可扩展网络服务模型的服务扩展能力分析

网络的服务扩展能力是下一代网络的重大需求,也是网络服务模型技术发展的主要挑战。可扩展网络服务模型正是应网络发展的这一需求而提出的。概述了该服务模型的基本概念与原理;从原理分析的角度对该服务模型的服务扩展能力进行了定性分析;使用网络服务扩展能力的分析方法,从理论和网络实际应用2个角度选用实例对该服务模型的服务扩展能力的进行了定量分析。由定性分析与定量分析结果可知,可扩展网络服务模型具有很好的服务扩展能力。

Cloud Computing as Area of Modem Industry

Cloud computing is a new vision about the needs of information technology （IT）. It provides a comprehensive concept for building a homogeneous environment through services offered in the cloud Software-as-a-Service （SaaS）, Platform-as-a-Service （PaaS）, and Infrastructure-as-a-Service （IaaS）. Cloud computing is location-independent computing, whereby shared servers provide resources, software, and data to computers and other devices on demand, as with the electricity grid. Cloud computing is computing paradigm that is driven by economies of scale, in which a set of dynamically-scalable resources such as servers, storages, platforms, and services are delivered on demand to the customers over the interuet. ＂Cloud computing is a continuation of the direction the industry has been going for the last several years in terms of using shared and elastically scalable computing resources,＂ says Rex Wang1, VP of Product Marketing at Oracle, who spoke at the Gartner Data Center Conference, in January 2011. Cloud computing refers to dynamic provision of virtual distributed computational resources on demand via a computer network. Cloud computing is a new high technology industry that possesses a number of advantages over existing business practices： a reduction of expenses, technical staff, and efforts of the end users.

Intelligent Server Management Framework over Extensible Messaging and Presence Protocol

With the increasing importance of cloud services worldwide, the cloud infrastructure and platform management has become critical for cloud service providers. In this paper, a novel architecture of intelligent server management framework is proposed. In this framework, the communication layer is based on the Extensible Messaging and Presence Protocol (XMPP), which was developed for instant messaging and has been proven to be highly mature and suitable for mobile and large scalable deployment due to its extensibility and efficiency. The proposed architecture can simplify server management and increase flexibility and scalability when managing hundreds of thousands of servers in the cloud era.

Stumbling Blocks in Cloud Computing Adoption Pathway： A Charter

Cloud computing is currently an embryonic domain in the area of information technology that possesses the power of transforming the way information technology （IT） services are delivered and maintained in the business world. Pay as per the usage kind of cost structure coupled with delivery of computing services through internet makes cloud computing an exciting and potential growth oriented information technology model compared with conventional computing services delivery models. Various additional features like scalability, flexibility and easy deployment process creates a window for the organizations even relatively smaller in size to get benefitted by the highly advanced ＆ modern technologies without incurring substantial cost. In spite of so many benefits of this new delivery model, concerns are beginning to grow about how safe an environment it is. Despite of all the hype surrounding the cloud, enterprise customers are still reluctant to deploy their business in the cloud. Security is one of the major issues which reduces the growth of cloud computing and complications with data privacy and data protection continue to plague the market. Other related concerns associated with the adoption of cloud computing include trust on service providers, loss of control and compliance issues. This paper is an attempt to explore security ＆ trust issues linked with cloud computing adoption in the Small and Medium Enterprises （SME） sector.

An approach to quality assessment for web service selection based on the analytic hierarchy process for cases of incomplete information

Since web services intended for the same application environment tend to be functionally homogeneous, researchers have turned to their non-functional aspects in order to constructively compare web services and choose an appropriate one. In general, quality of service is very important to users. Many schemes that consider quality assessment have been proposed for web service selection. With the increasing number of qualityrelated attributes, an effective quality assessment method needs satisfactory scalability. Schemes based on the analytic hierarchy process(AHP) meet this requirement. However, prevalent methods in this vein overlook the fact that the traditional AHP needs a complete judgment matrix. In practice, all the information needed to construct a judgment matrix is often unavailable for a variety of reasons, due to which certain judgments cannot be made. In this paper, for an incomplete judgment matrix, we propose an improved AHP approach to consistency verification and the subsequent ordering. Our method can deal with situations where information is insufficient,and inherits all the merits of the traditional AHP approach. A case study establishes the effectiveness of our proposed method.

A scalable and efficient IPv4 address sharing approach in IPv6 transition scenarios

IPv6 has been an inevitable trend with the depletion of the global IPv4 address space. However, new IPv6 users still need public IPv4 addresses to access global IPv4 users/resources, making it important for providers to share scarce global IPv4 addresses effectively. There are two categories of solutions to the problem, carrier-grade NAT （CGN） and ＇A＋P＇ （each customer shaving the same IPv4 address is assigned an excluded port range）. However, both of them have limitations. Specifically, CGN solutions are not scalable and can bring much complexity in managing customers in large-scale deployments, while A＋P solutions are not flexible enough to meet dynamic port requirements. In this paper, we propose a hybrid mechanism to improve current solutions and have deployed it in the Tsinghua University Campus Network. The real traffic data shows that our mechanism can utilize limited IPv4 addresses efficiently without degrading the performance of applications on end hosts. Based on the enhanced mechanism, we propose a method to help service providers make address plans based on their own traffic patterns and actual requirements.