is considerably high. In this thesis, we characterize the relationship between the quality of virtual network mappings and the topological structures of the underlying substrates. Exact solutions of an online embedding model are evaluated under different classes of network topologies. From the understanding of the topological factors that directly influence the virtual network embedding process, we propose an expansion strategy of physical infrastructure in order to suggest adjustments that lead to higher virtual network acceptance and, in consequence, to improved physical resource utilization. The obtained results demonstrate that most of rejections occur in situations in which a significant amount of resource is available, but a few saturated devices and links, depending on connectivity features of the physical substrate, hinder the acceptance of new requests. Moreover, the obtained results using the proposed strategy evidence that an expansion of 10% to 20% of the infrastructure resources leads to a sustained increase of up to 30% in the number of accepted virtual networks and of up to 45% in resource usage compared to the original network.

Virtualização permite o compartilhamento de uma rede física entre uma ou mais redes virtuais. O Problema de Mapeamento de Redes Virtuais é um dos principais desafios na virtualização de redes. Esse problema consiste em mapear uma rede virtual em uma rede física, respeitando restrições de capacidade. O presente trabalho mostra que encontrar uma solução factível para esse problema é NP-Difícil. Mesmo assim, muitas instâncias podem ser pode ser resolvidas na prática através da exploração de sua estrutura. Nós apresentamos um algoritmo de Branch & Price aplicado a instâncias de diferentes topologias e tamanhos. Os experimentos realizados sugerem que o algoritmo proposto é superior ao modelo de programação linear resolvido com CPLEX. / Virtualization allows one or more virtual networks to share physical infrastructures. The Virtual Network Embedding problem (VNEP) is one of the main challenges in the virtualization of physical networks. This problem consists in mapping a virtual network into a physical network while respecting capacity constraints. This work shows that finding a feasible solution for this problem is NP-Hard. However, many instances can be solved up to optimality in practice by exploiting the problem structure. We present a Branch & Price algorithm applied to instances of different topologies and sizes. The experimental results suggest that the proposed algorithm is superior to the Integer Linear Programming model solved by CPLEX.

Virtualização permite o compartilhamento de uma rede física entre uma ou mais redes virtuais. O Problema de Mapeamento de Redes Virtuais é um dos principais desafios na virtualização de redes. Esse problema consiste em mapear uma rede virtual em uma rede física, respeitando restrições de capacidade. O presente trabalho mostra que encontrar uma solução factível para esse problema é NP-Difícil. Mesmo assim, muitas instâncias podem ser pode ser resolvidas na prática através da exploração de sua estrutura. Nós apresentamos um algoritmo de Branch & Price aplicado a instâncias de diferentes topologias e tamanhos. Os experimentos realizados sugerem que o algoritmo proposto é superior ao modelo de programação linear resolvido com CPLEX. / Virtualization allows one or more virtual networks to share physical infrastructures. The Virtual Network Embedding problem (VNEP) is one of the main challenges in the virtualization of physical networks. This problem consists in mapping a virtual network into a physical network while respecting capacity constraints. This work shows that finding a feasible solution for this problem is NP-Hard. However, many instances can be solved up to optimality in practice by exploiting the problem structure. We present a Branch & Price algorithm applied to instances of different topologies and sizes. The experimental results suggest that the proposed algorithm is superior to the Integer Linear Programming model solved by CPLEX.