Networked Virtual Environments Research Articles

Workload-Aware Credit Scheduler for Improving Network I/O Performance in Virtualization Environment

Single-root I/O virtualization (SR-IOV) has become the de facto standard of network virtualization in cloud infrastructure. Owing to the high interrupt frequency and heavy cost per interrupt in high-speed network virtualization, the performance of network virtualization is closely correlated to the computing resource allocation policy in Virtual Machine Manager (VMM). Therefore, more sophisticated methods are needed to process irregularity and the high frequency of network interrupts in high-speed network virtualization environment. However, the I/O-intensive and CPU-intensive applications in virtual machines are treated in the same manner since application attributes are transparent to the scheduler in hypervisor, and this unawareness of workload makes virtual systems unable to take full advantage of high performance networks. In this paper, we discuss the SR-IOV networking solution and show by experiment that the current credit scheduler in Xen does not utilize high performance networks efficiently. Hence we propose a novel workload-aware scheduling model with two optimizations to eliminate the bottleneck caused by scheduler. In this model, guest domains are divided into I/O-intensive domains and CPU-intensive domains according to their monitored behaviour. I/O-intensive domains can obtain extra credits that CPU-intensive domains are willing to share. In addition, the total number of credits available is adjusted to accelerate the I/O responsiveness. Our experimental evaluations show that the new scheduling models improve bandwidth and reduce response time, by keeping the fairness between I/O-intensive and CPU-intensive domains. This enables virtualization infrastructure to provide cloud computing services more efficiently and predictably.

Monitoring Virtual Nodes using mashups

The use of virtualization technologies is one of major trends in computer networks. Up to now, most of monitoring tasks on Virtual Nodes, made up of several system virtualization environments and network virtualization environments, require manual intervention via non-standardized interfaces. Although monitoring based on proprietary command lines and graphical user interfaces may be enough for homogeneous Virtual Nodes, it is certainly not suitable for monitoring, in an integrated way, Virtual Nodes in which, the aforementioned environments use heterogeneous virtualization technologies, both in networks and systems. In this paper, we demonstrate that the mashup technology can be used to carry out the integrated monitoring of heterogeneous Virtual Nodes. In this sense, we present a mashup-based architecture targeted to monitor such type of Virtual Nodes, we introduce a reference implementation of the mashup-based architecture, and we develop on it, three monitoring mashups. The quantitative assessment of these mashups corroborates that they generate low traffic and have short response time. Furthermore, their qualitative assessment reveals that it is feasible to provide flexible and extensible mashups for monitoring Virtual Nodes.

Resource discovery and allocation for federated virtualized infrastructures

The European Union Project Networking innovations Over Virtualized Infrastructures (NOVI) set out to design and implement a modular data, control and management plane federation architecture, leading to an integrated experimental prototype mounted on interconnected European Future Internet testbeds. In this paper we present the components of this architecture, responsible for resource discovery and mapping of virtual topologies over a federated multi-domain network virtualization environment. We subsequently introduce a method for the efficient mapping of user requests for virtual networks onto a substrate infrastructure, adopting a semantic-based approach to address the problem. The efficiency of the proposed scheme is evaluated via simulation and critically compared against common non-semantic-based solutions.

A Study on Credit Appraisal System of C2C E-Commerce <br/>—Based on the Analysis of Taobao

In the virtual network environment, the C2C e-commerce has some problems in product quality, service, credit speculation. At present the credit appraisal system offered by domestic C2C e-commerce website ensures the network security to a certain extent while it has some problems in identity verification, evaluation rules and model, credit of buyers and sellers and so on. Focused on the largest national C2C shopping website—Taobao, this article mainly analyzes the present situations and problems of the credit appraisal system, puts forward some improved suggestions of the real-name authentication, credit and transaction appraisal rules and so forth, and then establishes improved credit appraisal system.

Experiences with SoftToken: a token‐based coordination layer for WLANs

SummaryThis paper presents our experiences with SoftToken protocol, a new contention‐free medium access control protocol for wireless local area network. This new mechanism adds a token‐passing procedure on top of Institute of Electrical and Electronics Engineers 802.11 for coordinating transmissions and avoiding collisions. With this extension, it becomes possible to offer differentiated services in a deterministic manner. In this paper, we provide a thorough performance evaluation of SoftToken in terms of its scalability, robustness and efficiency in comparison with Institute of Electrical and Electronics Engineers 802.11 and a time division multiple access (TDMA)‐based Wi‐Fi extension called Soft‐TDMA. Our evaluation is based on experiments run on different test beds covering different scenarios in a wired virtual network environment and practical wireless environments supporting different types of traffic. The results show that SoftToken indeed provides better QoS performance in scenarios that require service differentiation (e.g. mixed voice over Internet protocol and best effort traffic scenarios). Copyright © 2013 John Wiley & Sons, Ltd.

A Simulation Model of Object Movement for Evaluating the Communication Load in Networked Virtual Environments

In this paper, we propose a common simulation model that can be reused for different performance evaluations of networked virtual environments. To this end, we analyzed the common features of NVEs, in which multiple regions compose a shared space, and where a user has his/her own interest area. Communication architecture can be client-server or peer-server models. In usual simulations, users move around the world while the number of users varies with the system. Our model provides various simulation parameters to customize the region configuration and user movement pattern. Furthermore, our model introduces a way to mimic a lot of users in a minimal experiment environment. The proposed model is integrated with our network framework, which supports various scalability approaches. We specifically applied our model to the interest management and load distribution schemes to evaluate communication overhead. With the proposed simulation model, a new simulation can be easily designed in a large-scale environment.

A survey of peer-to-peer overlay approaches for networked virtual environments

This paper identifies and analyzes the key design approaches that have been proposed over the last decade to construct a peer-to-peer (P2P) networked virtual environment (NVE) systems. We discuss each approach, their advantages and drawbacks, and examine several representative P2P-based NVE systems based on the presented approaches, thus providing the background and literature review of P2P NVEs.

Experimental Design of Courses Based on the ARP Message Structure

Regarding the teaching of the course Computer Network, this article analyzes the MAC frame format and the structure of ARP message, designs a virtual machine test environment, and tries to structure the concept of ARP Messages in the virtual network environment which can be realized into practical methods. This method is conducive to the learning of the theories of the structure of ARP messages, providing a new way of thinking to explore from theories to the practice of the computer network courses.

Towards a Hierarchical Global Naming Framework in Network Virtualization

Network virtualization enables autonomous and heterogeneous Virtual Networks (VNs) to co-exist on a shared physical substrate. In a Network Virtualization Environment (NVE), the fact that individual VNs are underpinned by diverse naming mechanisms brings about an obvious challenge for transparent communication across multiple VN domains due to the complexity of uniquely identifying users. Existing solutions were mainly proposed compatible to Internet paradigm with little consideration of their applications in a virtualized environment. This calls for a scalable and efficient naming framework to enable consistent communication across a large user population (fixed or mobile) hosted by multiple VNs. This paper highlights the underlying technical requirements and presents a scalable Global Naming Framework (GNF), which (1) enables transparent communication across multiple VNs owned by the same or different SPs; (2) supports communication in the presence of dynamics induced from both VN and end users; and (3) greatly reduces the network operational complexity (space and time). The suggested approach is assessed through extensive simulation experiments for a range of network scenarios. The numerical result clearly verifies its effectiveness and scalability which enables its application in a large-scale NVE without significant deployment and management hurdles.

APRICOD

Content discovery is a major source of latency in peer-to-peer (P2P) media streaming systems, especially in the presence of noncontinuous user access, such as random seek in Video-on-Demand (VoD) streaming and teleportation in a Networked Virtual Environment (NVE). After the aforementioned user interactions, streaming systems often need to initiate the content discovery process to identify where to retrieve the requested media objects. Short content lookup latency is demanded to ensure smooth user experience. Existing content discovery systems based on either a Distributed Hash Table (DHT) or gossip mechanism cannot cope with noncontinuous access efficiently due to their long lookup latency. In this work, we propose an access-pattern-driven distributed caching middleware named APRICOD, which caters for fast and scalable content discovery in peer-to-peer media streaming systems, especially when user interactions are present. APRICOD exploits correlations among media objects accessed by users, and adapts to shift in the user access pattern automatically. We first present a general APRICOD design that can be used with any existing content discovery system. We then present an implementation of APRICOD on top of Pastry, which we use to evaluate APRICOD. Our evaluation in a 1024-node system, using a Second Life trace with 5,735 users and a VoD trace with 54 users, shows that APRICOD can effectively resolve all continuous access queries with a single hop deterministically with node failure as an exception, and resolve noncontinuous access queries with a single hop with high probability.

Greener networking in a network virtualization environment

Energy consumption of network operators can be minimized by the dynamic and smart relocation of networking resources. In this paper, we propose to take advantage of network virtualization to enable a smart energy aware network provisioning. The virtualization of networking resources leads to the problem of mapping virtual demands to physical resources, known as Virtual Network Embedding (VNE). Our proposal modifies and improves exact existing energy aware VNE proposals where the objective is to switch off as many network nodes and interfaces as possible by allocating the virtual demands to a consolidated subset of active physical networking equipment. As exact energy efficient VNE approaches are hard to solve for large network sizes and have an adverse effect in the number of successful embeddings, an heuristic approach to reconfigure the allocation of already embedded virtual networks, minimizing the energy consumption, is also proposed.

Caffe Neve

The popularization of podcasting provides Internet users more opportunities to access interesting and entertaining multimedia content. The podcasting content hosting sites became the shared platforms for all Internet users to access third-party contributions. More and more Internet users are encouraged to become active content providers that share their resources and multimedia productions. Building a large scale multi-user 3D application can benefit from the same content distribution pattern as the development cost can be distributed if the application implementation is outsourced. The application is constructed by integrating 3D content from various third-party service providers. In addition, the implementation outsourcing can inspire contributors to provide creative application content. Unfortunately, sharing and distributing 3D resources are more challenging and the podcasting framework cannot resolve the problems effectively. We introduce a standardized framework that supports the seamless integration of distributed 3D resources as coarse-grained components of constructed Distributed Virtual Environments (DVEs). Component Application Framework For Extensible NEtworked Virtual Environments (Caffe Neve) uses service-oriented architecture (SOA) and incorporates streaming technology for dynamic content delivery. Using Caffe Neve, third-party developers can create distributed services to stream 3D content. The framework provides an application integrator that constructs a shared virtual environment and delivers the application content to the end users. In this paper we describe the framework details. The application integration infrastructure of the framework is designed based on a distributed Model-View-Controller model. The framework uses an ontology to support the semantic level content integration and service coordination. In addition, the framework incorporates streaming within the architecture for the real-time data delivery and improved performance. By deploying services within the framework, 3D resource owners can conveniently podcast or broadcast their 3D content to the end users. In the end, we demonstrate how to use the framework to construct 3D podcast and broadcast applications. Regardless of the type of 3D applications and delay tolerance, performance is important and has to be carefully studied. We evaluate the framework performance by examining the sample application and present the analysis results. We also present the experiment results on the simulated framework application in large scale by using simulation tools.

IDM: An Indirect Dissemination Mechanism for Spatial Voice Interaction in Networked Virtual Environments

One type of Peer-to-Peer (P2P) live streaming has not yet been significantly investigated, namely topologies that provide many-to-many, interactive connectivity. Exemplar applications of such P2P systems include spatial audio services for networked virtual environments (NVEs) and distributed online games. Numerous challenging problems have to be overcome-among them providing low delay, resilience to churn, effective load balancing, and rapid convergence-in such dynamic environments. We propose a novel P2P overlay dissemination mechanism, termed IDM, that can satisfy such demanding real-time requirements. Our target application is to provide spatialized voice support in multiplayer NVEs, where each bandwidth constrained peer potentially communicates with all other peers within its area-of-interest (AoI). With IDM each peer maintains a set of partners, termed helpers, which may act as stream forwarders. We prove analytically that the system reachability is maximized when the loads of helpers are balanced proportionally to their network capacities. We then propose a game-theoretic algorithm that balances the loads of the peers in a fully distributed manner. Of practical importance in dynamic systems, we prove that our algorithm converges to an approximately balanced state from any prior state in rapid O(\log \log n) time, where n is the number of users. We further evaluate our technique with simulations and show that it can achieve near optimal system reachability and satisfy the tight latency constraints of interactive audio under conditions of churn, avatar mobility, and heterogeneous user access network bandwidth.

Effect of packet loss on collaborative haptic interactions in networked virtual environments

It has been widely demonstrated that haptic interaction can enrich the sense of copresence of distributed users and improve their performance in collaborative virtual environments CVEs. However, th...

The Study on Test Technologies of C<sup>3</sup>I Network Equipments

C3I network equipments, with complex architecture, deal with quantities of information from the aspect of time and space, which makes them difficult to support. This paper adopts automatic test and diagnosis techniques, analog networking technique and active test method to satisfy the requirements of timeliness, intelligence and high precision in fault location. A virtual network environment is built to complete the network equipments’ test. It is significant to the complex network equipments’ test and diagnosis.

1A2-R03 VR中での鍵盤操作を対象とした力覚特性(VRとインタフェース)

There is currently much discussion of Quality of Service(QoS) measurement at the network level of real-time multimedia services. The presence of a network brings up a number of issues. In case of visual or auditory interaction, the effect of such issues have been treated by many researchers and the effective countermeasure have been proposed. A haptic Interface is a useful device in virtual reality technology and users can make a feeling of touching virtual object. Especially, in a virtual environment connected by a network system, users can share tasks and feelings. However, with a networked virtual environment, the haptic interface will make an unstable behavior because of a communication delay. This experiment focuses on a keyboard interface which uses haptic interacting with virtual space surrounding user. We have also constructed a 3D haptic interaction system, whereby the user can see and touch virtual objects by using a haptic device. However, new methods are known about the relationship between network issues and networked haptic interface in virtual environments. This experiment shows ethernet data transmission on purpose of packet delay and packet loss for transmission, with a few statistical analysis and traditional coding scheme.

Towards full network virtualization in horizontal IaaS federation: security issues

Horizontal IaaS federation exploits datacenter for federation of IaaS provider by supplying virtual nodes (e.g. virtual machines, virtual switches, and virtual routers) and virtual links. Today's datacenters for cloud computing do not supply full network virtualization in terms of user-level network management and user-agreed network topology. The datacenters lack the basic security services required for the collocation of tenants' virtual networks. The network virtualization research projects from academia and industry support full network virtualization but lack the basic security services required for the collocation of tenants' virtual networks. This paper investigates the security issues in four areas namely, (a) monolithic IaaS cloud, (b) network virtualization research projects, (c) datacenter network virtualization and (d) virtual resources to incorporate full network virtualization environment in horizontal IaaS federation. Further, it presents the security related qualitative comparisons of datacenters, network virtualization research projects and virtual resources to incorporate full network virtualization in horizontal IaaS federation.

Novel End-to-End Quality of Service Provisioning Algorithms for Multimedia Services in Virtualization-Based Future Internet

Network virtualization has been proposed as a key contribution to the future internetworking paradigm and is expected to play a crucial role in the next generation Internet. Although interesting progress has been made towards network virtualization, end-to-end Quality of Service (QoS) provisioning for multimedia services in network virtualization environments is still an important open topic. In this paper, we tackle this challenging issue by modeling multimedia service delivery in network virtualization and proposing efficient path selection algorithms for virtual networks. The main contributions of this paper are a model for the end-to-end multimedia service delivery in network virtualization environments, proposal of efficient algorithms for selecting paths traversing the network infrastructure for QoS provisioning in virtual networks, and analysis of the effectiveness and efficiency of the proposed algorithms. Both theoretical analysis and experimental results show that the modeling technique and the algorithms proposed in this paper are general and flexible, and therefore applicable to the delivery of multimedia content in various heterogeneous networking systems in the next generation Internet.

Service Fault Diagnosis Algorithm in Network Virtualization Environment

PDF HTML阅读 XML下载 导出引用 引用提醒 网络虚拟化环境下的服务故障诊断算法 DOI: 10.3724/SP.J.1001.2012.04171 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金(60973108, 60902050, 61121061); 国家高技术研究发展计划(863)(2011AA05A116, 2011AA01A102); 国家教育部博士点基金(20110005110011) Service Fault Diagnosis Algorithm in Network Virtualization Environment Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:网络虚拟化环境下,底层网络的透明性造成虚拟网提供商不能诊断所有的虚拟网服务故障.为解决此问题,提出了基于映射关系的虚拟网服务故障传播模型.针对故障传播模型中故障集与症状集较大、网络环境动态和噪声大而导致的已有诊断算法误报率高、时间复杂度高的问题,基于网络虚拟化环境下症状内在相关性特点,提出了一种新的基于症状内在相关性的虚拟网服务故障诊断算法 SFDoIC(service fault diagnosis algorithm based oninherent correlation among symptoms).仿真实验结果表明,SFDoIC 算法能够很好地解决底层网络透明性造成的虚拟网服务故障难以定位的问题.SFDoIC 算法可以有效地降低诊断算法的误报率,显著缩短诊断算法的运行时间. Abstract:The virtual network provider (VNP) cannot diagnose all service faults of virtual networks, because thesubstrate network is transparent for VNP within the network virtualization environment. To solve this problem, thepaper presents a service fault propagation model based on mapping relationships. In terms of the large fault set, thelarge symptom set, and noisy and dynamic environments, which result in the higher false positive rate and thelonger running time of existing fault diagnosis algorithms, a service fault diagnosis algorithm based on inherentcorrelation among symptoms (SFDoIC), is proposed. Simulation results show that algorithm SFDoIC can solve thedifficult problems in fault diagnosis that are caused by the transparency of the substrate network for VNP,effectively reducing the false positive rate and decreasing running time. 参考文献 相似文献 引证文献

Supporting Fine-Grained Concurrent Tasks and Personal Workspaces for a Hybrid Concurrency Control Mechanism in a Networked Virtual Environment

A concurrency control mechanism for a networked virtual environment is a key element in many collaborative computer-aided design applications. However, conventional object-based locking mechanisms restrict the behaviors of nonowners, and an attribute-based locking mechanism may produce another problem called task-surprise, which disturbs users' collaboration. In this paper, we propose a hybrid concurrency control mechanism that reduces restrictions of nonowners' behaviors and task-surprises in a networked virtual environment. The proposed method consists of two concurrency control approaches: task-based concurrency control and personal workspaces. The task-based concurrency control approach allows nonowners to do some tasks if they do not conflict with the tasks of the owner of the shared object. The personal workspaces approach provides an independent workspace where a user can manipulate copies of the shared objects. The proposed method was applied to a collaborative level design for a large-scale online game as a case study. We evaluated its performance by experiments and user studies to check acceptance and usability of the proposed method.