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1.
1.引言 Internet已经延伸到了世界的每一个角落,成为了各种应用的承载工具。在这些应用中,近年不断发展的多媒体应用如视频会议、视频点播(VOD)、VOIP等受到了广泛的关注,这些应用和普通的应用不同,它们对网络带宽、延迟、抖动、丢包率等有一定的要求,因此,网络必须对多媒体应用提供一定的服务质量(QoS)保证。当前的Internet采用的是best-effort(尽力服务)模型。在这个模型中,网络平等地处理所有数据包,尽它的最大努力转发数据包,其首要目标是实现对链路的统计复用以达到高网络利用率,路由器作为核心设备,它是无状态的,也就是说它  相似文献   

2.
《Computer Networks》2000,32(2):185-209
This paper presents a Differentiated Services (Diffserv or DS) architecture for multimedia streaming applications. Specifically, we define two types of services in the context of Assured Forwarding (AF) per hop behavior (PHB) that are differentiated in terms of reliability of packet delivery: the High Reliable (HR) service and the Less Assured (LA) service. We propose a novel node mechanism called Selective Pushout with Random Early Detection (SPRED) that is capable of simultaneously achieving the following four objectives: (1) a core router does not maintain any state information for each flow (i.e., core-stateless); (2) the packet sequence within each flow is not re-ordered at a node; (3) packets from HR service are delivered more reliably than packets from LA service at a node during congestion; and (4) packets from TCP traffic are dropped randomly to avoid global synchronization during congestion. We show that SPRED is a generalized buffer management algorithm of both tail-dropping and Random Early Detection (RED), and combines the best features of pushout (PO), RED and RED with In/Out (RIO) mechanisms. Simulation results demonstrate that under the same link speed and network topology, network nodes employing our Diffserv architecture have substantial performance improvement over the current Best Effort (BE) Internet architecture for multimedia streaming applications.  相似文献   

3.
Advances in networks during the past decades have fostered the deployment of a variety of Internet applications. Many of these applications have a range of Quality-of-Service (QoS) requirements, some involving network throughput, delay, and reliability. Consequently, there is growing need for network services that can differentiate applications having QoS requirements from those without and to be able to further classify applications with QoS requirements into different classes at the IP-network level. The Internet Engineering Task Force (IETF) has proposed Differentiated Services (DiffServ) to provide QoS in IP-based networks. The goal of DiffServ is to define configurable types of packet forwarding that can provide service differentiation for large aggregates of network traffic. We report on our investigation of Relative Proportional Differentiated Services to implement DiffServ in IP-based networks and one that supports the provisioning and management of QoS for Internet Applications. The main contributions of the paper are the introduction of a novel traffic conditioning architecture for the marker and shaper/policer which relies on feedback from a metering component, and the provision for a QoS manager to enable a network administrator or a management application to dynamically adjust control parameters.  相似文献   

4.
基于MPLS的区分服务技术   总被引:1,自引:0,他引:1  
传统的Internet只能提供尽力传送服务,但这种没有任何保证、不可预测的服务已不能满足许多应用的需要。IETF提出的Intserv/RSVP方案从技术角度可以提供灵活的服务质量,满足各种应用的需要,但该方案要求每个路由器保存每个连接的状态,复杂化了核心路由器的处理,因此实现 和配置是非常困难的。IETF提出的Diffserv将各种复杂的接入控制、每个连接的管理交给边界路由器处理,核心路由器只处理流量聚合,因而具有更好的伸缩性和鲁棒性。MPLS是一种可以在多种第二层媒质上进行标签交换的网络技术,将探讨如何结合Diffserv和MPLS两种技术,提供各种服务质量,特别是VPN。  相似文献   

5.
The differentiated services architecture (Diffserv) enables service providers to offer tighter, more comprehensive service-level agreements (SLAs) for IP service performance. One way it does this is by letting designers engineer IP backbone networks to assure that SLA parameters are met on a per-class basis. This review covers best practices for designing, validating, deploying, and operating Diffserv in the network backbone. It also presents new results from router-based testing that demonstrate how, with Diffserv, high-performance backbone routers can achieve tight SLA capabilities.  相似文献   

6.
随着互联网应用的增长,目前提供尽力服务的互联网体系结构越来越不能满足这些新的服务要求。通过设计出一种新的路由器缓冲区管理策略,探讨一种基于分类服务的新一代互联网体系结构的实现方式。  相似文献   

7.
The evolution of computer networks has experienced several major steps, and research focus of each step has been kept changing and evolving, from ARPANET to OSI/RM, then HSN (high speed network) and HPN (high performance network). During the evolution, computer networks represented by Internet have made great progress and gained unprecedented success. However, with the appearance and intensification of tussle, along with the three difficult problems (service customizing, resource control and user management) of modern network, it is found that traditional Internet and its architecture no longer meet the requirements of next generation network. Therefore, it is the next generation network that current Internet must evolve to. With the mindset of achieving valuable guidance for research on next generation network, this paper firstly analyzes some dilemmas facing current Internet and its architecture, and then surveys some recent influential research work and progresses in computer networks and related areas, including new generation network architecture, network resource control technologies, network management and security, distributed computing and middleware, wireless/mobile network, new generation network services and applications, and foundational theories on network modeling. Finally, this paper concludes that within the research on next generation network, more attention should be paid to the high availability network and corresponding architecture, key theories and supporting technologies.  相似文献   

8.
It is widely common that mobile applications collect non-critical personally identifiable information(PII)from users'devices to the cloud by application service providers(ASPs)in a positive manner to provide precise and recommending services.Meanwhile,Internet service providers(ISPs)or local network providers also have strong requirements to collect PIIs for finer-grained traffic control and security services.However,it is a challenge to locate PIIs accurately in the massive data of network traffic just like looking a needle in a haystack.In this paper,we address this challenge by presenting an efficient and light-weight approach,namely TPII,which can locate and track PIIs from the HTTP layer rebuilt from raw network traffics.This approach only collects three features from HTTP fields as users'behaviors and then establishes a tree-based decision model to dig PIIs efficiently and accurately.Without any priori knowledge,TPII can identify any types of PIIs from any mobile applications,which has a broad vision of applications.We evaluate the proposed approach on a real dataset collected from a campus network with more than 13k users.The experimental results show that the precision and recall of TPII are 91.72%and 94.51%respectively and a parallel implementation of TPII can achieve 213 million records digging and labelling within one hour,reaching near to support 1Gbps wirespeed inspection in practice.Our approach provides network service providers a practical way to collect PIIs for better services.  相似文献   

9.
Medical services have been rapidly changing from traditional through clinics and institutions and focusing on dealing with a quiet driving method. Some innovative development contributed to the rapid changes in the pharmaceutical vertical. In a variety of technological innovations, in response to progress, that goal can communicate customization and remote healthcare management. Now, health care is developing a wide range of medical applications, leveraging existing progressive organizations and other 4G forced continuously to respond to the future requirements of sensible medical applications. With the growth of a brilliant medical service market, using an interface with the tissue produces a change in the size and location information. It complexes requirements in the organization and the transmission speed between the information rate and different lazy elements. The development of the market for these sensitive medical services, large-scale, needs to communicate with many types of machines required in clinic-based applications gadgets and machinery sensors availability requirements. Further, when used, e.g., for medical procedures and the distance haptic Internet reliability and low latency requirements or super-critical. Existing innovation response the meet the demanding and dynamic needs of different smart medical applications placed on the network response. Therefore, up 5G network provides savvy to help, for example, be able to meet most of ultra-low lazy, essentials of high data transmission, ultra-reliability, high thickness and high energy efficiency of medical service applications. The future savvy medical network will be required to be a fusion of things and gadgets rely on incremental 5G cell inclusion, network implementation and solve problems related to security. This article gives things smart and 5G and provides medical classification, research models, difficulties, and future exploration bearing class best.  相似文献   

10.
This paper explores networking issues that arise as a result of the operational requirements of future applications of small unmanned aircraft systems. Small unmanned aircraft systems have the potential to create new applications and markets in civil domains, enable many disruptive technologies, and put considerable stress on air traffic control systems. The operational requirements lead to networking requirements that are mapped to three different conceptual axes that include network connectivity, data delivery, and service discovery. The location of small UAS networking requirements and limitations along these axes has implications on the networking architectures that should be deployed. The delay-tolerant mobile ad-hoc network architecture offers the best option in terms of flexibility, reliability, robustness, and performance compared to other possibilities. This network architecture also provides the opportunity to exploit controlled mobility to improve performance when the network becomes stressed or fractured.  相似文献   

11.
张澄海  路云 《计算机工程》2003,29(16):114-116
随着Internet及网络经济的快速发展,企业在网络的安全性等方面提出了更高的要求,虚拟专用网(VPN)以其安全性好、成本低等优势赢得了越来越多企业的青睐。IP层安全协议(IPSec)能很好地实现VPN。但是基于IPsec的VPN的网络服务质量不能满足用户的需求。针对此问题,文章提出了用区分服务(DiffServ)来实现IPSec隧道的服务质量保障的方案,这样IPSec隧道就可以根据不同的需求提供不同的网络性能。文章深入研究了区分服务和IPSec隧道技术,通过实验进一步证明了该方案的可行性和优势。  相似文献   

12.
Internet区分服务及其几个热点问题的研究   总被引:89,自引:2,他引:87  
综述了Internet在区分服务(Differentiated services,Diffserv)研究方面的一些最新的工作,分析了Diffserv的体系结构、Diffserv的典型服务与技术,并着重论述了Internet Diffserv所面临的问题,包括Diffserv与综合服务(Integrated services,Intserv)相结合的端到端服务质量(QoS)提供机制、Diffserv  相似文献   

13.
WEBGOP is a programming architecture for collaborative Web services using graph-oriented programming. The motivation for the project comes from the realization that the integration of collaborative Web services lacks support. The aim of WEBGOP is to extend the Web from a client-server system to a structured multipoint system. A graph abstraction of the network provides the structure for the integration of Web services and facilitates their configuration and programming. Using WEBGOP, a logical graph representing a virtual-overlay network over the Internet is created to link up collaborative Web services. Web services are individually or jointly invoked through either unicast or multicast messages within the overlay network. All messages are based on the simple-object access protocol (SOAP). This forms an extension of the hypertext transfer protocol (HTTP) to support the distributed invocation of Web services. The Web services on different servers work collaboratively for a multipoint network application. This project provides a structured integration of Web services by extending the support of intermediary processing in a multipoint service. It also provides a rich network-programming interface for a new class of integrated Web applications while retaining the use of the Internet protocol and HTTP.  相似文献   

14.
Scattercast: an adaptable broadcast distribution framework   总被引:5,自引:0,他引:5  
Internet broadcasting - the simultaneous distribution of live content streams to a large audience - has a number of interesting applications ranging from real-time broadcasts of audio/video streams for online concerts or sporting events to efficient and reliable large-scale software distribution. We identify three fundamental requirements for scalable broadcasting services: an efficient infrastructure for large-scale broadcasting, an ability to adapt the infrastructure to suit the requirements of a wide range of applications, and ease of deployment of the infrastructure. Although solutions such as the network-layer IP multicast approach and a slew of overlay distribution networks exist today, none of these technologies satisfactorily addresses all of the above concerns. In this paper, we argue that an application-customizable hybrid overlay is well suited to meet these challenges. To this end, we propose an architecture called scattercast that relies on a network of strategically located agents called ScatterCast proXies or SCXs. These agents collaboratively provide the broadcast service for a session. Clients locate a nearby SCX and tap into the session via that SCX. Scattercast constructs a hybrid overlay network composed of unicast links between SCXs that interconnect locally scoped multicast regions. Rather than define a single standardized service model for transmitting data on top of the overlay, scattercast builds a customizable transport framework that provides adaptability by leveraging application-defined semantics to drive the distribution of content. We demonstrate the ability of our architecture to provide efficient distribution via a set of simulation experiments. Finally, we present our experience with the adaptability of the framework by describing two applications, a real-time Internet radio and an online slide-presentation tool, both of which we have built on top of a prototype implementation of the architecture.Received: 15 March 2002, Accepted: 2 October 2002,  相似文献   

15.
The current Internet can only provide the best-effort services. By growing the Internet and its applications, new services with different requirements are developed. The differentiated services (Diffserv) [S. Blake, M. Carlson, E. Davies, Z. Wang, W. Weiss, An Architecture for Differentiated Services, IETF RFC 2475, 1998; K. Nichols, V. Jacobson, L. Zhang, A Two-bit Differentiated Services Architecture for the Internet, IETF RFC 2638, July 1999; T. Li, Y. Rekhter, A Provider Architecture for Differentiated Services and Traffic Engineering (PASTE), IETF RFC 2430, October 1998] is a scalable model for providing end-to-end quality of services. A Diffserv router consists of different components including classifier, meter, marker, dropper, shaper and scheduler. In this paper, we use the benefits of the fuzzy logic controller to design a fuzzy based traffic conditioner for Internet differentiated services. Our proposed model consists of three major parts: a fuzzy meter/marker (FM), a fuzzy active queue management (FAQM) algorithm and a fuzzy scheduler (FS). The proposed FM used to measure and mark the input traffic is based on the single rate three colors meter (srTCM) mechanism [J. Heinane, et al., A Single Rate Three Color Marker, RFC 2697, September 1999]. The FM meters an IP packet stream and marks its packets GREEN, YELLOW, or RED. The proposed FAQM is a fuzzy implementation of the well-known BLUE active queue management (AQM) algorithm [W. Feng, D. Kandlur, D. Saha, K. Shin, BLUE: A New Class of Active Queue Management Algorithms U. Michigan CSE-TR-387-99, April 1999]. To achieve a good throughput and reasonable packet loss ratio, the proposed FAQM mechanism employs a fuzzy logic controller. The third part of the proposed fuzzy traffic conditioner is FS. It is based on the traditional weighted fair queue (WFQ) mechanism [A. Demers, S. Keshav, S. Shenker, Analysis and simulation of a fair queueing algorithm, in: SIGCOMM Symposium on Communications Architectures and Protocols, Austin, Texas, September 1989, pp. 1–12] that tunes the weight of each queue by a fuzzy logic controller. To evaluate the performance of the proposed model, we developed a software in C++ environment to simulate it. Different network topologies with different traffic parameters were performed. The simulation results easily helped us to judge the merit of the proposed FM, FAQM and FS because of their remarkable performance over the traditional non-fuzzy mechanisms.  相似文献   

16.
The ubiquity of the Internet and various intranets has brought about widespread availability of online services and applications accessible through the network. Cluster-based network services have been rapidly emerging due to their cost-effectiveness in achieving high availability and incremental scalability. We present the design and implementation of the Neptune middleware system that provides clustering support and replication management for scalable network services. Neptune employs a loosely connected and functionally symmetric clustering architecture to achieve high scalability and robustness. It shields the clustering complexities from application developers through simple programming interfaces. In addition, Neptune provides replication management with flexible replication consistency support at the clustering middleware level. Such support can be easily applied to a large number of applications with different underlying data management mechanisms or service semantics. The system has been implemented on Linux and Solaris clusters, where a number of applications have been successfully deployed. Our evaluations demonstrate the system performance and smooth failure recovery achieved by proposed techniques.  相似文献   

17.
While the Internet is successful in supporting traditional data-only traffic, an integrated services Internet is inevitable with the emergence of new applications such as voice, video, multimedia, and interactive video conferencing. Such an integrated services network should support a wide range of applications with diverse quality of service requirements and traffic characteristics. Provision for quality of service in packet networks in general, and in the Internet in particular, is the focus of most of the recent developments in switching and routing system design. We designed a generic, single-queue scheduler engine for use in a programmable packet switch/router to handle IP packets, ATM cells, or a combination of both. Comprising 275,000 gates, the 0.35-micron ASIC is incorporated into a prototype programmable packet switch  相似文献   

18.
当前的互联网只能提供“尽力而为”的发送服务,使网络层无法控制传输质量,因此,为不同应用提供不同QoS的服务是网络用户的基本要求和互联网面临的重要研究课题。近几年,有关IP QoS的讨论焦点是Intserv、Diffserv、MPLS等服务模型和框架,在资源受限的网络环境下,这些解决方案实现的基础是QoS路由。论文的目的是在明确QoS路由重要性的基础上,通过建立网络模型和度量合成规则,详细分析单播和多播可能遇到的单度量的基本路由问题和多度量的组合路由问题,并给出解决这些路由问题的方法和计算复杂度,这对于设计和实现可行的QoS路由协议或算法有一定参考价值。  相似文献   

19.
为满足现代高带宽互联网应用环境中的安全性保障要求,提出了一种基于Tilera GX36多核网络处理平台的IPSec VPN系统结构,利用SDN思想设计了系统控制面和数据面的程序功能模块,实现网络流量安全的灵活控制。针对系统中安全策略检索性能要求,提出一种基于Hash的三级安全策略流表存储结构,并以各Tile CPU缓存中的安全关联流表为快速检索数据源设计一种安全策略检索方法。测试结果表明,对于互联网中典型的小包、中包和大包应用场景,该系统均能达到近40 Gb/s的处理性能。  相似文献   

20.
Video surveillance systems are playing an important role to protect lives and assets of individuals, enterprises and governments. Due to the prevalence of wired and wireless access to Internet, it would be a trend to integrate present isolated video surveillance systems by applying distributed computing environment and to further gestate diversified multimedia intelligent surveillance (MIS) applications in ubiquity. In this paper, we propose a distributed and secure architecture for ubiquitous video surveillance (UVS) services over Internet and error-prone wireless networks with scalability, ubiquity and privacy. As cloud computing, users consume UVS related resources as a service and do not need to own the physical infrastructure, platform, or software. To protect the service privacy, preserve the service scalability and provide reliable UVS video streaming for end users, we apply the AES security mechanism, multicast overlay network and forward error correction (FEC), respectively. Different value-added services can be created and added to this architecture without introducing much traffic load and degrading service quality. Besides, we construct an experimental test-bed for UVS system with three kinds of services to detect fire and fall-incident features and record the captured video at the same time. Experimental results showed that the proposed distributed service architecture is effective and numbers of services on different multicast islands were successfully connected without influencing the playback quality. The average sending rate and the receiving rates of these services are quite similar, and the surveillance video is smoothly played.  相似文献   

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