基于重叠网络的移动IPv6快速切换

基本的移动IPv6切换延迟太大，不能满足实时业务的要求。本文提出了一种基于重叠网络的移动IPv6快速切换算法，这种算法通过在两个不同的IPv6子网间设置重叠网络来实现IP层的无缝(零延迟)切换。文中给出了算法实现的网络结构及其切换过程，并且对其性能进行了分析。算法实现了移动IPv6快速切换，在大部分情况下都可以达到最佳性能。     

一种新的WLAN环境下移动IPv6的低时延切换方法

提出了一种IEEE 802.11无线局域网环境下移动IPv6的低时延切换方法NDPR.在不依靠链路层触发的条件下,NDPR使用非均匀检测模型来减小切换检测产生的时延,降低了切换检测过程的开销.通过IP地址与MAC地址的映射机制和转交地址的预注册机制,NDPR减小了移动IPv6的移动检测和转交地址配置过程的时延.仿真结果表明,该方法不但能够有效降低节点切换过程的时延,而且其性能优于以往相关的工作.     

一种新的基于移动IPv6的快速切换方案

基本的移动IPv6（MIPv6）切换延迟非常大,不能满足实时业务的要求。本文基于对MIPv6的切换时延的分析,提出了一种IEEE802．11无线局域网环境下MIPv6的低时延切换方法,该方法通过结合使用连接触发器和快速路由器公告,并通过IP地址与MAC地址的映射机制来优化切换过程。仿真结果表明,该方法能够有效降低节点切换过程的时延,同时其性能优于以往相关的工作。     

基于无线局域网的移动IPv6链路层切换

随着实时业务(如VOIP)的快速发展,移动IPv6技术的切换过程时延已经不能满足现代通信的需求,因此改进切换时延,提高切换质量很有必要.本文介绍了当一个移动节点(MN)尝试进行基于无线局域网的MIPv6链路层的切换时,利用邻居图算法或邻居缓存机制来减少扫描延迟,从而减少总切换延迟.     

层次化移动IPv6中基于TCP的快速切换性能分析

通过模拟环境，对快速切换式层次化移动IPv6机制中，基于TCP协议传输时的切换性能进行了分析，指出了’FCP的拥塞控制策略对切换性能产生的具体影响，为进一步提高切换性能提供了重要的参考。     

WLAN的移动IPv6快速切换研究

移 动 IPv6 标准切换包括移动 节点的二层切换、路由发 现、重复地址检测(DAD)、家 乡代理绑定更新(BU)、通信节 点绑定更新这几个环节,在此期 间移动节点不能收发应用的 IP 分 组。在无线链路质量不佳,或者 家乡代理与移动节点距离遥远等 情况下,标准切换过程引起的分 组传输延时和分组丢失无法满足 实时业务的要求。 移动 IPv6 的快速移动切换 研究是当前的一个热点,IETF 对 此提出了移动 IPv6 快速移动切换(FMIPv6)草案。FMIPv6 利用移 动节点或网络的二层链路信息, 对移动切换事件进行预测或快速 响应,通…     

基于2层、3层信息交互的移动IPv6切换延迟优化

移动IPv6作为下一代互联网的移动性管理的协议标准,能否很好的适应未来网络的需求,切换延迟是其中亟待解决的重要问题。移动IPv6的切换延迟主要由移动检测、地址自动配置和绑定更新三个阶段构成,本文通过分析移动IPv6的切换过程,设计并部署了一个模块,能够提取链路层的信息与移动IPv6进行交互,从而有效缩短移动IPv6切换过程中产生的延迟。     

基于NS-2的移动IPv6切换协议的仿真

对移动rpv6切换协议HMIPv6、FMIPv6、F-HMIPv6进行了详细介绍;引入网络仿真工具NS-2,利用其对3种移动IPv6协议的切换性能进行了比较和仿真,验证了F-HMIPv6具有良好的性能.     

基于特征投影的移动IPv6快速切换方法

研究了移动IPv6协议中的越区切换问题,提出了一种基于特征投影的移动IPv6快速切换方法。该方法通过构造先验切换经验与小区覆盖范围的映射关系来协助移动接入网关对切换目的地进行预测。仿真结果表明,文中方法能够获得比FPMIPv6更小的切换延迟,并具有较好的鲁棒性。     

基于冗余路由信息和预缓存策略的移动IPv6快速切换方法

研究了FMIPv6(MIPv6 fast handovers)协议中移动节点在预测出错情况下的IP连接恢复问题,提出了一种基于冗余路由信息和预缓存策略的快速切换方法RIRS(router information redundancy scheme).该方法通过构造冗余切换路由表来协助移动节点快速重构新的转交地址,并采用预缓存策略来保护切换过程中到达的数据分组.仿真结果表明,RIRS能够获得比FMIPv6更小的切换延迟及丢包率.     

一种移动IPv6的切换优化方案

移动节点在两个不同子网之间移动时产生切换。移动节点的切换技术是保证实时业务服务质量的关键问题之一。目前比较经典的三种切换机制是快速移动IPv6、层次型移动IPv6和快速层次移动IPv6。在简单介绍了三种机制原理并分析了它们的不足后,提出了一种自适应移动IPv6切换时延优化方案。     

移动IPv6技术

本文简要介绍了移动IPv6的基本概念和工作机制，在此基础上详细地介绍了移动IPv6中的关键技术。最后介绍了移动IPv6的一些应用。     

移动IPv6概述

文章分析了IPV6支持移动性的优势，概述了移动IPv6协议，并对一些热点问题，如快速切换、平滑切换、移动管理、AAA和服务质量等进行了探讨。     

Performance Enhancement of Fast Handover for MIPv6 by Reducing Out-of-Sequence Packets

FMIPv6 can reduce packet loss using a tunnel-based handover mechanism which relies on L2 triggers, such as transmitting a packet from a previous access router (PAR) to a new access router (NAR). However, this mechanism may result in decreasing the performance of TCP due to out-of-sequence packets arriving between the tunneled packets from the Home Agent and PAR, and the directly transmitted packets from the correspondent node (CN). In this paper, we propose a new scheme called EF-MIPv6 that uses a modified snoop protocol to prevent the packet reordering problem. This new scheme can prevent sequence reordering of data packets and improve the performance of TCP using enhanced fast binding update (EF-BU). This approach requires modification of the TCP header to execute the last packet expression from the PAR, include a new polling data packet, and use the modified access point system. Simulation results demonstrate that managing the packet sequence in our proposed scheme greatly increases the overall TCP performance in a Mobile IPv6 and FMIPv6 networks.

WLAN中语音业务质量保证

本文阐述了在WLAN(无线局域网)中开展语音业务所存在的问题,针对这些问题,从编码、切换和调度几个方面提出了改善无线局域网中语音业务质量的方法.     

WLAN场景的IPv6宽带接入认证技术

介绍了WLAN接入现有技术,根据现有技术分析了WLAN宽带接入技术在IPv6演进过程中面临的挑战,并根据IPv6本身的特点提出了现有技术改造和演进方案,同时也对IPv6宽带部署阶段,如何更好地进行WLAN接入控制做出了研究和分析。     

A Low Latency Handoff Algorithm for Voice over IP Traffics in the Next Generation Packet-Based Cellular Networks: Cellular Mobile IPv6

In the mobile communication environments, Mobile IP is defined to provide users roaming everywhere and transmit information freely. It integrates communication and network systems into Internet. The Mobile IPv6 concepts are similar to Mobile IP, and some new functions of IPv6 bring new features and schemes for mobility support. Two major problems in mobile environments are packet loss and handoff. To solve those problems, a mobile management scheme – the cellular mobile IPv6 (CMIv6) is proposed. Our approach isbased on the Internet Protocol version 6 and is compatible with the Mobile IPv6 standard. Besides, it also combines with the cellular technologies which is an inevitable architecture for the future Personal Communication Service system (PCS). In this paper, {Cellular Mobile IPv6 (CMIv6)}, a new solutionmigrated from Mobile IPv6, is proposed for mobile nodes moving among small wireless cells at high speed. This is important for future mobile communication trends. CMIv6 can solve the problems of communication break off within smaller cellular coverage during high-speed movement when packet-switched data or the real-time voice messages are transmitted. Voice over IP (VoIP) packets were chosen to verify this system. The G.723.1 Codec scheme was selected because it has better jitter resistance than GSM and G729 in a packet-based cellular network. Simulation results using OPNET show smooth and non-breaking handoffs during high-speed movement.     

BSS transition optimizations and analysis for VoIP over WLAN

Voice over IP (VoIP) is emerging as a critical application for IEEE 802.11 Wireless Local Area Networks (WLANs). However, the limited range of the IEEE 802.11 radio forces frequent transitions from one access point to another. Moreover, the introduction of IEEE 802.11i security and IEEE 802.11e Quality of Service (QoS) has increased the average transition time from ms to seconds, leaving mobile users with the unenviable dilemma of choosing good security and QoS while sacrificing real-time performance, or gaining acceptable real-time performance at the expense of security and QoS. Thus, optimizations to device transitioning that will provide an acceptable balance of latency, security, and QoS are needed to enable VoIP. This paper analyzes WLANs MAC layer transition procedure and optimizations being considered by IEEE 802.11 Working Group to improve transition times while retaining good security and QoS. The transition time improvements proposed in this paper are achieved through discovery phase optimizations and transition phase optimizations. The selective scanning and smart AP selection algorithms are designed to optimize the discovery phase to enable the mobile device to better exploit its ambient radio resource environment. The transition phase optimization seeks to accelerate device transition without compromising security. The paper then identifies security flaws in the current design and proposes simple corrections. Finally, experiment results for transition optimization are explained that demonstrate a significant increase in transition efficiency.     

任播服务在VoIP系统中应用的研究

VoIP是在Internet上传输语音的技术,这种技术带来新的通信方式。任播服务是一种新的网络应用,将任播服务应用到VoIP中可以有效提高VoIP的服务质量。