Theories and models for Internet quality of service

We survey advances in theories and models for Internet quality of service (QoS). We start with the theory of network calculus, which lays the foundation for support of deterministic performance guarantees in networks, and illustrate its applications to integrated services, differentiated services, and streaming media playback delays. We also present mechanisms and architecture for scalable support of guaranteed services in the Internet, based on the concept of a stateless core. Methods for scalable control operations are also discussed. We then turn our attention to statistical performance guarantees and describe several new probabilistic results that can be used for a statistical dimensioning of differentiated services. Lastly, we review proposals and results in supporting performance guarantees in a best effort context. These include models for elastic throughput guarantees based on TCP performance modeling, techniques for some QoS differentiation without access control, and methods that allow an application to control the performance it receives, in the absence of network support     

光业务管理是提供多级别城域网业务的关键

随着电信业的发展，传统的运营商和下一代业务提供商为了获得更多的收入而展开了更激烈的竞争。竞争的加剧又促成了新的业务模型的产生，这些新的模型能使运营商通过降低网络成本将其自身与竞争对手区分开来。未来的业务能力将包括按需分配带宽、基于用户的配置、基于使用的计费以及企业网和专用网的线路外租等等。现在标准组织和系统厂商已经将重点放在了窄带和宽带网络基础设施与下一代互连模型的融合上。尽管这样的技术对于业务提供商实现他们的业务和收入目标是十分必要的，但是，这些技术已经不能再为业务提供商和系统厂商提供足够的竞…     

可在INTERNET网上承载QoS业务的综合服务模型

1 引言 综合服务模型是随着Internet业务及容量不断增加而提出的，它为开发RSVP，RTP协议、处理多媒体/多播业务提供了基本框架，同时也为路由器生产厂商研制开发处理可变负荷的技术提供指南。综合服务模型的前身是D.clark，S.shenker，Lzhang在SIGCOMM92年会上提出的“Supporting Real-time Applicatlons in an Integrated Services Packet Network：Architecture and Mechanisms”。经过几年的发展，综合服务模型已经开始影响路由器及INTERNET的设计，并将在以后的几年中产生更深远的影响。     

Enclaves: enabling secure collaboration over the Internet

The rapid expansion of the Internet means that users increasingly want to interact with each other. Due to the openness and unsecure nature of the Net, users often have to rely on firewalls to protect their connections. Firewalls, however, make real-time interaction and collaboration more difficult. Firewalls are also complicated to configure and expensive to install and maintain, and they are inaccessible to small home offices and mobile users. The Enclaves approach is to transform user machines into “enclaves”, which are protected from outside interference and attacks. Using Enclaves, a group of collaborators can dynamically form a secure virtual subnet within which to conduct their joint business. This paper describes the design and implementation of the Enclaves toolkit and some applications we have built using the toolkit     

A new psychovisual paradigm for image quality assessment: from differentiating distortion types to discriminating quality conditions

This paper investigates the impacts of image quality level on the prediction accuracy of image quality metrics. While many state-of-the-art perceptual image quality assessment methods have achieved fairly well performances in terms of the correlation between the quality predictions and the subjective scores, none of them took into account the effects of the quality levels of those test images on prediction accuracy of the quality metrics. In this work, inspired by the mechanism of human perception under high- and low-quality conditions, we propose a new image quality assessment paradigm based on image quality level classification. Our investigation on TID2008 and other three publicly available databases (LIVE, CSIQ and Toyama-MICT) results in two valuable findings. First, the performances of major well-known image quality assessment methods are significantly affected by image quality level. Second, through combining different quality metrics for different quality levels, superior performance can be achieved as compared to some of the best image quality metrics, e.g., SSIM, MS-SSIM, VIF and VIFP. Experiments and comparative studies are provided to confirm the effectiveness of the proposed new paradigm by differentiating quality levels for image quality assessment.     

COPS-SLS: a service level negotiation protocol for the Internet

The deployment of QoS over the Internet may achieve protocols for the negotiation of service levels, as well as mechanisms for the end-to-end realization of service level agreements. Such general-purpose protocols include Common Open Policy Service (COPS) for policy specification within a domain. This article proposes an extension of the COPS protocol for intra- and interdomain service level negotiation. The proposed protocol is known as COPS-SLS. This allows the configuration of domain policies regarding service levels, and the automatic negotiation of service levels within the domain policies     

Near-sensor image processing: a new paradigm

The paper introduces the concept of near-sensor image processing. By this, the authors mean techniques in which the physical properties of the image sensor itself is utilized to do part of the signal processing task. It is shown that the analog-temporal behavior of photodiodes combined with thresholding amplifiers can be used favorably to do certain low-level image processing tasks including median filtering and convolution. The given examples also show how adaptivity to different light levels can be achieved in a natural way. To extract features from the image, such as moments and shape factors, the authors introduce a simple measurement function.     

光互联网:重画网络蓝图

多业务网络模型的演进过程中,显然一直存在着两种对立的模型,即面向连接的技术（采用带外信令）和无连接的技术。无论哪一种模型都没有试图解决可靠性、可扩展性以及保证提供服务质量（QoS）的基本问题。我们面临的挑战是如何实现动态互动、平滑过渡和分布智能。解决方法和策略一直在变化,其中包括演进的QoS模型、创新的复用技术、综合分组/光的策略,以及不断增加的可扩展性产品,但是每种方法都有其优点和缺点。自从上一世纪90年代末以来,光技术已经大举进入运营商的网络。光学系统能否最终替换分组交换技术？答案似乎很清楚：这些…     

A taxonomy of interaction models for Internet and ATM quality of service architectures

In communication systems there are two worlds at the moment: Internet and ATM. Both possess Quality of Service (QoS) architectures which shall allow them to integrate services of data and telecommunications formerly performed by separate infrastructures. We believe that none of them will be able to oust the other. That means both will exist for at least the middle-term future. Therefore, an interaction between both appears to be necessary, especially in the field of distributed multimedia applications where both worlds meet first. In order to perform gracefully, distributed multimedia applications require a certain QoS provision, in particular from the communication system. Thus, for such applications the existence of heterogeneous IP/ATM networks makes the interaction between Internet and ATM QoS architectures an important issue. In this article a taxonomy of interaction models for the Internet and ATM QoS architectures is developed. We do not let our view be restricted by existing approaches for the interaction between ATM and Internet. Instead we will derive more unconventional models by regarding the possible communication patterns based on different topological variants for heterogeneous IP/ATM networks. The investigation is driven by applications' communication requirements. This is accomplished by examining possibly interacting applications and their communication patterns. The interaction models are contrasted and compared to each other and their assumptions and implications are shown. The derived taxonomy of models allows us to classify proposed approaches for the interaction of Internet and ATM QoS architectures. Thereby we are able to identify the basic assumptions of these approaches and their corresponding restrictions.     

A midterm DBA algorithm for quality of service on aggregation layer EPON networks

This work presents a new approach on dynamic bandwidth allocation (DBA) for Ethernet Passive Optical Networks (EPONs). A brief introduction to the DBA area and major term definitions are given. The related research and standardization efforts are presented. Justification that EPONs can be used on the aggregation network is provided, based on their evolution and related research proposals. Focus is given to the Long Reach-Passive Optical Networks (LR-PONs) and their limitations which show the need for a non-polling, midterm DBA scheme for next-generation EPONs. The challenges arising, because of this new approach, are discussed along with possible solutions. Finally, this work proposes the EMDBA algorithm which is able to overcome the discussed issues. The correct operation of this algorithm is confirmed by a set of simulations using OMNet++ framework, and the outcome results show that EMDBA performance is satisfactory in terms of delay and service differentiation.     

A new quality of service measure for cellular radio systems

A new “quality of service” (QoS) measure called rms excessive blocking, denoted as EB(2), is proposed as a composite measure of the blocking rate and the cell-to-cell variation of blocking rates. EB(2) belongs to a class of measures EB(p),p⩾1, which is unbiased, makes reference to the QoS requirement, is one-sided, and takes on the form of a penalty function. The effectiveness of this rms excessive blocking measure is compared to the conventional mean plus a standard deviation type of measure and evaluated on two efficient dynamic channel-assignment strategies, namely, borrowing with directional channel-locking strategy and compact-pattern (CP)-based dynamic channel assignment (DCA),     

Internet integrated service over ATM: a solution for shortcut QoSvirtual channels

In principle, the interaction of the resource reservation protocol (RSVP) and ATM should allow the IP level to benefit from some features of the ATM layer. The most interesting one is the native support of end-to-end quality of service provided by ATM. On the other hand, there are issues that must be clarified to define correct interworking: for example, the possible overlapping between the mechanisms used in the IP and ATM levels to support QoS, or the needed IP/ATM address resolution mechanism. This article proposes a solution to exploit ATM shortcut VCs supporting QoS in the Internet integrated services model. A straightforward enrichment to the RSVP protocol is defined, which only impacts the devices (hosts and routers) involved in the shortcut procedure. A mechanism for IP/ATM address resolution is provided, avoiding the use of other mechanisms such as NHRP. Special care has been taken to maintain compatibility with “traditional” RSVP hosts and routers     

IDMaps: a global Internet host distance estimation service

There is an increasing need to quickly and efficiently learn network distances, in terms of metrics such as latency or bandwidth, between Internet hosts. For example, Internet content providers often place data and server mirrors throughout the Internet to improve access latency for clients, and it is necessary to direct clients to the nearest mirrors based on some distance metric in order to realize the benefit of the mirrors. We suggest a scalable Internet-wide architecture, called IDMaps, which measures and disseminates distance information on the global Internet. Higher level services can collect such distance information to build a virtual distance map of the Internet and estimate the distance between any pair of IP addresses. We present our solutions to the measurement server placement and distance map construction problems in IDMaps. We show that IDMaps can indeed provide useful distance estimations to applications such as nearest mirror selection     

Cross layer scheme for quality of service aware multicast routing in mobile ad hoc networks

Wireless Networks - A mobile ad-hoc network (MANET) is composed of mobile nodes without any infrastructure where member nodes easily can leave or join the network. This issue provides a dynamic...     

Perceptive animated interfaces: first steps toward a new paradigm for human-computer interaction

This paper presents a vision of the near future in which computer interaction is characterized by natural face-to-face conversations with lifelike characters that speak, emote, and gesture. These animated agents will converse with people much like people converse effectively with assistants in a variety of focused applications. Despite the research advances required to realize this vision, and the lack of strong experimental evidence that animated agents improve human-computer interaction, we argue that initial prototypes of perceptive animated interfaces can be developed today, and that the resulting systems will provide more effective and engaging communication experiences than existing systems. In support of this hypothesis, we first describe initial experiments using an animated character to teach speech and language skills to children with hearing problems, and classroom subjects and social skills to children with autistic spectrum disorder. We then show how existing dialogue system architectures can be transformed into perceptive animated interfaces by integrating computer vision and animation capabilities. We conclude by describing the Colorado Literacy Tutor, a computer-based literacy program that provides an ideal testbed for research and development of perceptive animated interfaces, and consider next steps required to realize the vision.     

ITP: an image transport protocol for the Internet

Images account for a significant and growing fraction of Web downloads. The traditional approach to transporting images uses TCP, but this is overly restrictive for image data. Our analysis shows that the in-order delivery abstraction provided by a TCP-based approach prevents the receiver application from processing and rendering portions of an image when they actually arrive. Thus an image is rendered in bursts interspersed with long idle times rather than smoothly. This paper describes the design, implementation and evaluation of an image transport protocol (ITP) for image transmission over loss-prone congested or wireless networks. ITP improves user-perceived latency using application-level framing (ALF) and out-of-order application data unit (ADU) delivery, achieving significantly better interactive performance as measured by the evolution of peak signal-to-noise ratio (PSNR) with time at the receiver. ITP runs over UDP, incorporates receiver-driven selective reliability, uses a congestion manager (CM) to adapt to network congestion and is customizable for specific image formats (e.g., JPEG and JPEG2000). ITP enables a variety of new receiver post-processing algorithms such as error concealment that further improve the interactivity and responsiveness of reconstructed images. Performance experiments across a variety of loss conditions demonstrate the benefits of ITP in improving the interactivity of image downloads at the receiver