Mobile flow-aware networks for mobility and QoS support in the IP-based wireless networks

As the volume of mobile traffic consisting of video, voice, and data is rapidly expanding, a challenge remains with the mobile transport network, which must deliver data traffic to mobile devices without degrading the service quality. Since every Internet service holds its own service quality requirements, the flow-aware traffic management in fine granularity has been widely investigated to guarantee Quality of Service (QoS) in the IP networks. However, the mobile flow-aware management has not been sufficiently developed yet because of the inherent constraints of flow routing in the mobile networks regarding flow-aware mobility and QoS support. In this paper, we propose a flow-aware mobility and QoS support scheme called mobile flow-aware network (MFAN) for IP-based wireless mobile networks. The proposed scheme consists of dynamic handoff mechanisms based on QoS requirements per flow to reduce the processing overhead of the flow router while ensuring QoS guarantee to mobile flows. The performance analyses of the proposed scheme demonstrate that MFAN successfully supports the mobile flow traffic delivery while satisfying the QoS requirement of flows in the wireless mobile IP networks.     

Fair Delay Optimization-based Resource Allocation Algorithm for Video Traffic over Wireless Multimedia System

The major issue related to the realization of wireless multimedia system is the design of suitable medium access control (MAC) protocol. The design challenge is to maximize the utilization of the limited wireless resources while guaranteeing the various quality of service requirements for all traffic classes especially for the stringent real-time constraint of real time variable bit rate (rt-VBR) video service. In this paper a novel resource allocation algorithm for video traffic is proposed. The proposed allocation algorithm aims to provide fair delay for video packets by minimizing the delay difference among transmitted video packets. At the same time it adaptively controls the allocated resources (bandwidth) for video traffic around the corresponding average bit rate, and has the ability of controlling the quality of service (QoS) offered for video traffic in terms of packet loss probability and average delay. A minimized control overhead of only two bits is needed to increase the utilization efficiency. Simulation results show that the proposed algorithm achieves very high utilization and provides nearly fair delay among video packets. Its efficiency is also investigated under traffic integration condition with voice and data traffic to show that the QoS offered to video traffic does not change in the presence of the highest priority voice traffic while data traffic increases the channel utilization to 98% by using the remaining bandwidth after voice and video traffic while a good QoS is offered to voice and data traffic.

QoS support for integrated services over CATV

Cable TV has emerged as a promising access network infrastructure for the delivery of voice, video, and high-speed data traffic. A central issue in the design of protocols for CATV networks is to support different levels of QoS for diverse user applications. While CATV service providers and equipment have standardized, in the so-called MCNS protocol, the basic network architecture and interfaces, issues in the MAC layer for QoS support are likely to be left for differentiation in vendor products. This article first presents an overview of the basic CATV network architectural assumptions and the set of QoS requirements for supporting integrated services over CATV. It then discusses a MAC layer scheduling protocol that can efficiently multiplex constant bit rate traffic, such as voice over IP with guaranteed delay bound, and best-effort traffic, such as data services with minimum bit rate guarantee, while achieving fairness on any excess available bandwidth. The performance of this algorithm is illustrated by simulation results using Opnet. We also discuss a dynamic polling mechanism that enhances the link utilization while preserving delay bounds for latency-critical traffic     

MPLS在移动IP网络中的应用

移动通信网络和IP网络的融合推动了电信产业的发展。在一个统一的IP网络平台上传输话音、数据、视频、图像将是大势所趋。目前针对移动用户的服务质量(QoS)要求,也正面临着很大的挑战。在移动IP网络中,由于用户的频繁移动使得端到端的QoS保证和移动切换(handoff)管理更加复杂。多协议标签交换(MPLS)技术作为借鉴了面向连接网络的优越性和实现流量工程的重要技术,为网络提供了较好的QoS保证。文章介绍了MPLS技术是如何应用在移动IP网络中,解决了诸如认证、QoS、流量工程等问题。     

无线网络中的QoS和策略管理测试(续一)

上一期中,我们论述了策略管理和QoS在无线网络中的作用,并介绍了3GPP所定义的实现方式。在本期中,我们将继续讨论QoS和策略管理的测试方法,并介绍IXIA在一个北美运营商实验室里实现VoLTE测试的成功案例。6无线网络的服务质量验证全球运营商正花费数十亿美元购买设备和频谱来升级他们的移动宽带网络。通过网络升级,运营商旨在     

QoS provisioning for multimedia wireless networks

As we move towards IP-based multimedia wireless networks with voice, video and data convergence, quality of service (QoS) provisioning will become an increasingly challenging task. One implication is that greater emphasis on managing the call admission and overall network resources will be needed. This paper presents a conservative and adaptive quality of service (CAQoS) framework for provisioning the QoS for both real-time and non-real-time traffic in a multimedia wireless network. Unlike most conventional schemes, which gradually scale down the bandwidth of ongoing connections to accommodate new connection/hand-off requests, CAQoS introduces an early scaling-down of bandwidth for new connections based on a designated provisioning model. The performance of a CAQoS system is evaluated through simulations of a realistic wireless environment. Simulation results show that CAQoS meets our design goals and outperforms conventional schemes.     

CAC-OLSR: Extending OLSR to Provide Admission Control in Wireless Mesh Networks

This work presents an admission control mechanism for multi-hop wireless mesh networks based on the IEEE 802.11 standard and the OLSR routing protocol. This mechanism, called CAC-OLSR, aims at ensuring that traffic flows with quality of service (QoS) requirements, especially voice and video, are only admitted in the mesh network if it has available resources in order to provide flow requirements. In addition, QoS requirements of previously admitted traffic flows cannot be violated. The proposal was evaluated with NS-2 and Evalvid simulations.     

Per-Stream QoS and Admission Control in Ethernet Passive Optical Networks (EPONs)

Ethernet passive optical networks (EPONs) are designed to deliver services for numerous applications such as voice over Internet protocol, standard and high-definition video, video conferencing (interactive video), and data traffic. Various dynamic bandwidth allocation and intra-optical network unit (ONU) scheduling algorithms have been proposed to enable EPONs to deliver differentiated services for traffic with different quality of service (QoS) requirements. However, none of these protocols and schedulers can guarantee bandwidth for each class of service nor can they protect the QoS level required by admitted real-time traffic streams. In this paper, we propose the first framework for per-stream QoS protection in EPONs using a two-stage admission control (AC) system. The first stage enables the ONU to perform flow admission locally according to the bandwidth availability, and the second stage allows for global AC at the optical line terminal. Appropriate bandwidth allocation algorithms are presented as well. An event-driven simulation model is implemented to study the effectiveness of the proposed schemes in providing and protecting QoS.     

Smoothing and transporting video in QoS IP networks

Real‐time traffic such as voice and video, when transported over the Internet, demand stringent quality of service (QoS) requirements. The current Internet as of today is still used as a best effort environment with no quality guarantees. An IP‐based Internet that supports different QoS requirements for different applications has been evolving for the past few years. Video streams are bursty in nature due to the instant variability of the video content being encoded. To help mitigate the transport of bursty video streams with minimal loss of information, rate‐adaptive shapers (RASs) are usually being used to reduce the burstiness and therefore help preserve the desired quality. When transporting video over a QoS IP network, each stream is classified under a specific traffic profile to which it must conform, to avoid packet loss and picture quality degradation. In this paper we study, evaluate and propose RASs for the transport of video over a QoS IP network. We utilize the encoding video parameters for choosing the appropriate configuration needed to support the real‐time transport of Variable Bit Rate (VBR) encoded video streams. The performance evaluation of the different RASs is based on the transport of MPEG‐4 video streams encoded as VBR. The performance is studied based on looking at the effect of various parameters associated with the RASs on the effectiveness of smoothing out the burstiness of video and minimizing the probability of packet loss. Copyright © 2005 John Wiley & Sons, Ltd.     

A simplified performance evaluation for bursty multiclass trafficin ATM systems

In broadband ISDN with ATM, various kinds of traffic, such as voice, data and video, share the common transmission resource. For such multiclass traffic systems, it is necessary to evaluate the grade of service (GOS) for individual traffic. In particular, for the ATM networks integrating voice and video which are of bursty property and delay sensitive, the individual performance evaluation for the mixed bursty traffic an important problem. The authors propose a simplified evaluation of the individual mean waiting time for the bursty multiclass systems appearing in the ATM network and show numerical examples for voice/video system     

基于区分服务的IP-UMTS视频传输QoS机制

为了满足在以IP作为骨干网协议,以通用移动通信系统(UMTS)作为接入网的异构网络环境中视频传输的服务质量要求.提出了基于区分服务的视频传输服务质量机制,给出了区分服务业务等级到视频数据帧和区分服务业务等级到UMTS业务类别的映射关系.使用仿真的实验环境对给定的服务质量机制进行了测试,实验结果表明该服务质量机制能有效地提高IP-UMTS异构网络中视频传输的服务质量.     

Internet services beyond best effort

The packet-based data transmission of the Internet allows the multiplexing of a variety of simultaneous connections originating from sources with different characteristics (e.g. voice, video, data). Traditional Internet is based on a best effort service, whereas future Internet services make more and more special demands on the communication network. This paper presents a general overview of fundamental mechanisms for guaranteeing Quality of Service (QoS) in the current and future Internet. After introducing general QoS concepts, basic mechanisms in network routers are investigated. Furthermore, the two basic architectures of Integrated Services (IntServ) and Differentiated Services (DiffServ) are discussed in detail. Finally, the analytical investigation of a special Voice-over-IP scenario demonstrates the applicability of the relevant QoS concepts and their positive consequences with respect to the quality of this voice service. A short overview of current hot research topics concludes the paper.     

IPhone系统中的QoS控制系统的设计与实现

本文提出一种用于解决IPhone系统语音质量问题的端到端的服务质量控制方案.该QoS控制系统依据端到端的准入控制结果,为时间敏感的语音数据流建立/维护流状态并保留网络资源,在数据传输阶段使用虚拟时间片公平轮转算法保证流的统计特性.本文首先描述了QoS控制系统的组成结构,然后给出网络资源分配的准入控制算法和流量控制算法,最后依据实验数据讨论该系统对语音质量的控制效果.     

Performance evaluation of the RQMA-CDMA scheme for multimedia traffic with QoS guarantees

The rapid growth of cellular mobile technology in recent years, coupled with the explosive growth of the Internet, has significantly increased the demand for wireless data services. Traffic on mobile devices is expected to be a mix of real-time traffic such as video, voice, and data, with users requiring diverse quality of service (QoS) guarantees for different types of traffic (video, voice and data). One of the primary challenges of providing QoS is how to prioritize and allocate network resources among contending applications. In order to achieve these goals, a scheduling scheme that can provide equitable and effective packet routing is required. This paper proposes a scheduling scheme called remote queuing multiple access-code division multiple access (RQMA-CDMA), whose purpose is to equitably assign bandwidth resources with QoS guarantees to different mobile devices. RQMA-CDMA is a rate scheduling scheme that can be used to assign bandwidth resources in conjunction with GPS (generalized processor sharing). Additionally, we analyze an admission control that is based on signal to interference plus noise ratio (SINR) for multimedia traffic. Finally, the performance of RQMA-CDMA is evaluated and compared to schemes based on CDMA-GPS according to dropped packets, delay, and throughput.     

Quality‐of‐service‐aware cluster‐based service discovery approach for mobile ad hoc networks

This paper presents a quality‐of‐service (QoS) distributed service discovery approach for mobile ad hoc network environments. The approach builds upon a clustered topology, where the clusterhead (CH) is assigned additional roles having to do with maintaining a directory of services in the network and aggregating and computing QoS scores about service providers (SPs) from requesting nodes (RNs) and the providers themselves. To reduce the amount of overhead traffic, the design makes extensive use of piggybacking for relaying and updating the CHs with QoS scores. A mobile device that is interested in a certain service submits a request to its CH, which uses cached QoS data to return a ranked list of SPs that offer the type of requested service. On the basis of its interaction with the SP, the device sends the CH next time it makes a request a score reflecting its perception of the SP's QoS. Over time, the CH develops robust QoS data that it uses to help devices obtain the best available service. Theoretical analysis and experimental evaluation based on simulations prove the advantages of the proposed system and the effectiveness of its operations. Copyright © 2013 John Wiley & Sons, Ltd.     

A packet reservation multiple access (PRMA)-based algorithm for multimedia wireless system

The major issue in the wireless multimedia system design is the selection of a suitable channel sharing media access control (MAC) protocol. The design challenge is to identify a wireless "multimedia capable" MAC protocol that provides a sufficient degree of transparency for many different kinds of services. This protocol should guarantee different quality of service (QoS) parameters for different types of traffic while in the same time achieving high throughput. In this paper a MAC protocol to serve different kinds of traffic, namely voice, data, and, real time variable bit rate (rt-VBR) video is proposed. The transmission time scale is divided into frames. Each frame is subdivided into N time slots. In this protocol, a fixed number of slots M out of 150 time slots are reserved at the beginning of every frame to transmit some of the video packets arriving during the frame interval. The rest of the video packets contend with the voice and data packets for the remaining time slots of this frame as in normal packet reservation multiple access (PRMA). One objective of this paper is to find the optimum value of M allowing the maximum number of voice and data users to share the RF channel with one video user. Another objective is to find the optimum permission probabilities of sending contending voice, data, and video packets allowing the maximum number of users sharing the RF channel. The dropping probability requirement for video is examined.     

辽宁联通城域网QoS研究及部署

为保证IP城域网多业务承载服务质量,根据语音、视频和数据等不同业务的特性,实现QoS差异化保障,出现网络拥塞等异常情况时,可以将网络资源优先配置给高价值业务。辽宁联通从城域网网络架构、业务开展情况、等级设计、业务带宽分配以及不同设备对QoS的支持能力等方面展开了深入的分析研究,并在全省城域网部署了基于DiffServ的IP QoS技术应用。     

Application of cost models over traffic dimensioning with QoS restrictions

Network operators and Internet service providers are offering “Triple Play” products integrating services with different quality of service (QoS) requirements. The provision of QoS guarantees implies the revision of current dimensioning methods and consequences for costing and pricing. This paper proposes a cost model which considers QoS parameters, based on the Total Element Long Run Incremental Cost (TELRIC) model, calculating the cost of a network element and distributing it over the different services whose traffic uses it, taking into account the QoS requirements of each service. For this purpose, three traffic engineering methods are analyzed: complete traffic aggregation by “Over-engineering,” complete traffic segregation by separated virtual tunnels, and partial traffic aggregation by priority queuing. As an example, the cost model is applied to the connection in a Next Generation Network aggregation network for estimating the influence of QoS and traffic engineering on the cost estimation under the TELRIC model.     

Managing QoS requirements for video streaming: from intra‐node to inter‐node

Streaming video over IP networks has become increasingly popular; however, compared to traditional data traffic, video streaming places different demands on quality of service (QoS) in a network, particularly in terms of delay, delay variation, and data loss. In response to the QoS demands of video applications, network techniques have been proposed to provide QoS within a network. Unfortunately, while efficient from a network perspective, most existing solutions have not provided end‐to‐end QoS that is satisfactory to users. In this paper, packet scheduling and end‐to‐end QoS distribution schemes are proposed to address this issue. The design and implementation of the two schemes are based on the active networking paradigm. In active networks, routers can perform user‐driven computation when forwarding packets, rather than just simple storing and forwarding packets, as in traditional networks. Both schemes thus take advantage of the capability of active networks enabling routers to adapt to the content of transmitted data and the QoS requirements of video users. In other words, packet scheduling at routers considers the correlation between video characteristics, available local resources and the resulting visual quality. The proposed QoS distribution scheme performs inter‐node adaptation, dynamically adjusting local loss constraints in response to network conditions in order to satisfy the end‐to‐end loss requirements. An active network‐based simulation shows that using QoS distribution and packet scheduling together increases the probability of meeting end‐to‐end QoS requirements of networked video. Copyright © 2005 John Wiley & Sons, Ltd.     

Dynamic Code Assignment Medium Access (DCAMA) Protocol for Wireless Integrated Services Networks

A medium access control (MAC) protocol for wireless mobile networks that supports integrated services and provides quality of service (QoS) support is presented and evaluated via simulation. A controlled random access protocol which allows all terminals to dynamically share a group of spread spectrum spreading codes is used. The protocol provides mobile terminals the access control required for efficient transfer of integrated traffic with QoS guarantees. Two service classes are provided; "best-effort" service, with priority queueing, and reserved bandwidth circuit service. The performance of the protocol is evaluated via simulation for traffic consisting of integrated voice, data and compressed video. The performance assessment measure is packet delay.