DiffServ Model Research Articles

QoS Guarantee Framework of English Literature Course Online System Based on Concurrent Optimization Network Environment

First, the initial connection isolation method ICS is established to separate false connections generated by malicious network behaviors from normal established connections, and form a controllable initial connection table. A strategy combining extended RSVP protocol and DiffServ model is designed to ensure the realization of QoS in large campus network. The simulation test results show that the application of this model can effectively improve the QoS of large-scale campus networks, and the problems that need to be paid attention to when running the parallel operation of the database management system correctly in the network environment. Especially to prevent data corruption and loss when developing multi-user systems.

An on demand load balancing multi-path routing protocol for differentiated services in MWSN

As an important part of the Internet of Things, mobile wireless sensor network (MWSN) will generate traffic with different service quality requirements due to the multi-sensor integration of nodes and application diversity. Due to the topological changes, resource constraints and self-organizing characteristics of MWSN, the Per-Hop Behavior (PHB) approach in the traditional Diff-Serv model has many challenges in providing differential service. In this paper, a path reservation multipath routing (PRMR) protocol is proposed, which can provide a suitable path for each type of traffic with service requirements. PRMR protocol includes path discovery algorithm and packet scheduling algorithm. In addition, the path scheduling model and scheduling algorithm in PRMR solve the problem of load imbalance among reserved paths caused by different types of traffic. In scenarios with different number of nodes, three types of traffic, integrity sensitive data, delay sensitive data and normal data, are used to verify the performance of PRMR differential service and load balancing. Simulation experiments not only compare the quality of service provided by each reserved path in PRMR, but also compare the differential service performance between PRMR and several multipath routing algorithms. Simulation results show that PRMR routing algorithm can guarantee high packet delivery rate and low delay for integrity-sensitive data and delay-sensitive data, respectively. In addition, the simulation results of the average residual energy index show that the protocol can achieve network energy balance.

Joint Task Offloading and Resource Allocation Strategy for DiffServ in Vehicular Cloud System

A vehicular cloud (VC) can reduce latency and improve resource utilization of the Internet of vehicles by effectively using the underutilized computing resources of nearby vehicles. Although the task offloading of the VC enhances road safety and traffic management on the Internet of vehicles and meets the low-latency requirements for driving safety services on the Internet of vehicles business, there are still some key challenges such as the resource allocation mechanism of differentiated services (DiffServ) and task offloading mechanism of improving user experience. To address these issues, we study the task offloading and resource allocation strategy of the VC system where tasks generated by vehicles can be offloaded and executed cooperatively by vehicles in VC. Specifically, the computing task is further divided into independent subtasks and executed in different vehicles in VC to maximize the offloading utility. Considering the mobility of vehicles, the deadline of tasks, and the limited computing resources, we propose the optimization problem of task offloading in the VC system in the cause of improved user experience. To characterize the difference in service requirements resulting from the diversity of tasks, a DiffServ model focusing on the pricing of a task is utilized. The initial pricing of a task is tailored by the characteristics of the task and the uniqueness of the network status. In this model, tasks are sorted and processed in order according to task pricing, so as to optimize resource allocation. Numerical results show that the proposed scheme can effectively increase the resource utilization and task completion ratio.

DIFFSERV BASED QOS PERFORMANCE STUDY OF VIDEO CONFERENCING APPLICATION USING TRADITIONAL IP AND MPLS-TE NETWORKS OVER IPV4 AND IPV6

With the constant evolution in the communication industry and development in the network technology, demand for more sophisticated and quality assured multimedia applications has increased. Although Differentiated Services (DiffServ) model can be deployed over the traditional Internet Protocol (IP) based networks to ensure QoS, it is unable to provide a guaranteed end-to-end QoS to the network. Multiprotocol Label Switching (MPLS) is one of the recent technologies that is being used as a backbone network to provide QoS on account of its Traffic Engineering (TE) capabilities. Use of DiffServ as the dedicated QoS model over MPLS-TE networks can lead to a significant improvement in the quality of the services provided by the network. IPv4 is the basic network layer protocol currently in use over the Internet. With technological advances and increase in number of users and their requirements, IPv4 is proving to be insufficient. IPv6 is the latest version of the Internet Protocol that can potentially takeover as the basic network layer protocol. In this paper, an attempt has been made to study and improve the QoS performance of the video conferencing application by using DiffServ-aware MPLS-TE network. Comparison of delay, jitter, packet loss and throughput as QoS parameters has been done over the network using IPv4 and IPv6. It has been seen that MPLS-TE networks show an improved performance as compared to traditional IP networks, with a further upgrade in performance over IPv6.

Differentiated forwarding and caching in named-data networking

Named-data networking (NDN) is designed to provide scalable and efficient content delivery, particularly for reducing redundant data transmission. To make the usefulness of NDN more widespread, however, it should support various types of traffic and their quality of Service (QoS) requirements. In this paper, we propose a differentiated services (diffserv) model for NDN. For scalability, the proposed diffserv model is designed to follow the guidelines from the diffserv model in the current Internet. Traffic classification and packet marking are performed at edge routers, and class-based service differentiation is provided by core routers. The proposed model is also considered to take the advantages of NDN unique features such as interest aggregation and in-network caching. We implement our model on the NDN module in ns3, and show the effectiveness of NDN diffserv through extensive simulations.

Ipv6中利用汇聚数据流实现QoS的新机制

本文通过对IntServ模型、DiffServ模型和MPLS模型分析，汲取了它们思想精髓，将同一子网发向同一目的子网的所有数据流聚集成类，以类为单位进行资源申请，在满足QoS要求的链路上建立虚电路，直到该类中所有的Ipv6分组都发送完后，取消虚电路。这种方法既保证数据的QoS要求，也减少了资源申请的次数；降低网络成本，适合在大型网络中应用。This article has analyzed the IntServ model, DiffServ model and MPLS model, and it absorbs their essence. All data flows from the same subnet to the same destination subnet will be gathered into a class. The class is acted as the unit of resource application, and the virtual circuit is established in the link meeting the QoS requirements; the virtual circuit is canceled until all the Ipv6 packets have been sent. This method not only guarantees the QoS requirements of data, but also reduces the number of the application resources; it has reduced the network cost suiting for the application in large-scale networks.

Performance evaluation of selected Transmission Control Protocol variants over a digital video broadcasting‐second generation broadband satellite multimedia system with QoS

SUMMARYThis paper presents an analysis of several Transmission Control Protocol (TCP) variants working over a digital video broadcasting‐second generation (DVB‐S2) satellite link with the support of the Differentiated Services (DiffServ) architecture to provide quality of service (QoS). This analysis is carried out using the NS‐2 simulator tool. Three TCP variants are considered: SACK TCP, Hybla TCP, and CUBIC TCP. These TCP variants are taken as a starting point because they have proven to be the most suitable variants to deal with long delays present in satellite links. The DVB‐S2 link also introduces the challenge of dealing with variable bandwidth, whereas the DiffServ architecture introduces the challenge of dealing with different priorities. In this paper, we propose a DiffServ model that includes a modified queuing mechanism to enhance the goodput of the assured forwarding traffic class. This modified DiffServ model is simulated and tested, considering the interaction of the selected TCP variants. In addition, we present evaluation metrics, significant simulations results, and conclusions about the performance of these TCP variants evaluated over the proposed scenario. As a general conclusion, we show that CUBIC TCP is the TCP variant that shows the best performance in terms of goodput, latency, and friendliness. Copyright © 2012 John Wiley & Sons, Ltd.

Realization of QoS Control Strategies in the next Generation Network on the Basis of Differentiated Service Model and Priority of Inter-Frame

With the development of networks and wideband technology, Next Generation Network (NGN) evolves into integrated transmission network of the multimedia information which including data, voice, image, the real-time tasks, etc. The traditional IP network provides only "best-effort" service and cannot meet the needs of multi-media applications and the different demands of a variety of users for network transmission quality. On the basis of a detailed analysis to Differentiated service (DiffServ) model and the characteristics of MPEG-4 encoding, the QoS control strategy of video streaming in NGN is proposed. That is a QoS control strategy which uses priority of Inter-Frame combining with DiffServ model in network congestion. Simulation and testing results show that the strategy can improve the transmission quality of the video stream effectively in the case of limited bandwidth.

Toward statistical QoS guarantees in a differentiated services network

In this paper, we propose and analyze a methodology for providing statistical guarantees within the diffserv model in a network, which uses static-priority schedulers. We extend the previous work on statistical delay analysis and develop a method that can be used to derive delay bounds without specific information on flow population. With this new method, we are able to successfully employ a utilization-based admission control approach for flow admission. This approach does not require explicit delay computation at admission time and hence is scalable to large systems. We systematically analyze the performance of our approaches in terms of system utilization. As expected, our experimental data show that statistical services can achieve much higher utilization than deterministic services.

A Distributed DiffServ Supporting Scheduling Algorithm

PDF HTML阅读 XML下载 导出引用 引用提醒 一种支持DiffServ模型的全分布式调度算法 DOI: 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: Supported by the National Natural Science Foundation of China under Grant No.60572042 (国家自然科学基金); the National High-Tech Research and Development Plan of China under Grant No.2005AA121210 (国家高技术研究发展计划(863)); the National Basic Research Program of China under Grant No.2007CB307102 (国家重点基础研究发展计划(973)) A Distributed DiffServ Supporting Scheduling Algorithm Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:调度算法设计对于网络路由设备实现区分服务(DiffServ)模型的单跳行为(per hop behavior,简称PHB)至关重要.现有支持DiffServ模型的调度算法普遍基于输出排队(output queued,简称OQ)或是输入排队(input queued,简称IQ)交换结构进行设计,均无法在高速环境下提供高性能的调度.基于联合输入/交叉节点排队(combined input-crosspoint-queued,简称CICQ)交换结构提出一种支持DiffServ模型的全分布式调度算法DDSS (distributed DiffServ supporting scheduling),并通过理论分析对其公平性进行了验证.DDSS算法采用基于预约带宽的逐级流量控制机制实现所有预约带宽在快速转发(expedited forwarding,简称EF)业务与确保转发(assured forwarding,简称AF)业务之间的分配,采用优先级调度机制为EF业务提供低延迟服务,算法复杂度为O(log N).仿真结果表明,DDSS算法具有良好的时延性能和公平特性,与现有算法相比,能够更好地支持DiffServ模型. Abstract:Scheduling algorithm is very important for network design to implement per hop behaviors (PHBs) in DiffServ model. Most of the presented DiffServ supporting scheduling algorithms are based on output queued (OQ) switches or input queued (IQ) switches, which are not suitable to be used in high speed network. This paper proposes a distributed DiffServ supporting scheduling (DDSS) algorithm based on combined input-crosspoint -queued (CICQ) switches. Theoretical analysis illuminates that the DDSS algorithm can obtain good fairness. The DDSS algorithm adopts a two-stage flow control mechanism based on periodic statistic to achieve fair bandwidth allocation for expedited forwarding (EF) and assured forwarding (AF) traffic, and uses a priority scheduling mechanism to provide lower delay for EF traffic. The time complexity of the DDSS algorithm is only O(log N), hence is practical and scalable for high speed network. Simulation results show that DDSS algorithm can obtain good fairness and delay performance. It is more appropriate to be used to support the DiffServ model. 参考文献 相似文献 引证文献

EVALUATION OF QOS IN UMTS BACKBONE NETWORK BY USING DIFFERENTIATED SERVICES

A distinguishing feature of the Universal Mobile Telecommunications System (UMTS) is the support of different levels of quality of service (QoS) as required by subscribers and their applications. To provide QoS, the UMTS backbone network needs an efficient QoS mechanism to provide the demanded level of services on UMTS network. We implement a model to investigate end-to-end quality of service (QoS) provisioning approaches for UMTS networks in a DiffServ IP network environment. The effort was put on QoS classes mapping from DiffServ to UMTS, Access Control, buffering and scheduling optimization. The DiffServ Code Point was utilized in the E2E UMTS QoS provisioning to differentiate different types of traffic. We hybridized our work by applying Resource reservation protocol (RSVP) in routers and hosts. The main advantages and drawbacks are discussed. We found that our proposed model (hybridized model (DiffServ/RSVP)) improves the end-to-end delay and end-to-end variation compared with DiffServ model only, and it is superior to DiffServ regarding to throughput, utilization and packet loss ratio. The overall work guarantees the E2E QoS parameters of each service class, especially for real-time applications and improved the bandwidth utilization. Simulation results show that DiffServ can be an effective candidate for UMTS backbone bearer service.

Enhancement of fairness in a DiffServ network using a novel queuing algorithm

Core-Stateless Fair Queuing (CSFQ) algorithm was proposed to allocate bandwidth fairly at routers in the Differentiated Services Model (DiffServ Model). However, CSFQ can not effectively provide the fairness between TCP connections and UDP connections. Besides, the setting of buffer size strongly affects the efficiency of CSFQ. In this paper, we present a novel CSFQ-based queuing algorithm. Based on the estimated value of fair share, the probability to drop packet is determined to ensure fair share of bandwidth. The simulated experimental results demonstrate that the proposed scheme outperforms CSFQ.

Fair early drop marker for improving TCP fairness in multiple domain DiffServ networks

The differentiated services (DiffServ) model, proposed as a scalable way of providing quality of service in the Internet, provides packet level service differentiation on a per-hop basis. To provide the end-to-end service differentiation more efficiently for the assured services, as well as a source marker, an interdomain marker placed at the boundary edge routers connecting network domains is necessary because an Internet connection usually spans through a path involving one or more network domains. Such an interdomain marker should be operated at the aggregate flow level due to the scalability problem. The random early demotion and promotion (REDP) marker was proposed as an interdomain marker. It introduces randomness and early decisions on the three-color packet marking process at the aggregate flow level to remove the phase effect that brings about the unfairness in the demotion and promotion among different flows. The REDP marker achieves good UDP fairness in demoting and promoting packets through random and early marking decisions on packets. However, TCP fairness of the REDP marker is not obvious as for UDP sources. In this paper, we propose a new interdomain marker to resolve the problem of the REDP marker. Instead of unfair packet droppings at the RIO buffers in the core routers which cause unfairness of TCP flows, it fairly drops the green packets of each TCP flow with a token filling rate configuration method before they enter into the core routers. By doing this fair early packet dropping, it increases TCP fairness at a minor expense for the total throughput.

Towards all-IP wireless networks: architectures and resource management mechanism

Future wireless internet will consist of different wireless technologies that should operate together in an efficient way to provide seamless connectivity to mobile users. The integration of different networks and technologies is a challenging problem mainly because of the heterogeneity in access technologies, network architectures, protocols and service demands. Firstly, this paper discusses three architectures for an all-IP network integrating different wireless technologies using IP and its associated service models. The first architecture, called ISB, is based on a combination of Differentiated Services (DiffServ) and Integrated Services (IntServ) models appropriate for low-bandwidth 3G cellular networks with significant resource management capabilities. The second architecture, called DSB, is purely based on the DiffServ model targeted for high-bandwidth wireless LANs with little resource management capabilities. The last architecture, called AIP, combines ISB and DSB architectures to facilitate the integration of wireless LAN and 3G cellular networks towards a uniform architecture for all-IP wireless networks. Secondly, this paper proposes a flexible hierarchical resource management mechanism for the proposed All-IP Architecture (AIP) which aims at providing connection-level Quality of Service (QoS) for mobile users. Simulation results show that the proposed mechanism satisfies the hard constraint on connection dropping probability while maintaining a high-bandwidth utilisation.

Distributed QoS Scheme for Multimedia Communication in Mobile Ad Hoc Network

In this paper we present a network layer based admission control and simple class based service differentiation model to support QoS in mobile ad hoc network. Our distributed admission control procedure works along with the route finding phase of reactive routing protocols for mobile ad hoc network (AODV, DSR etc). We also propose a simple class based distributed service differentiation system to support QoS once a traffic is admitted by our admission control mechanism. The proposed service differentiation is based on DiffServ model and includes modifications like configuration of each node with edge and core functionality, dynamic selection of edge/core functionality, use of minimal and simple classes. Simulation results show that our system allows seven times more real time traffic in the network than the proposed QoS for AODV model while satisfying the demanded end-to-end delay and providing low jitter.

Fair intelligent admission control over resource-feedback DiffServ network

The basic DiffServ model lacks mechanisms to prevent itself from being overloaded and to inform its internal capability to the external world. This paper addresses the problem by presenting a Fair Intelligent Admission Control (FIAC) over an enhanced-DiffServ architecture. The central idea is to make admission decision based on both informed internal network QoS states and the external traffic QoS requirements at the edge node. This model has several advantages: (1) it is backward compatible with DiffServ, (2) it adapts to traffic load and network QoS state changes, and (3) it provides interactive communication between the external QoS requirements and the internal DiffServ network capability. In this paper, we use simulation to evaluate the performance of DiffServ with or without FIAC. The performance demonstrates that the new scheme is able to admit traffic fairly and achieve edge-to-edge QoS under heavy traffic conditions and network state changes.

Experiments with equivalent differentiated services in a grid context

Grids generally rely on a complex interconnection of Internet Protocol (IP) domains that offer heterogeneous services and unpredictable performance characteristics, particularly at the local area network/wide area network boundary. The total lack of end-to-end resource control in IP networks is responsible for performance problems that may affect the whole Grid environment. An end-to-end service differentiation architecture that controls heterogeneous communication performance is thus needed. We propose the Equivalent Differentiated Services (EDS) architecture, based on a layer-4 service differentiation solution exploiting a new layer-3 relative DiffServ model. In this paper, we present the EDS packet forwarding principles, the router mechanisms and two adaptive packet marking algorithms. As a proof of concept, we have implemented the EDS architecture in Linux and performed experiments on a transoceanic testbed.

Efficient resource allocation for China's 3G/4G wireless networks

The all-IP DiffServ model is expected to be the most promising architecture for QoS provisioning in China's next-generation wireless networks, due to its scalability, convenience for mobility support, and capability of interworking heterogeneous radio access networks. This article focuses on efficient resource allocation in a wireless DiffServ architecture. Resource utilization efficiency is particularly important for China's wireless networks as the mobile user density in China is and will continue to be much higher than that in other countries. More specifically, we propose a novel buffer sharing scheme to provide assured service for real-time layer-coded multimedia traffic, which can guarantee the specific packet loss requirement of each layer with UDP as the transport layer protocol. An adaptive optimal buffer configuration can be applied to achieve maximum resource utilization over the time-varying channel. Assured service is also provided to TCP data traffic for guaranteed throughput, where the cross-layer coupling between the TCP layer and link layer is exploited to efficiently utilize the wireless resources.

Proportional delay differentiation provision by bandwidth adaptation of class‐based queue scheduling

AbstractSupporting quality of service (QoS) over the Internet is a very important issue and many mechanisms have already been devised or are under way towards achieving this goal. One of the most important approaches is the so‐called Differentiated Services (DiffServ) architecture, which provides a scalable mechanism for QoS support in a TCP/IP network. The main concept underlying DiffServ is the aggregation of traffic flows at an ingress (or egress) point of a network and the marking of the IP packets of each traffic flow according to several classification criteria. Diffserv is classified under two taxonomies: the absolute and the relative. In absolute DiffServ architecture, an admission control scheme is utilized to provide QoS as absolute bounds of specific QoS parameters. The relative DiffServ model offers also QoS guarantees per class but in reference to the guarantees given to the other classes defined. In this paper, relative proportional delay differentiation is achieved based on class‐based queueing (CBQ) scheduler. Specifically, the service rates allocated to the classes of a CBQ scheduler are frequently adjusted in order to obtain relative delay spacing among them. The model presented can also be exploited in order to meet absolute delay constraints in conjunction with relative delay differentiation provision. Simulation experiments verify that our model can attain relative as well as absolute delay differentiation provided that the preconditions posed are satisfied. Copyright © 2004 John Wiley & Sons, Ltd.

Enhancing end-to-end QoS granularity in DiffServ networks via service vector and explicit endpoint admission control

The DiffServ model is considered as a scalable and viable solution to provide QoS in the Internet. However, the current DiffServ model can only provide a coarse end-to-end QoS granularity to individual data flows. This is undesirable for many network services such as the virtual private network (VPN), since it may result in low resource utilisation to guarantee the required QoS. In the paper the concept of service vector is proposed to provide finer QoS granularity in DiffServ networks through the framework of a distributed admission control scheme referred to as explicit endpoint admission control (EEAC). Specifically, by applying the proposed service vector and EEAC scheme, a data flow is allowed to choose different services at different nodes to achieve fine QoS granularity and architectural scalability. The models and solutions that represent the users' behaviour in selecting the appropriate network services are also discussed. The performance evaluation of the proposed approach demonstrates that the service vector and EEAC scheme can result in lower request drop ratio, satisfactory end-to-end performance, fine end-to-end QoS granularity, and lower cost for each user.