Virtual Networks

Assigning the resources of a virtual network to the components of a physical network, called Virtual Network Mapping, plays a central role in network virtualization. Existing approaches use classical heuristics like simulated annealing or attempt a two stage solution by solving the node mapping in a first stage and doing the link mapping in a second stage.

Leadership has been defined in various ways with some scholars strongly suggesting that it is a calling or something driven by a trait [1], which is expressed through personal values, integrity and certain qualities [2-5]. Leadership in virtual networks, however, is more of an earned recognition. This article argues that leadership in these virtual networks is about character-building. We approach this study by reviewing the literature around character-building, which we then model as discretionary effort (DE), a construct of expectancy, instrumentality, valence and self-affirmation, which explains the extra effort spent beyond the work-role requirement. Additionally, we review the coaching literature, which, when applied to our DE model, provides a path along which DE can be encouraged. We investigate whether work leverage earned through DE is shaped by process-oriented factors such as 'experience'. 'Gender' and 'profession' are also investigated as other added influencer factors. The study is based on professional networks with a data sample of 1548 managers and specialists in different sectors. Results reveal that process-oriented variables, such as 'experience', significantly explain the variability in the DE build-up process. DE levels are also observed to be different between sectors. 'Gender' did not have any effect on the results, either at unit or inter-unit relations, in clusters of employees who are either virtually-located or co-located.

The paper assesses the market conditions and dynamics, the architectures and the different approaches for deployment of 3G Mobile Virtual Network Operators (MVNOs), in an attempt to address specific advantages and pitfalls. Following the definition of appropriate service sets and tariff structures, and taking into account demand scenarios, a techno-economic model has been developed, in order to compute key economic indicators. The paper presents techno-economic results of specific business cases and deployment alternatives for an average "large" European country and a smaller, Nordic-type country. Fixed and variable costs have been identified and the business case shows how different service sets lead to different costs. Different MVNO business profiles have been investigated. Profitability for all scenarios and business profiles has been calculated, presented and discussed. Major opportunities and threats, as well as critical parameters and uncertainties have been identified through sensitivity analysis.

The present paper demonstrates that virtual science and technology parks (V-STPs) and real-estate-based science and technology parks (RE-STPs) should not be alternative or opposed institutions but rather complementary solutions, since these two concepts contain in themselves strong mutual synergies. Integrated V-STPs and RE-STPs are the successful real science and technology parks (STPs) of the future.

RFnest TM is an FPGA based network channel emulator that allows all of the channels for a full network of radio nodes to be emulated in real time, with all communication experiencing a realistic channel impulse response and correct interference. RFnest TM is the first network emulator that allows virtual simulated nodes and real RF nodes to interact and have a shared wireless feeling. In other words, the real RF nodes in RFnest TM receive the signals sent by the virtual simulated nodes on their real radios and vice versa. This capability allows both high fidelity and scalable network simulation and emulation within the same controlled and repeatable environment. This allows RFnest TM to be used for protocol testing, replaying field tests, and model validation. RFnest TM has a modular design with three main components: 1) FPGA based emulation hardware with RF front ends to allow nodes with real radios to send their RF signal over an emulated channel without any modification to the radio, 2) modeling of time-varying channel impulse responses within the emulation hardware, with channel properties based on mobility defined with a scripted or interactive GUI environment, and 3) integration with network emulators and monitoring functionality allowing the user to instantiate, manage, and monitor real and virtual network nodes within the scenario.

Resumo Network Virtualization is claimed to be a key component of the Future Internet by enabling the coexistence ofheterogeneous (virtual) networks on the same physical infrastructure [1], providing the dynamic creation and support of different networks with different paradigms and mechanisms. In order for virtualization to be used in a network operator's infrastructure, its impact on the network traffic must be studied. In this paper, we perform an analysis of the impact of network virtualization on two types of traffic, TCP and ...

Purpose -Social websites have become a major medium for social interaction. From Facebook to MySpace to emergent sites like Twitter, social websites are increasing exponentially in user numbers and unique visits every day. How do these websites encourage sociability? What features or design practices enable users to socialize with other users? The purpose of this paper is to explore sociability on the social web and details how different social websites encourage their users to interact. Design/methodology/approach -Four social websites (Facebook, MySpace, LinkedIn and Twitter) were examined from a user study perspective. After thoroughly participating on the websites, a series of observations were recorded from each experience. These experiences were then compared to understand the different approaches of each website. Findings -Social websites use a number of different approaches to encourage sociability amongst their users. Facebook promotes privacy and representing ''real world'' networks in web environment, while MySpace promotes publicity and representing both real world and virtual networks in a web environment. Niche websites like LinkedIn and Twitter focus on more specific aspects of community and technology, respectively. Originality/value -A comparison of different models of sociability does not yet exist. This study focuses specifically on what makes social websites ''social.''

Entrepreneurship is at the heart of sustainable, organic growth for most developed, as well as transitioning and developing economies and incubators have often served as catalysts and even accelerators of entrepreneurial clusters formation and growth. Our premise is that this may be more so in less developed economies where incubators can help bridge knowledge, digital, socio-political and even cultural divides and help increase the availability, awareness, accessibility and affordability of financial, human, intellectual, and ...

The GridNets conference series is an annual international meeting which provides a focused and highly interactive forum where researchers and technologists have the opportunity to present and discuss leading research, developments, and future directions in the grid networking area. The objective of this event is to serve as both the premier conference presenting the best grid networking research and a forum where new concepts can be introduced and explored.

Network Functions Virtualization (NFV) has been
revolutionizing and improving the way networking services are
deployed but also requires the dynamic scaling of resources
during the lifecycle management of Virtual Network Functions
(VNFs) with increasing service demand. We propose an Integer
Linear Programming (ILP) approach and a Greedy heuristic to
address this NP-Hard scaling problem. Both horizontal (scale
out/in) and vertical (scale up/down) scaling are considered and
the scalability of the ILP is addressed by reducing the number
of candidate hosts in the search space. Extensive simulations
evaluate the performance of the algorithms in successful scalings
and VNF migrations and highlight the importance of using the
algorithms to tidy up the infrastructure to accept more users. The
results show that the ILP can outperform the Greedy heuristic
if appropriate actions are selected.

The life of followers of African Prophetic Churches is divided between an intense, completely localized community life and exceptionally large mass gatherings linked to evangelist campaigns or to pilgrimages. Through the trajectories of immigration that these Churches accompany and the missionary functions exercised by their pastors and prophets, who are constantly crossing borders, the lives of their followers are increasingly

Entrepreneurship is at the heart of sustainable, organic growth for most developed, as well as transitioning and developing economies and incubators have often served as catalysts and even accelerators of entrepreneurial clusters formation and growth.

The travel and tourism sector has emerged as one of the most important sectors for developing as well as developed countries. Tourism incorporates many of the features of the information society such as globalization, mobility and information richness. People from all nations, social rank, and professions are potential tourists. Tourism links a worldwide supplier community with consumers, equally distributed worldwide.

Despite its many foreseen benefits, the main barrier to adoption of cloud computing remains security. Vulnerabilities introduced by virtualization of computing resources, and unclear effectiveness of traditional security architectures in fully virtualized networks raise many security challenges . The most critical issue remains resource sharing in a multitenant environment, which creates new attack vectors. The question is thus how to guarantee strong resource isolation, both on the computing and networking side. System and network complexity make manual security maintenance impossible by human administrators. Computing and networking isolation over virtualized environments should thus be achieved and automated.

A data center is an infrastructure that supports Internet service. Cloud computing is rapidly changing the face of the Internet service infrastructure, enabling even small organizations to quickly build Web and mobile applications for millions of users by taking advantage of the scale and flexibility of shared physical infrastructures provided by cloud computing. In this scenario, multiple tenants save their data and applications in shared data
centers, blurring the network boundaries between each tenant in the cloud. In addition, different tenants have different security requirements, while different security policies are necessary for different tenants. Network virtualization is used to meet a diverse set of tenant-specific requirements with the underlying physical network, enabling multi-tenant datacenters to automatically address a large and diverse set of tenants requirements. In this
paper, we propose the system implementation of vCNSMS, a collaborative network security prototype system used in a multi-tenant data center. We demonstrate vCNSMS with a centralized collaborative scheme and deep packet inspection with an open source UTM system. A security level based protection policy is proposed for simplifying the security rule management for vCNSMS. Different security levels have different packet inspection schemes and are enforced with different security plugins. A smart packet verdict scheme is also integrated into vCNSMS for intelligence flow processing to protect from possible network attacks inside a data center network.

Instagram has become the bridge between consumers who share moments from their lives and companies that share their products and services with the users. Instagram stands out from the other social media networks thanks to user-friendly toolkit that provides photo editing, video sharing and Instagram stories. At the same time, there are several "celebrities" who share their personal and professional life with the "ordinary" users. This conceptual model research investigates the impact of Instagram on user's attitude. Data were collected from young Instagram users in order to measure if there is a relationship between specific factors of Instagram and user attitude through Structural Equation Modeling (SEM). The main purpose of the research is to find out if there is a positive relationship among the following Instagram factors and user attitude. In this research, will be analyzed the consumer behavior in social media and particularly on Instagram. As a first stage of our research we are going to develop the theoretical study for Instagram users (n=188) at the age of 18-34, investigating the behavior of use Instagram which is determined by social presence. This study presents a theoretical conceptual model based on the theory of social presence, perceived pleasure, perceived usefulness and perceived value on Instagram and the potential connection of those factors to the user attitude.

It is now possible to allow VMs hosting HPC applications to seamlessly bridge distributed cloud resources and tightly-coupled supercomputing and cluster resources. However, to achieve the application performance that the tightly-coupled resources are capable of, it is important that the overlay network not introduce significant overhead relative to the native hardware, which is not the case for current user-level tools, including our own existing VNET/U system. In response, we describe the design, implementation, and evaluation of a layer 2 virtual networking system that has negligible latency and bandwidth overheads in 1-10 Gbps networks. Our system, VNET/P, is directly embedded into our publicly available Palacios virtual machine monitor (VMM). VNET/P achieves native performance on 1 Gbps Ethernet networks and very high performance on 10 Gbps Ethernet networks and InfiniBand. The NAS benchmarks generally achieve over 95% of their native performance on both 1 and 10 Gbps. These results suggest it is feasible to extend a software-based overlay network designed for computing at wide-area scales into tightly-coupled environments.

Resumo Network Virtualization is claimed to be a key component of the Future Internet by enabling the coexistence ofheterogeneous (virtual) networks on the same physical infrastructure [1], providing the dynamic creation and support of different networks with different paradigms and mechanisms. In order for virtualization to be used in a network operator's infrastructure, its impact on the network traffic must be studied.

This paper presents the design, development and evaluation of Virtual Showroom that focused on interactivity in by manipulating the capabilities of VRML technology. The Virtual Showroom provides virtual furniture that can be viewed, navigated and interacted by the user. Besides that, users are given an option to create the interior design of their own room by dragging virtual furniture provided. Development process involves specific process such as planning, object modeling, navigation, web page integration and evaluation. Evaluation has been done using questionnaire by 30 participants that concentrate on six criteria such as ease of navigation, effectiveness of the interface and user acceptance. Result shows that all of the participants give positive feedback regarding the evaluated criteria and it proves that the objectives of the project have been successfully achieved and able to satisfy both the developer and customers. The development of Virtual Showroom showed that it is possible to have a virtual furniture shop that provided full control for the user while navigating. This can gave a new perspective for the user while do online shopping. The next step is to enhance the application by integrating avatar in order to help first time users in navigating the virtual showroom.

Mobile virtual network operators (MVNOs) do not hold spectrum licenses and own little or no network infrastructure. Rather, they resell mobile services by purchasing airtime at wholesale rates from mobile network operators (MNOs). Unlike ordinary resellers, MVNOs rely on brand appeal and reputation acquired in other businesses to sell mobile services (often bundled with other products). Significant worldwide growth in voluntary MNO-MVNO partnerships, without intervention from public policies that mandate MVNO access to MNO networks, raises many interesting issues. Since MNOs that sell wholesale services to MVNOs potentially forfeit sales in downstream retail markets, voluntary relationships are plausible only if MVNOs add value by widening and/or deepening MNO-served markets. This paper provides sufficient conditions for profit-maximizing MNOs and MVNOs to form voluntary strategic partnerships based on resale, product differentiation, and rebranding. The two key factors are (1) value of the MVNO's brand reputation and (2) wholesale discount at which the MNO offers service to the MVNO. -1325. We gratefully acknowledge the comments and suggestions of the editor and three anonymous referees for helping to improve the paper in a number of directions. All remaining errors are our responsibility.

Network virtualization is receiving immense attention in the research community all over the world. There is no doubt that it will play a significant role in shaping the way we do networking in the future. There have been different approaches to virtualize different aspects of the network: some are focusing on resource virtualization like node, server and router virtualization; while others are focusing on building a framework to set up virtual networks on the fly based on different virtual resources. Nevertheless, one very important piece of the puzzle is still missing, that is “Wireless Virtualization”. The virtualization of the wireless medium has not yet received the appropriate attention it is entitled to, and there have only been some early attempts in this field. In this paper a general framework for virtualizing the wireless medium is proposed and investigated. This framework focuses on virtualizing mobile communication systems so that multiple operators can share the same physical resources while being able to stay isolated from each other. We mainly focus on the Long Term Evolution (LTE) but the framework can also be generalized to fit any other wireless system. The goal of the paper is to exploit the advantages that can be obtained from virtualizing the LTE system, more specifically virtualizing the air interface (i.e. spectrum sharing). Two different possible gain areas are explored: spectrum multiplexing and multi-user diversity.

Multi-Modal freight models are traditionally built following the well known "fours steps model" in which generation, distribution, modal-split and assignment are seen as separated modules. An alternative approach, implemented in some softwares, is to represent the multi-modal network by means of a mono-modal one, representing each particular transport operation (loading or unloading operation, transhipments, ...) by a dedicated "virtual link". This approach is proven to give interesting results, but as the drawback to generate much larger networks as their geographic representation.

The evolution of organizations that work in multinational environments has considerably altered their production strategies. One of the consequences has been the appearance of Global Manufacturing Virtual Networks (GMVNs), which include all kinds of enterprises and production centres and establish a new type of horizontal collaboration and relations between independent companies and even competitors who establish occasional collaborations on projects they could not take on individually. This paper analyses the causes behind the formation of such networks, their strategy, structure, dynamics and evolution, taking into account areas such as strategic intercompany alliances, synchronization of their value and supply chains, their information systems, the cultural aspects of the organizations in question and, finally, their convergence with another of the more relevant future trends in production: mass customization. The proposed model shall be applied to the aeronautical industry which is one of the industries which has developed the GMVN concept. The case study of the engine manufacturer Rolls Royce will provide a better understanding of the evolution of its strategic positioning, as well as the dynamic and fluent nature of its virtual relations. This will demonstrate its effectiveness by clarifying and putting these organizations in perspective and analyzing their evolution over the next few years.

Like most developing nations, Malaysia has always been concerned about bringing its large rural community -half the population -into the mainstream of development. The government has identified Information and Communication Technology (ICT) as key to achieving developed nation status by the year 2020 and considerable efforts in the field of education has been conducted. Rural schools, which hold the potential to yield IT competent students, are beneficiary to innovations implemented to incrementally encroach them into the technological environment. This paper will elucidate the educational broadcasting efforts to reach the rural areas and the Mobile Internet Unit (MIU), a development project on computer-mediated education for school teachers and students, as well as people in rural and urban marginalised communities. Most recently the SchoolNet endeavour now links 5 million school children in Malaysia via the Private Virtual Network.

In this paper we show how to establish a reliable and efficient high level communication system in a randomly deployed network of sensors equipped with directional antennas. This high level communication system enables the programming of the sensor network using high level communication functionalities without the burden of taking care of their physical capacities (low range, unidirectional links, single frequency, presence of collisions, etc.). The high level communication functionalities we offer include point-topoint communication, point-to-area communication, and one-to-all communication. The basic idea to implement this system is to simulate a virtual network that emerges from the ad-hoc network using self-organization, self-discovery and collaborative methods. We also analyse the efficiency, scalability and robustness of the proposed protocols.

This paper will review effectiveness of the network approach to technology transfer. It will consider the current state-of-the-art, and look specifically at the results and status of the latest development of the IRC technology transnational transfer network supported by the European Commission. It will also draw from the practical experiences of Japan to stimulate innovation among SME's; the experience of other informal networks of technology transfer professionals (e.g. networks of university technology transfer offices, networks of TT brokers); and commercial technology transfer companies. In Europe the IRC Network currently consists of 68 offices covering 31 countries -including the 15 components of the European Union plus 16 other European states. This network was started in 1995 and it is a distinct case of an operating innovation virtual network covering a multi cultural area. How such a network was set up with a top down approach will be discussed as well as the outcome and future of the network in view of a recent review study. Of outmost importance is its focus on SME's as part of the, up to now, successful policy towards the promotion of cooperative innovation in the SME environment. Its offer focus model will be also analysed and consideration given as to whether this focus versus a demand focus model can be sustained. The influences that the different socio economic environments across Europe have been playing in the network performance will also be discussed.

Based on research carried out among Gottscheers (Gottschee Germans) living in the USA, Canada, Austria and Germany, the article presents the social and symbolic meaning of the places the Gottscheers identify with and that influence their life as emigrants. These places are: the old country – Gottschee (the Kočevska region) and the places that are important for the (re)production of their traditions in their new countries. The article also describes the meaning of rituals, including pilgrimages to the old homeland and meetings in their new countries for strengthening their feeling of belonging to a group within the country of residence, and for the transnational connections between the Gottscheers from the mentioned countries and with the old homeland. The article concludes that the survival of the diaspora depends largely on its ability to maintain its culture and traditions through ritual practices at various locations outside the home country.

Trusted collaborative systems require peers to be able to communicate over private, authenticated end-to-end channels. Network-layer approaches such as Virtual Private Networks (VPNs) exist, but require considerable setup and management which hinder the establishment of ad-hoc collaborative environments: trust needs to be established, cryptographic keys need to be exchanged, and private network tunnels need to be created and maintained among end users. In this paper, we propose a novel system architecture which leverages existing social infrastructures to enable ad-hoc VPNs which are self-configuring, self-managing, yet maintain security amongst trusted and untrusted third parties. The key principles of our approach are: (1) self-configuring virtual network overlays enable seamless bi-directional IP-layer connectivity to socially connected parties; (2) online social networking relationships facilitate the establishment of trust relationships among peers; and (3) both centralized and decentralized databases of social network relationships can be securely integrated into existing public-key cryptography (PKI) implementations to authenticate and encrypt end-to-end traffic flows. The main contribution of this paper is a new peer-to-peer overlay architecture that securely and autonomously creates VPN tunnels connecting social peers, where online identities and social networking relationships may be obtained from centralized infrastructures, or managed in a decentralized fashion by the peers themselves. This paper also reports on the design and performance of a prototype implementation that embodies the SocialVPN architecture. The SocialVPN router builds upon IP-over-P2P (IPOP) virtual networks and a PKI-based tunneling infrastructure, which integrates with both centralized and decentralized social networking systems including Facebook, the Drupal opensource content management system, and emailing systems with PGP support. We demonstrate our prototype's ability to support existing, unmodified TCP/IP applications while transparently dealing with user connectivity behind Network Address Translators (NATs). We also present qualitative and quantitative analyses of functionality and performance based on wide-area network experiments using PlanetLab and Amazon EC2.

Bowman is an extensible platform for active networking: it layers active-networking functionality in user-space software over variants of the System V UNIX operating system. The packet processing path implemented in Bowman incorporates an efficient and flexible packet classification algorithm, supports multi-threaded per-flow processing, and utilizes real-time processor schedulingto achieve deterministic performance in userspace. In this paper we describe the design and implementation of Bowman; discuss the support that Bowman provides for implementing execution environments for active networking; discuss the network-level architecture of Bowman that can be used to implement virtual networks; and present performance data. Bowman is able to sustain 100 Mbps throughput while forwarding IP packets over fast Ethernets.

Mobile ad hoc networking has been a hot research topic for a decade or so, and many paradigms have been making use of it. One of these paradigms is the Personal Networks (PN). It is an emerging concept where the user's personal devices form a virtual network which is secure and private, and reacts to changing environment and context intelligently. A fundamental property of the PN is that personal devices form private multi-hop clusters in an ad hoc manner whenever they come across each other. To this end, this paper presents a pair-wise key based scheme for forming secured private clusters in mobile ad-hoc networks. The solution tackles the problem of node authentication combined with traffic encryption in relatively small ad-hoc networks using proactive neighbour discovery and authentication. Additionally, the paper proves the feasibility of this solution by means of prototyping and experimental performance analysis.

Active networking is a powerful technology to insert new functionality into the networking. In this paper we look at how active networking technology can be used to customize network services. We observe that users often want slightly different versions of network services such as multicast and network quality of service. We propose to implement these services as a base service that provides the basic service functionality and a customization code modules that allows users to customize the service. The customization module uses a service-specific API to modify service behavior. We compare this architecture with the traditional active networking architecture based on execution environments and active applications. We also present several examples of customizable network services.

Due to the existence of multiple stakeholders with conflicting goals and policies, alterations to the existing Internet are now limited to simple incremental updates; deployment of any new, radically different technology is next to impossible. To fend off this ossification once and for all, network virtualization has been propounded as a diversifying attribute of the future inter-networking paradigm. By allowing multiple heterogeneous network architectures to cohabit on a shared physical substrate, network virtualization provides flexibility, promotes diversity, and promises security and increased manageability. In this paper, we present a network virtualization model with a set of quintessential design goals, survey the past and the state-of-the-art of network virtualization, and discuss the future challenges that must be addressed to realize a viable network virtualization model.

In this paper we are concerned with providing support for business activities in moving from value chains to value networks. We describe a fully distributed P2P architecture which reflects the dynamics of business processes that are not governed by a single organisation. The temporary virtual networks of long-term business transactions are used as the building block of the overall scale-free business network. The design is based on dynamically formed permanent clusters resulting in a topology that is highly resilient to failures (and attacks) and is capable of reconfiguring itself to adapt to changes in business models and respond to global failures of conceptual hubs. This fosters an environment where business communities can evolve to meet emerging business opportunities and achieve sustainable growth within a digital ecosystem.

We present a Peer-to-Peer network design which aims to support business activities conducted through a network of collaborations that generate value in different, mutually beneficial, ways for the participating organisa-tions. The temporary virtual networks ...

The present work introduces a methodology to obtain a discrete time state space representation of an electrical network using the nodal [G] matrix of the Electromagnetic Transients Program (EMTP) solution. This is the first time the connection between the EMTP nodal analysis solution and a corresponding state-space formulation is presented. Compared to conventional state space solutions, the nodal EMTP solution is computationally much more efficient. Compared to the phasor solutions used in transient stability analysis, the proposed approach captures a much wider range of eigenvalues and system operating states. A fundamental advantage of extracting the system eigenvalues directly from the EMTP solution is the ability of the EMTP to follow the characteristics of nonlinearities. The system's trajectory can be accurately traced and the calculated eigenvalues and eigenvectors correctly represent the system's instantaneous dynamics. In addition, the algorithm can be used as a tool to identify network partitioning subsystems suitable for real-time hybrid power system simulator environments, including the implementation of multi-time scale solutions. The proposed technique can be implemented as an extension to any EMTPbased simulator. Within our UBC research group, it is aimed at extending the capabilities of our real-time PC-cluster Object Virtual Network Integrator (OVNI) simulator.

I hope that after reading this issue the readers will either have a good understanding about the MVNO concept or get confused and provoked enough to start doing research on MVNO ... Enjoy your reading. 3 The Mobile Business Landscape-an Analytical Approach A business model may be defined as an individual company's set of choices about what to do and how to do it. In this section, some frameworks used to evaluate sustainability of MVNO business models are described. Keywords are network externalities, complementary services / products and value configuration. Many various environmental aspects may be of great importance. Focus of approach is business strategy, industrial organization and competitive power, but other aspects such as underlying needs of the customer and government policy (regulation) may be crucial.