VOIP业务以及相关QoS性能的网络优化研究

简要介绍了VOIP传输的基本原理、传输机制,以及对影响VOIP业务QoS性能的3个主要因素 (时延、抖动和丢包率)进行分析,提出了利用MPLS、diffserv-aware TE(流量工程)集成模型进行端到端QoS 性能优化的方法和解决办法。MPLS、diffserv-aware TE能够感知CoS(服务等级),并提供根据CoS细粒度来预留带宽资源,在每个CoS级别提供MPLS容错的机制,能够为VOIP提供低丢失、低延迟、低抖动以及确定的带宽服务,很好地满足服务质量的要求．     

VOIP业务以及相关QoS性能的网络优化研究

简要介绍了VOIP传输的基本原理、传输机制，以及对影响VOIP业务QoS性能的3个主要因素（时延、抖动和丢包率）进行分析，提出了利用MPLS、diffserv—aware TE（流量工程）集成模型进行端到端QoS性能优化的方法和解决办法。MPLS、diffserv—aware TE能够感知CoS（服务等级），并提供根据CoS细粒度来预留带宽资源，在每个CoS级别提供MPLS容错的仉制，能够为VOIP提供低丢失、低延迟、低抖动以及确定的带宽服务，很好地满足服务质量的要求。     

实时业务端到端QoS测评

业务对网络性能的要求直接来源于业务对端到端客户感知(主观质量)的满意程度的需求.尤其对于目前在网络中涌现出的越来越多的实时业务,如VoIP、IPTV、 VOD 等业务对端到端的可用带宽、时延、抖动和丢包十分敏感,这些性能参数严重影响着此类业务的开展和运营维护.这些指标的组合整体反映了承载网络所能提供的QoS,因此准确把握这些网络QoS指标是对网络承载性能进行测评的基础.     

IP电话接入端QoS服务的设计与实现

IP电话系统的业务是实时业务，对延迟、抖动等因素十分敏感，而IP网络本身并不提供QoS服务，所以QoS服务实现是IP电话系统必须研究的内容。本文在新一代电话体系结构的基础上设计了一个带控器来控制H.323zone的出口带宽资源，以提供端QoS服务。从而带控器与主干QoS服务一起构成IP电话系统的端到端QoS服务系统。     

基于H.323的VoIP系统QoS实现研究

文章提出了一种QoS增强的VoIP体系结构，增加了连接准入控制功能，提供了语音分组的IP优先服务，并改进了抖动缓冲的设计，使VoIP系统的QoS得到很大改善。     

IP网络的服务质量讲座第2讲 IP网络性能参数与指标

1IP QoS与CoS 与IPQoS（服务质量）相对应的一个概念是业务类型（CoS）的概念，因此这里首先介绍CoS。虽然目前业界对二者的区别还没有一个标准的界定，但一般认为，CoS对业务进行简单的分类，为流提供有优先级差别的服务，因此并不一定能够保证服务质量。另外，从实现的角度看，CoS具有以下两个特征：·CoS技术一般只规定为数不多的几种（如8种）服务类型。当某个流提出服务请求后，CoS技术把该流的需求请求聚合到CoS所定义的某种服务类型。因此CoS技术所提供的服务的粒度一般比较粗，不够精确。·IP网络中的路由器或交…     

建设电信级的广电NGB全业务接入网（下）

服务质量（QoS）保障1.端到端QoS保障多业务IP承载网必须能够区别业务所需的QoS,传统的IP网络采用的过载设计容易发生拥塞导致丢包。由于视频（组播）和VoIP等业务无法很好处理丢包,因此要求对视频和语音数据流必须能够区分优先级,以确保拥塞情况下的优先调度。     

基于SIP协议的VoIP系统的QoS机制的研究

IP电话是一种数字电话,是技术创新的一种通信服务业务,它把语音、压缩编码、打包分组、分配路由、存储交换、解包解压等各种交换处理组合在IP网或互联网上实现语音通信。因特网语音通信是VoIP技术的一个最典型的,也是最有前景的应用领域。介绍了VoIP的通信原理、关键技术和系统通信中的SIP协议,分析了影响VoIP的QoS的主要原因,阐述了时延、抖动、丢包和回声等影响QoS的机理和解决方案。     

一种基于分层架构的端到端QoS保障系统与方法

随着互联网+、NFV/SDN、5G/MEC、业务编排器的快速发展,业界对端到端质量保障需求旺盛,通过研究一种基于分层架构的端到端QoS保障系统与方法,采用新的QoS质量保障系统,通过省级业务编排器,与全国业务编排器、省分/地(市)核心云、地(市)边缘云、省内核心网、城域网、传输网、宽带网对接为全网提供端到端的全业务QoS保障,并进行云网协同的QoS保障,提升业务体验,为各类应用所服务的用户提供动态带宽加速、QoS保障等服务。     

在MPLS网络中如何保证VoIP的QoS

在以IP为基础的网络中,IP网络上传送语音(VoIP)成为新一代语音系统的代表,但其业务质量因由IP网络承载而受到限制.多协议标签交换(MPLS)是当前被普遍看好的高速骨干网络技术,通过MPLS,第三层的路由可以得到第二层技术的很好补充,以保证端到端的服务质量(QoS).将MPLS的QoS特性与区分服务(DiffServ)相结合,可实现更优化的网络业务QoS.     

IP QoS解决方案

IPQoS技术的发展经历了从无QoS保障的“尽力而为”的网络服务,基于资源预留协议的IntServ解决方案,基于差分服务代码点(DSCP)的DiffServ解决方案,MPLSTE技术,到MPLSDiffServ-AwareTE解决方案的历程。其中,IPDiffServ,MPLSDiffServE-LSP以及MPLSDiffServ-AwareTE将成为主流的QoS技术。本文还介绍了华为公司IPQoS解决方案的组网应用:VoIP的QoS解决方案、多网合一的QoS解决方案和城域网多媒体业务的QoS解决方案。     

MPLS VPN不同解决方案的比较分析

MPLS VPN是一种基于多协议标记交换(MPLS)技术的IP虚拟专用网络(VPN),是通过在网络路由和交换设备上应用MPLS技术,简化核心路由器的路由选择方式,并结合传统路由技术的标记交换来实现的.本文介绍了MPLS VPN的基本原理和发展现状,分析和比较了主要的2层(L2)和3层(L3)MPLS VPN技术.     

VoIP Performance over HSPA with Different VoIP Clients

High Speed Packet Access (HSPA) Holma H, Toskala A (in HSDPA/HSUPA for UMTS, 2006) is expected to provide enough bandwidth for voice over IP (VoIP) service. In this article we assess the performance of VoIP over HSPA with different VoIP clients and voice codecs. The simulations results show that VoIP can have a good voice quality over HSPA if a proper VoIP client and codec is used. However it is possible that the delay can increase with early HSPA implementations (mobile, network).     

Traffic Measurement for Traffic Engineering in IP/MPLS Based Telecom Core Networks

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Seven myths about voice over IP

Voice over Internet Protocol (VoIP) is one of the fastest growing and most misunderstood technologies in the world at the moment. Confusion, outdated beliefs and urban mythology reign over such simple issues as how it works, the quality of the calls, and, of course, how much it costs. This paper examines seven existing myths about VoIP. These myths are that: (1) VoIP is free; (2) the only difference between VoIP and regular telephony is the price; (3) the quality of service isn't an issue nowadays because there's plenty of bandwidth in the network; (4) VoIP can't replace regular telephony because it still cannot guarantee quality of service; (5) VoIP is just another data application; (6) VoIP isn't secure; and (7) a phone is a phone is a phone.     

Voice over the internet: A tutorial discussing problems and solutions associated with alternative transport

This article provides a tutorial overview of voice over the Internet, examining the effects of moving voice traffic over the packet switched Internet and comparing this with the effects of moving voice over the more traditional circuit-switched telephone system. The emphasis of this document is on areas of concern to a backbone service provider implementing Voice over IP (VoIP). We begin by providing overviews of the Plain Old Telephone Service (POTS) and VoIP. We then discuss techniques service providers can use to help preserve service quality on their VoIP networks. Next, we briefly discuss Voice over ATM (VoATM) as an alternative to VoIP. Finally, we offer some conclusions.     

Enabling novel premium service classes in DiffServ over MPLS‐enabled network

Network resources dimensioning and traffic engineering influence the quality in provisioned services required by the Expedited Forwarding (EF) traffic in production networks established through DiffServ over MPLS‐enabled network. By modeling EF traffic flows and the excess of network resources reserved for it, we derive the range of delay values which are required to support these flows at DiffServ nodes. This enables us to develop an end‐to‐end (e2e) delay budget‐partitioning mechanism and traffic‐engineering techniques within a framework for supporting new premium QoS levels, which are differentiated based on e2e delay, jitter and loss. This framework enables ingress routers to control EF traffic flow admission and select appropriate routing paths, with the goal of EF traffic balancing, avoiding traffic congestion and getting the most use out of the available network resources through traffic engineering. As a result, this framework should enable Internet service providers to provide three performance levels of EF service class to their customers provided that their network is DiffServ MPLS TE aware. Copyright © 2008 John Wiley & Sons, Ltd.     

Performance Optimizations for Deploying VoIP Services in Mesh Networks

In the recent past, there has been a tremendous increase in the popularity of VoIP services as a result of huge growth in broadband access. The same voice-over-Internet protocol (VoIP) service poses new challenges when deployed over a wireless mesh network, while enabling users to make voice calls using WiFi phones. Packet losses and delay due to interference in a multiple-hop mesh network with limited capacity can significantly degrade the end-to-end VoIP call quality. In this work, we discuss the basic requirements for efficient deployment of VoIP services over a mesh network. We present and evaluate practical optimizing techniques that can enhance the network capacity, maintain the VoIP quality and handle user mobility efficiently. Extensive experiments conducted on a real testbed and ns-2 provide insights into the performance issues and demonstrate the level of improvement that can be obtained by the proposed techniques. Specifically, we find that packet aggregation along with header compression can increase the number of supported VoIP calls in a multihop network by 2-3 times. The proposed fast path switching is highly effective in maintaining the VoIP quality. Our fast handoff scheme achieves almost negligible disruption during calls to roaming clients     

Service differentiation in IP/MPLS over ASON/GMPLS networks

There is a general agreement that the future infrastructure for broadband communications will consist of Automatically Switched Optical Networks (ASONs) controlled by the Generalized Multi-Protocol Label Switching (GMPLS) control plane. Due to the convergence of most services on the Internet Protocol (IP) layer, ASON/GMPLS networks need to provide transport for a variety of applications having different Quality of Service (QoS) requirements. This implies that the Differentiated Service paradigm, which improves the QoS in pure IP networks, needs to be extended to the new underlying infrastructure. This article proposes and compares three schemes for the service differentiation in IP/MPLS over ASON/GMPLS networks. Simulation results demonstrate that a fair trade-off between QoS and resource utilization is achieved when combining routing policy differentiation (RPD), virtual topology differentiation (VTD), and virtual topology sharing (VTS) techniques. The RPD technique decides on the multilayer routing policy to apply depending on the Class of Service (CoS). The VTD technique transports different CoS over different independent virtual topologies. The VTS technique introduces a certain degree of resource sharing among the different virtual topologies.     

MPLS VPN在大客户组网业务中的应用

根据当前网络发展趋势和大客户组网的业务需求,首先,分析MPLS VPN技术较传统ATM/SDH组网的优势;其次,介绍运营商应用MPLS VPN技术承载大客户组网业务,同时结合QoS、链路保护技术提高业务质量和可靠性的各种具体方案。主要方案有单一MPLS VPN和多种MPLS VPN技术组合应用两类。单一MPLS VPN又分为三层MPLS VPN(BGP/MPLS VPN)和二层MPLS VPN(VLL,VPLS);多种MPLS VPN技术组合应用又可分为BGP/MPLS VPN终结VLL,VPLS终结VLL和VLL与VLL对接。通过实验室的测试,验证了以上方案的可行性和承载效果,给出了采用不同的MPLS VPN方式承载大客户组网业务的应用场景。