一种基于QoS的Internet服务管理体系结构

服务定位协议(SLP)是IETF提出的基于IP网络的服务定位标准。而这一标准并没有考虑对QoS的支持。未来的互联网络是一个具有QoS保证的网络。服务发现仅仅是Internet服务管理中的一个方面，发现服务不是最终目的，最终目的是为了使用这一服务。在对SLP体系结构、下一代互联网QoS服务管理及相关技术充分研究的基础上，提出了一种新奇的基于QoS的Internet服务管理体系结构模型。为使在服务表示与发现层支持QoS，对SLP定位协议进行了一些扩充。对服务定位协议扩充后，当用户代理在向服务代理发布请求时，可以在请求消息中绑定QoS对象参数，一旦服务代理接收到这一消息，就可以利用这些QoS参数与域管理器进行协商，协商结果可通过服务代理反馈给用户代理。这样不仅减小了网络开销，而且降低了传统的用户代理与域管理器协商的次数，在服务发现的同时用户代理还可以直接获得该服务的QoS信息。     

Optimization of QoS parameters using scheduling techniques in heterogeneous network

Multimedia applications in wireless communication have been increased in recent years. A variety of wireless access technologies is introduced for various needs. The abundant increase in mobile computing devices and different networking systems leads to the support of user’s mobility on heterogeneous network. In general, the roaming users migrate between two different wireless technologies and their service must be supported by vertical handover (HO). Since the roaming users expect a rapid handover experience while switching from one wireless network to another, the handover operation must be enhanced by the networks. Various wireless technologies such as wireless LAN, Worldwide Interoperability for Microwave Access (WiMAX), and the 3G Partnership Project (3GPP) are interlaced to support many wireless services in rural, urban, and global scenarios. Moreover, quality of service (QoS) has become more significant in many applications where wireless network resources are utilized. In this paper, a handover management scheme is proposed for QoS enhancement in roaming users between WiMAX and WLAN by subscribers of networks belonging to the 3GPP standards. The proposed algorithms genetic queuing, proportionally fair queuing, and WiMAX aware load balancing are analyzed in the scheduling process during handover. The simulation is implemented using NS–2 and the experimental results are obtained for the proposed algorithms and compared with the standard scheme.     

The relationship between quality of service perceived and delivered in mobile Internet communications

Today mobile network operators offer a wide variety of mobile Internet services to their customers including mobile email, banking, and news services. The acceptance of these services is heavily based on quality of service (QoS) experienced by the user. So far the discussion of QoS has been very network centric and the key to user satisfaction has been the network performance. In this paper we analyze the relationship between QoS perceived by the customer and network performance offered by the service provider. We conduct a lab experiment where network performance variables were controlled. Statistical analysis of the results indicates that there is no 1:1 correspondence or even truly linear relationship between network performance and perceived QoS as recommended by the International Telecommunications Union-Telecommunication (ITU-T). Instead the relationship varied from application to application. We examine several usability factors as potential reasons behind this phenomenon and make suggestions for future research.     

无线传感器网络基于模糊信息的QoS路由发现方法

有效使用片上受限资源以保持最长的生命周期是无线传感器网络的核心问题.无线传感器网络不断增长的多媒体应用引发人们研究如何满足具体应用的服务质量约束.能量因素与QoS各参数的相互影响构成了一个NP完全问题.本文引入模糊数学理论中的区间数概念抽象现实网络提供的信息,利用排队论方法将多业务多类型QoS多参数的约束和目标简化,从而得到了一种满足多类型业务多参数QoS要求的路由算法.仿真实验结果表明,在满足多类型业务多参数QoS要求的前提下,本文算法能很好支持多种业务的资源需求分配,可达到全网最优能耗均衡,延长网络寿命.     

Wireless LAN load balancing with genetic algorithms

In recent years IEEE 802.11 wireless local area networks (WLANs) have become increasingly popular. Consequently, there has also been a surge in the number of end-users. The IEEE 802.11 standards do not provide any mechanism for load distribution and as a result user quality of service (QoS) degrades significantly in congested networks where large numbers of users tend to congregate in the same area. The objective of this paper is to provide load balancing techniques that optimise network throughput in areas of user congestion, thereby improving user QoS. Specifically, we develop micro-genetic and standard genetic algorithm approaches for the WLAN load balancing problem, and we analyse their strengths and weaknesses. We also compare the performance of these algorithms with schemes currently in use in IEEE 802.11 WLANs. The results demonstrate that the proposed genetic algorithms give a significant improvement in performance over current techniques. We also show that this improvement is achieved without penalising any class of user.     

Service level agreements (SLAs) parameter negotiation between heterogeneous 4G wireless network operators

We are currently witnessing a growing interest of network operators to migrate their existing 2G/3G networks to 4G technologies such as long-term evolution (LTE) to enhance the user experience and service opportunities in terms of providing multi-megabit bandwidth, more efficient use of radio networks, latency reduction, and improved mobility. Along with this, there is a strong deployment of packet data networks such as those based on IEEE 802.11 and 802.16 standards. Mobile devices are having increased capabilities to access many of these wireless networks types at the same time. Reinforcing quality of service (QoS) in 4G wireless networks will be a major challenge because of varying bit rates, channel characteristics, bandwidth allocation and global roaming support among heterogeneous wireless networks. As a mobile user moves across access networks, to the issue of mapping resource reservations between different networks to maintain QoS behavior becomes crucial. To support global roaming and interoperability across heterogeneous wireless networks, it is important for wireless network operators to negotiate service level agreement (SLA) contracts relevant to the QoS requirements. Wireless IP traffic modeling (in terms of providing assured QoS) is still immature because the majority of the existing work is merely based on the characterization of wireless IP traffic without investigating the behavior of queueing systems for such traffic. To overcome such limitations, we investigate SLA parameter negotiation among heterogeneous wireless network operators by focusing on traffic engineering and QoS together for 4G wireless networks. We present a novel mechanism that achieves service continuity through SLA parameter negotiation by using a translation matrix, which maps QoS parameters between different access networks. The SLA matrix composition is modeled analytically based on the G/M/1 queueing system. We evaluate the model using two different scheduling schemes and we derive closed form expressions for different QoS parameters for performance metrics such as packet delay and packet loss rate. We also develop a discrete event simulator and conduct a series of simulation experiments in order to understand the QoS behavior of corresponding traffic classes.     

Multi-service traffic profiles to realise and maintain QoS guarantees in wireless LANs

This paper shows that throughput parameter “bits/s” does not provide accurate insight in load conditions and/or traffic demands in Wireless LANs (WLANs). A multi-service traffic profile that does provide this insight is therefore defined. The multi-service traffic profile is natural to define network resource demands for real-time applications. Simulation results are used to show how to set the traffic profile parameters for elastic traffic. The paper subsequently uses the multi-service profiles to define the notion of a QoS budget. The QoS budget is given to a terminal and the terminal can determine locally if network consumption does not exceed the budget and whether a new network greedy application fits within the QoS budget given. Finally, it is shown how the QoS budget with its multi-service traffic profiles can be used to guarantee quality of service in wireless LANs, in a situation where WLAN channel conditions may vary in time and WLAN stations may move around within a BSS. Simulation results found in literature are used to validate the accuracy of the novel algorithms proposed to guarantee QoS in wireless LANs.     

A Logical Approach to Quality of Service Specification in Video Databases

Quality of Service (QoS) is defined as a set of perceivable attributes expressed in a user-friendly language with parameters that may be objective or subjective. Objective parameters are those related to a particular service and are measurable and verifiable. Subjective parameters are those based on the opinions of the end-users. We believe that quality of service should become an integral part of multimedia database systems and users should be able to query by requiring a quality of service from the system. The specification and enforcement of QoS presents an interesting challenge in multimedia systems development. A deal of effort has been done on QoS specification and control at the system and the network levels, but less work has been done at the application/user level. In this paper, we propose a language, in the style of constraint database languages, for formal specification of QoS constraints. The satisfaction by the system of the user quality requirements can be viewed as a constraint satisfaction problem, and the negotiation can be viewed as constraint optimization. We believe this paper represents a first step towards the development of a database framework for quality of service management in video databases. The contribution of this paper lies in providing a logical framework for specifying and enforcing quality of service in video databases. To our knowledge, this work is the first from a database perspective on quality of service management.     

Integration of pricing with call admission control to meet QoS requirements in cellular networks

Call admission control (CAC) plays a significant role in providing the desired quality of service (QoS) in cellular networks. We investigate the role of pricing as an additional dimension of the call admission control process in order to efficiently and effectively control the use of wireless network resources. First, we prove that, for a given wireless network, there exists a new call arrival rate which can maximize the total utility of users while maintaining the required QoS. Based on this result and observation, we propose an integrated pricing and call admission control scheme where the price is adjusted dynamically based on the current network conditions in order to alleviate the problem of congestion. Our proposed integrated approach implicitly implements a distributed user-based prioritization mechanism by providing negative incentives according to the current network conditions and therefore shaping the aggregate traffic in the network. We compare the performance of our approach in terms of congestion prevention, achievable total user utility, and obtained revenue, with the corresponding results of conventional systems where pricing is not taken into consideration in the call admission control process. These performance results verify the considerable improvement that can be achieved by the integration of pricing in the call admission control process in cellular networks.     

An agent-assisted QoS-based routing algorithm for wireless sensor networks

Existing routing algorithms are not effective in supporting the dynamic characteristics of wireless sensor networks (WSNs) and cannot ensure sufficient quality of service in WSN applications. This paper proposes a novel agent-assisted QoS-based routing algorithm for wireless sensor networks. In the proposed algorithm, the synthetic QoS of WSNs is chosen as the adaptive value of a Particle Swarm Optimization algorithm to improve the overall performance of network. Intelligent software agents are used to monitor changes in network topology, network communication flow, and each node's routing state. These agents can then participate in network routing and network maintenance. Experiment results show that the proposed algorithm can ensure better quality of service in wireless sensor networks compared with traditional algorithms.     

QoS-Aware Admission Control and Dynamic Resource Provisioning Framework in Ubiquitous Multimedia Computing Environments

A ubiquitous service deployment is emerging in the multimedia, networking, and wireless mobile computing area. Therefore, there has been an increasing demand for ubiquitous computing environments to support a certain degree of quality of service (QoS) to meet various service requirements from different computing and networking applications, and to better utilize the computing resources. However, supporting QoS in the ubiquitous computing environments has also raised great concerns regarding the applicability of any QoS solution. Management of such ubiquitous multimedia applications requires new mechanisms, i.e., Soft-QoS framework, to be developed for admission control, negotiation, allocation, and scheduling. In this paper, we present a novel negotiated admission control algorithm that exploits the degradability property of applications to improve the performance of the system. The algorithm is based on setting aside a portion of the resources as reserves and managing it intelligently, so that the total utility of the system can be maximized. The mixed greedy and predictive strategy leads to an efficient protocol that also improves the system performance. We use the constructs of application benefit functions and resource demand functions in the integrated admission control and negotiation protocol. We applied our Soft-QoS framework to the admission controlling and resource scheduling for ubiquitous multimedia devices such as Continuous Media (CM) or Video-On-Demand (VOD) servers, where multimedia applications can generally tolerate certain variations on QoS parameters by providing multiple classes with consistently proportional rather than absolute QoS. Extensive simulation experiments are presented in the paper to evaluate the performance of the novel mechanisms and compare it against some other methods used in the past.This work was in part funded by DARPA through the SPAWARSYSCEN under Contract Number N66001-97-C-8525 and SK Telecom, Korea, under Contract Number (KU-R0405721).     

无线Mesh网络中VOIP的QoS性能分析

针对VoIP(Voice over IP)业务在无线Mesh网上进行传输时存在服务质量(QoS)需求难以保证、带宽利用率低的问题,介绍了VoIP的QoS影响因素,分析了端到端时延、时延抖动和丢包率等几个重要参数,并对VoIP在无线Mesh网中的传输性能进行了论述。提出了基于无线Mesh网络的QoS保证机制,可以为端到端的数据传输公平的分配带宽,并能在保证QoS下实现大规模的实时任务的多跳转发。仿真试验表明能有效降低端到端时延,有着更好的QoS性能。     

基于模糊积分和博弈论的QoS组播路由机制

下一代互联网NGI(next generation Intemet)需要提供服务质量QoS(quality of service)路由能力.由于NGI网络状态难以精确测量与表达,因此,QoS路由基于的信息应该是模糊的.随着网络运营的渐趋商业化,付费上网要求实现QoS计费,而网络提供方与用户的利益冲突要求实现效用双赢.设计了一种基于模糊积分和博弈论的QoS组播路由机制.该机制由边评判、博弈分析和组播路由树建立算法组成,基于模糊积分和适合隶属度函数对边进行模糊综合评判,通过博弈分析确定网络提供方与用户在边上的效用能否达到Nash均衡,通过组播路由树建立算法使得在建立的组播路由树上不仅用户QoS要求得到满足,而且网络提供方效用与用户效用达到或接近Nash均衡下的Pareto最优.仿真结果表明,与QoSMIC等机制相比,该机制具有较好的性能.     

异构无线网络中基于QoS业务感知的信任管理模型

针对异构无线网络中的信任评估问题,提出了一种基于用户QoS感知的信任管理模型。该模型基于异构网络中业务交互及由此产生的用户QoS感知,刻画节点间的信任关系与信任度;并针对QoS感知的主观性和网络欺骗行为,给出了相应的信任策略。理论分析和仿真结果表明:该模型不仅能够有效地完成异构网络环境下的节点信任评估,并能抵御虚假欺骗、振荡服务等恶意行为。     

Quality of Service Support for Multimedia Applications in Third Generation Mobile Networks Using Adaptive Scheduling

Third generation mobile network will support services such as video-telephony, video-conferencing and other multimedia applications. Therefore, this network must provide quality of service (QoS) to these applications consistent with that offered by fixed networks. However, this is a very challenging task due to the instability of the wireless channel and the diverse quality of service requirements dictated by different multimedia applications. In this paper we introduce a resource allocation algorithm for the wireless downlink that takes into account the wireless channel characteristics, the QoS required by the applications as well as a pricing value function. Our solution is based on an adaptive scheduling algorithm originally developed for scheduling real-time processes during transient surges. This algorithm tends to maximize the wireless network operator profit while satisfying the customers' quality requests.     

基于Ad Hoc的QoS多播路由协议研究

近年来,随着计算机网络和无线通信技术的迅速发展,无线移动AdHoc网络在军事和民用方面获得了大量应用。多媒体业务的引入对AdHoc网络提出了多播和QoS服务的需求,如何在AdHoc网络中实现有效的多播和QoS服务是一项十分困难和具有挑战性的工作。论文介绍了当前几种比较典型的QoS多播路由协议,并且从多个方面对它们的特性进行了比较分析,最后对AdHoc网络的QoS多播路由协议的进一步研究提出了预测和展望。     

An Efficient Resource Allocation Mechanism for LTE–GEPON Converged Networks

Optical–wireless convergence is becoming popular as one of the most efficient access network designs that provides quality of service (QoS) guaranteed, uninterrupted, and ubiquitous access to end users. The integration of passive optical networks (PONs) with next-generation wireless access networks is not only a promising integration option but also a cost-effective way of backhauling the next generation wireless access networks. The QoS performance of the PON–wireless converged network can be improved by taking the advantages of the features in both network segments for bandwidth resources management. In this paper, we propose a novel resource allocation mechanism for long term evolution–Gigabit Ethernet PON (LTE–GEPON) converged networks that improves the QoS performance of the converged network. The proposed resource allocation mechanism takes the advantage of the ability to forecast near future packet arrivals in the converged networks. Moreover, it also strategically leverages the inherited features and the frame structures of both the LTE network and GEPON, to manage the available bandwidth resources more efficiently. Using extensive simulations, we show that our proposed resource allocation mechanism improves the delay and jitter performance in the converged network while guarantying the QoS for various next generation broadband services provisioned for both wireless and wired end users. Moreover, we also analyze the dependency between different parameters and the performance of our proposed resource allocations scheme.     

Linux上QoS保证及编程接口的设计

目前的因特网服务并没有提供服务质量（QoS）。随着一些实时的多媒体应用的增加和ATM等具有端到端的服务质量保障的链路技术的出现,需要在IP层上实现QoS的保证。主要讨论Linux的内核中提供的QoS的功能,以及如何在此基础上设计用户编程的接口。     

QoS-TEOS: QoS Guaranteed Throughput-Efficiency Optimal Distributed Scheduling in WiMAX Mesh Networks

WiMAX distributed scheduling can be modeled as two procedures: three-way handshaking procedure and data subframe scheduling procedure. Due to manipulating data transmission directly, data subframe scheduling has a closer relationship with user Quality of Service (QoS) satisfaction, and has more severe impact on network performance, compared with handshaking procedure. A QoS guaranteed Throughput-Efficiency Optimal distributed data subframe Scheduling scheme, named as QoS-TEOS, is proposed. QoS-TEOS achieves QoS guarantee through modeling services into different ranks and assigning them with corresponding priorities. A service with higher priority is scheduled ahead of that with lower priority and offered with high QoS quality. Same kinds of services that request similar QoS quality are classified into one service set. Different service sets are scheduled with different strategies. QoS-TEOS promotes network performance through improving network throughput and efficiency. Theoretical analysis shows that the scheduled data transmission should balance data generation rate from upper layer and transmission rate of physical layer, to avoid network throughput and efficiency declining. Simulation results show that QoS-TEOS works excellently to achieve throughput-efficiency optimization and guarantee a high QoS.     

A Hierarchical Architecture for QoS Guarantees and Routing in Wireless/Mobile Networks

This paper addresses the problem of providing quality of service (QoS) support and routing for wireless networks in the presence of user mobility. The proposed architecture is hierarchical where cells (the basic region of mobile coverage) are organized into QoS/routing domains. The QoS mechanism is based on our earlier work, which follows the integrated services approach with reservation protocol and class-based queueing used for signaling and scheduling, respectively. The routing mechanism proposed in this paper is integrated with the above QoS mechanism and uses a combination of mobile IP, fast route table updates, and proxy address resolution protocol. The architecture and mechanisms have been implemented in a wireless and mobile test bed that uses Lucent WaveLAN cards. Experimental results from this test bed are presented to show the validity of the architecture and to discuss basic system performance.