Routing and resource optimization in service overlay networks

Service Overlay Networks (SONs) create a virtual topology on top of the Internet and provide end-to-end quality of service guarantees without requiring support by the underlying network.The optimization of the resources utilized by an SON is a fundamental issue for an overlay operator owing to the costs involved and the need to satisfy user requirements. Careful decisions are necessary to provide enough capacity to overlay links, to route traffic, to assign users to access nodes and to deploy overlay nodes.In this paper, we propose two mathematical programming models for the user assignment problem, the traffic routing optimization and the dimensioning of the capacity reserved on overlay links in SONs. The first model minimizes the SON installation cost while providing full access to all users. The second model maximizes the SON profit by selecting which users to serve, based on the expected gain, and taking into consideration budget constraints of the SON operator. Moreover, we extend these models to include the optimization of the number and position of overlay nodes.We provide the optimal solutions of the proposed SON design formulations on a set of realistic-size instances and discuss the effect of different parameters on the characteristics of the planned networks. Numerical results show that the proposed approach is able to solve the problem to the optimum even for large-scale networks.     

A novel pricing approach to support QoS in 3G networks

Pricing in 3G and other communication networks may control and manage the utilisation of network resources. The available network resources get strained with increased usage levels, which results in poor service to the users. Most users prefer receiving high quality services at affordable costs. This requires the provision of QoS guarantees for network services at a low cost. In a real business scenario, this relationship is hard to achieve; moreover revenue sources for network operators have been shifting from the provision of network access to provisioning of rich services, e.g. multimedia services. To attain a functional compromise, we propose a pricing scheme that relies on service profiles to manage resource utilisation in a DiffServ-enabled 3G network. The service profiles define the QoS achieved for accessing services through a common resource pool, in which resource sharing is used to maximise network resource utilisation, user satisfaction and profits for the network operators. In an NGN scenario users would select pricing profiles according to their budgets, and the network will map these profiles to a set of QoS options that may translate to the choice of an access network for service access. In this paper, we present the mathematical model of the proposed pricing scheme, the proposed design of an evaluation framework, QoS performance results, and a service provisioning scenario illustrating the applicability of the proposed pricing scheme.     

A study of traffic, user behavior and pricing policies in a large campus network

Tsinghua University campus network is a large campus network in China, providing volume-based and flat-rate Internet access service for more than 31,000 students and staff. In order to better understand its traffic, user behavior and pricing policies to facilitate network planning and management, we collect a one-year-long flow-based traffic log and a 10-year-long user-based log at the boundary of this campus network, and then conduct an analysis study on these two data sets. In this paper, we first present characteristics of inbound traffic flows from the aspects of traffic prediction and inference. Then we analyze the geographical origins of incoming flows, and the result reveals that USA, Japan and Korea are the most important source countries of international traffic. Our user-based investigation shows that the properties of users have important influence on their behavior, e.g., major has stronger influence on users’ online time, while occupation has stronger influence on users’ international traffic volume. We also find that there are more and more users choosing flat rate pricing scheme instead of volume based pricing scheme, and these users tend to over-provision when they subscribe from tiered pricing options.     

Pricing Internet services: proposed improvements

Flat-rate pricing appeals to Internet users and service providers because of its simplicity and predictability. However, congestion is the inevitable consequence of flat-rate pricing because Internet users who pay a fixed access fee have no incentive to limit their network usage. Future applications that require timely delivery of data will require mechanisms for allocating network resources that give consumers choices in services and prices while allowing service providers to recover their costs. We examine the proposed improvements in Internet pricing that are designed to increase its economic efficiency and support the deployment of new applications that require a better quality of service than the Internet currently offers     

CycloidGrid: A proximity-aware P2P-based resource discovery architecture in volunteer computing systems

Volunteer computing which benefits from idle cycles of volunteer resources over the Internet can integrate the power of hundreds to thousands of resources to achieve high computing power. In such an environment the resources are heterogeneous in terms of CPU speed, RAM, disk capacity, and network bandwidth. So finding a suitable resource to run a particular job becomes difficult. Resource discovery architecture is a key factor for overall performance of peer-to-peer based volunteer computing systems. The main contribution of this paper is to develop a proximity-aware resource discovery architecture for peer-to-peer based volunteer computing systems. The proposed resource discovery algorithm consists of two stages. In the first stage, it selects resources based on the requested quality of service and current load of peers. In the second stage, a resource with higher priority to communication delay is selected among the discovered resources. Communication delay between two peers is computed by a network model based on queuing theory, taking into account the background traffic of the Internet. Simulation results show that the proposed resource discovery algorithm improves the response time of user’s requests by a factor of 4.04 under a moderate load.     

Video placement and configuration of distributed video servers on cable TV networks

A large-scale, distributed video-on-demand (VOD) system allows geographically dispersed residential and business users to access video services, such as movies and other multimedia programs or documents on demand from video servers on a high-speed network. In this paper, we first demonstrate through analysis and simulation the need for a hierarchical architecture for the VOD distribution network.We then assume a hierarchical architecture, which fits the existing tree topology used in today's cable TV (CATV) hybrid fiber/coaxial (HFC) distribution networks. We develop a model for the video program placement, configuration, and performance evaluation of such systems. Our approach takes into account the user behavior, the fact that the user requests are transmitted over a shared channel before reaching the video server containing the requested program, the fact that the input/output (I/O) capacity of the video servers is the costlier resource, and finally the communication cost. In addition, our model employs batching of user requests at the video servers. We study the effect of batching on the performance of the video servers and on the quality of service (QoS) delivered to the user, and we contribute dynamic batching policies which improve server utilization, user QoS, and lower the servers' cost. The evaluation is based on an extensive analytical and simulation study.     

How to charge for network services – flat-rate or usage-based?

Currently, the Internet service provider market offers two different types of pricing plans. In the USA, the predominant pricing plan is a flat-rate plan. In Europe and Asia, the predominant one is a per-minute pricing plan. Enrolled in such a pricing plan, users have to pay for the connect time to the Internet. Although Internet Service Providers (ISPs) have competed heavily for users in these last few years, they only have focused on trying to offer the lowest price within such pricing plans. A potentially more profitable and sustainable method of doing business would be for ISPs to differentiate themselves by offering more customized pricing plans for certain user groups. An important question then is whether a pricing plan exists that is attractive to users, but also allows ISPs to build a sustainable business. Based on empirical results of the INternet Demand EXperiment (INDEX) project, we discuss a pricing plan for Internet access that appears to be appreciated by Internet users as well as by ISPs. This pricing plan combines the advantages of flat-rate pricing and usage-based pricing. Users will benefit by receiving unlimited access to a basic service with the choice of higher quality of service (QoS) whenever they demand. From the ISPs' perspective, such a pricing plan will help any ISP to focus on certain user groups and to reduce peak network load.     

Session based access control in geographically replicated Internet services

Performance critical services over Internet often rely on geographically distributed architectures of replicated servers. Content Delivery Networks (CDN) are a typical example where service is based on a distributed architecture of replica servers to guarantee resource availability and proximity to final users. In such distributed systems, network links are not dedicated, and may be subject to external traffic. This brings up the need to develop access control policies that adapt to network load changing conditions. Further, Internet services are mainly session based, thus an access control support must take into account a proper differentiation of requests and perform session based decisions while considering the dynamic availability of resources due to external traffic.In this paper we introduce a distributed architecture with access control capabilities at session aware access points. We consider two types of services characterized by different patterns of resource consumption and priorities. We formulate a Markov Modulated Poisson Decision Process for access control that captures the heterogeneity of multimedia services and the variable availability of resources due to external traffic. The proposed model is optimized by means of stochastic analysis, showing the impact of external traffic on service quality. The structural properties of the optimal solutions are studied and considered as the basis for the formulation of heuristics. The performance of the proposed heuristics is studied by means of simulations, showing that in some typical scenario they perform close to the optimum.     

Design of Common Resource Management and Network Simulator in Heterogeneous Radio Access Network Environment

By the newly emerging radio access technologies, we face the new heterogeneous network environment. Focusing on the co-existence of multiple access networks and the complex service combinations, the wireless service operators should guarantee good quality of services for every user. Thus, the service operators build a new operation framework which combines the existing networks and newly adopted ones. Our objective is finding the optimal heterogeneous network operation framework. We suggest the market-based marginal cost function for evaluating the relative value of resources for each network and develop a whole new heterogeneous network operation framework. To prove the applicability of the proposed operation framework, we build a large-scale JAVA simulator. We can easily test the various service scenarios in heterogeneous network environment by the simulator.     

Double-sided auctions applied to vertical handover for mobility management in wireless networks

In the next generation Internet, we have seen the convergence of multimedia services and Internet with the mobility of users. Vertical handover decision (VHD) algorithm are essential components of the mobility management architecture in mobile wireless networks. VHD algorithms help mobile users to choose the best mobile network to connect among available candidates. It also can help the network manager to optimize easily the limited resources shared among the network providers and the users. In this article, we formulate VHD algorithm as a resource allocation problem for down-link transmission power in multiple W-CDMA networks and show how combinatorial double-sided auctions can be applied to this specific problem. The proposed pricing schemes make use of the signal interference to noise ratio, achievable data rates, power allocation at mobile networks, and monetary cost as decision criteria and our model differentiate between new calls and on-going communications to take into account that the last category has somewhat more importance. Several combinatorial double-sided auction are proposed to maximize the social welfare and /or to provide incentives for mobile users and mobile operators to be truth-telling in terms of valuation or cost. Finally, the economic properties of the different proposed pricing schemes are also studied by means of simulations.     

SLA-based QoS pricing in DiffServ networks

The availability of high-speed transmission media and networking equipment in contemporary networks, as well as the evolution of quality-demanding applications has focused research interest on the provision of advanced qualitative services in addition to the traditional best-effort model of the Internet. A number of alternatives for service differentiation and QoS provisioning have been proposed and standardized, but in the case of backbone, transport networks the DiffServ architecture has prevailed, due to its scalability and deployment feasibility. The provisioning of services according to the DiffServ framework has in turn raised the requirements for interdependent, controlled resource allocation and service pricing, with particular needs for pricing mechanisms that preserve the potential and flexibility of DiffServ. At the same time, such mechanisms should reflect resource usage, allocate resources efficiently, reimburse costs or maximize service provision profits and lead customers to requesting services that will maximize their revenue. In this work, after reviewing related research, the principles that a pricing scheme for DiffServ-based services should follow are presented, stressing the differences form traditional Internet pricing. Based on these principles, an analytical approach to pricing a particular class of DiffServ-based services and a methodology for applying this approach in a real network are proposed and evaluated.     

Enhanced streaming services in a content distribution network

Prism's content naming, management, discovery, and redirection mechanisms support: high-quality streaming media services in an IP-based content distribution network. IP content distribution networks (CDNs) are special-purpose networks that provide scalability by distributing many servers across the Internet “close” to consumers. Prism (Portal infrastructure for Streaming Media) is a CDN architecture for: distributing, storing, and delivering high quality streaming media over IP networks. The Prism-based stored-TV (STV) service allows users to select content based on the program's name as well as the time it was aired. Content stored inside the network is accessible throughout the whole Prism infrastructure. For example, a user in the US can access European TV content both live and on-demand. Prism also allows users to specify content to be stored in a “network-VCR” type service. The authors introduce the components of the Prism architecture     

Internet access to a home area network

The AutoHan project implements a self-configuring software architecture for home area networks that offers an XML-based registry and HTTP-based service. The article begins by introducing the low-level architectures of the AutoHan project that enable different networking technologies to interoperate and define one logical IP network. It then describes the two core services that enable resources to export, discover and interoperate with AutoHan by using these low-level architectures. Finally, the article discusses naming and addressing issues for Internet access and shows how XML and HTTP allowed extension of the system to support Internet access through IHan (Internet home area network)     

面向多租户网络资源分配的博弈优化策略

为了应对5G及未来网络中用户间差异化的服务需求,改善多租户网络切片资源利用率低和部署成本高的问题,提出一种基于多租户网络资源分配的博弈优化策略。在多租户网络中,网络切片租户（NSTs）租用基础设施提供商基站的无线频谱资源,将接入服务切片构建为网络切片即服务,为用户提供网络接入服务。将NSTs和用户的关系建模为一个多主多从的Stackelberg博弈,引入切片流行度和服务命中率指标,建立博弈双方的策略空间和收益函数,并证明NSTs的切片订购策略存在唯一的纳什均衡。通过逆向归纳法分析博弈模型,提出一种分布式迭代算法求得用户的最优吞吐量需求以及NSTs的最优切片定价。仿真结果表明,与传统考虑切片资源分配的优化策略对比,基于多租户网络资源分配的博弈优化策略能够有效提高资源利用率和用户满意度,并降低切片部署能耗,较好地实现频谱带宽资源的合理分配。     

Efficient Agent-Based Selection of DiffServ SLAs over MPLS Networks Within the ASP Service Model

The demand for QoS provisioning support over Internet grows continuously. One of the factors contributing to this demand is the increasing penetration of Application Service Providers (ASPs) to the market. This necessitates the development of mechanisms for the efficient realization of Service Level Agreements (SLA). In this paper, we develop and evaluate an approach for efficient SLA selection and implementation (support, policing/shaping, and charging) in a DiffServ-over-MPLS network domain. We describe how this approach is applied in a realistic service provision scenario based on the ASP service model. A negotiation process between a user and a network provider is introduced; thus the user can choose from the alternative options for allocation of resources the one that better matches his needs. For the purposes of negotiation, we develop an appropriate utility model that expresses user preferences in a simple yet informative way. Furthermore, we discuss the implementation of our approach in a small-scale experimental DiffServ-over-MPLS network, for the case of a simple scenario of ASP services provision. We also assess the economic efficiency of our approach by means of simulation experiments, the results of which advocate that our approach is incentive compatible, in the sense that individual optimization by each user (in SLA selection) also leads to improved social welfare. Our approach is quite general and can be combined with several policies for network management, or as a complement to the traffic engineering procedures.     

Access and service convergence over the mobile internet – A survey

Next generation heterogeneous wireless networks are expected to interwork with Internet Protocol (IP)-based infrastructures. Conventional network services operate like silos in that a specific set of services are offered over a specific type of access network. It is desirable for users to be able to roam between fixed and mobile networks that employ different access technologies. Therefore, mobility management with quality of service (QoS) support is of particular importance and one of the driving forces of convergence. Since service providers often provide more than one service to their subscribers, it is important to facilitate convergence of network charging architecture through a common charging framework. One of the main issues of IP-based convergence is security and privacy. This requires coordination of different security policies in diverse networks that have different security levels and capabilities. The business case for migration to an IP-based platform motivates operators to deliver more powerful services for customers as well as a better user experience. This paper provides an overview of converged mobile Internet architectures and their implications on QoS, charging/billing and security, as well as emerging business models for telecommunication services.     

Generic user revocation systems for attribute-based encryption in cloud storage

Cloud-based storage is a service model for businesses and individual users that involves paid or free storage resources. This service model enables on-demand storage capacity and management to users anywhere via the Internet. Because most cloud storage is provided by third-party service providers, the trust required for the cloud storage providers and the shared multi-tenant environment present special challenges for data protection and access control. Attribute-based encryption (ABE) not only protects data secrecy, but also has ciphertexts or decryption keys associated with fine-grained access policies that are automatically enforced during the decryption process. This enforcement puts data access under control at each data item level. However, ABE schemes have practical limitations on dynamic user revocation. In this paper, we propose two generic user revocation systems for ABE with user privacy protection, user revocation via ciphertext re-encryption (UR-CRE) and user revocation via cloud storage providers (UR-CSP), which work with any type of ABE scheme to dynamically revoke users.     

分布式开放存取期刊爬虫的设计与实现

开放存取（open access,OA）期刊属于网络深层资源且分散在互联网中,传统的搜索引擎不能对其建立索引,不能满足用户获取OA期刊资源的需求,从而造成了开放资源的浪费。针对如何集中采集万维网上分散的开放存取期刊资源的问题,提出了一个面向OA期刊的分布式主题爬虫架构。该架构采用主从分布式设计,提出了基于用户预定义规则的OA期刊页面学术信息提取方法,由一个主控中心节点控制多个可动态增减的爬行节点,采用基于Chrome浏览器的插件机制来实现分布式爬行节点的可扩展性和部署的灵活性。     

An enhanced framework for providing multimedia broadcast/multicast service over heterogeneous networks

Multimedia broadcast multicast service （MBMS） with inherently low requirement for network resources has been proposed as a candidate solution for using such resources in a more efficient manner. On the other hand, the Next Generation Mobile Network （NGMN） combines multiple radio access technologies （RATs） to optimize overall network performance. Handover performance is becoming a vital indicator of the quality experience of mobile user equipment （UE）. In contrast to the conventional vertical handover issue, the problem we are facing is how to seamlessly transmit broadcast/multicast sessions among heterogeneous networks. In this paper, we propose a new network entity, media independent broadcast multicast service center （MIBM-SC）, to provide seamless handover for broadcast/multicast sessions over heterogeneous networks, by extensions and enhancements of MBMS and media independent information service （MIIS） architectures. Additionally, a network selection scheme and a cell transmission mode selection scheme are proposed for selecting the best target network and best transmission mode. Both schemes are based on a load-aware network capacity estimation algorithm. Simulation results show that the pro- posed approach has the capability to provide MBMS over heterogeneous networks, with improved handover performance in terms of packet loss rate, throughput, handover delay, cell load, bandwidth usage, and the peak signal-to-noise ratio （PSNR）.