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.     

快速层次移动IPv6的乒乓切换研究

针对现有的预测式FMIPv6(快速移动IPv6)没有提供域内乒乓切换机制,因而可能导致大量远程注册开销和系统通信开销的问题,在FMIPv6的基础上引入HMIPv6(分层移动IPv6)层次结构,提出了一种基于FHMIPv6(快速层次移动IPv6)的乒乓切换优化方案。分析结果表明,与FHMIPv6相比,所提方案在乒乓切换模式下能够有效减少时延和丢包率,进一步提高吞吐量。     

一种优化的分层式移动IPv6路由策略的分析与研究

通过分析分层移动IPv6协议，提出一种基于分层机制的优化移动IPv6路由管理策略。该策略支持路由优化，能在域内、域间移动时实现快速切换以减少时延，提高网络资源利用率。     

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。     

基于流的移动IPv6快速切换方法

文章介绍了一种基于流的移动IPv6快速切换方法．即路由器利用IPv6的业务流的信息把各个业务流重定向到移动节点的新转交地址上．这种重定向的方式是在MN绑定更新注册的过程中进行的．使得移动节点在向家乡代理的注册还未完成之前．便能与通信对端进行正常通信，这样大大减少了切换时延．提高了切换效率．另外．本文通过理论分析．将此方法与常规的移动IPv6和分层移动IPv6机制进行了比较．并利用NS-2网络模拟器的仿真数椐对在此方法下不同类型的业务流的传输进行了分析，验证其具有较为良好的性能。     

移动IPv6切换技术的研究

切换技术是移动IPv6技术的关键技术之一,其优劣在很大程度上决定了MN在移动通信过程中的通信质量。本文介绍了移动IPv6的工作原理,阐述了移动IPv6切换的关键技术,以及三种切换的实现方式。     

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.     

一种基于层次移动IPv6网络的动态HA机制

在移动IPv6中,当MN(移动节点)位于外地网络时,发向MN的数据报文需要首先路由至HA(家乡代理),然后再转发至MN的当前位置.为了解决上述方式路由效率较低的问题,提出了一种在层次移动IPv6环境中的动态HA机制,并且给出了基于这种机制的全IP无线网络结构.在本方案中,通过利用MIPv6的本身特性,并结合一种安全的动态DNs(域名服务)更新机制,实现MN家乡地址和HA的动态配置,有利于简化网络管理,提高路由效率以及实现HA负载均衡等.另外,通过AAA(认证、授权和计费)上下文预转移机制,可以有效减小域间切换时延.     

层次移动IPv6的增强切换方案

随着互联网技术与移动通信技术飞速发展,移动IPv6技术已经成为下一代移动互联网的研究热点。切换技术是影响移动互联网实时运行质量的重要技术之一。低延迟、低丢包的无缝切换方案对移动IPv6的性能至关重要。层次移动IPv6(HMIPv6)利用移动锚点(MAP)降低了延迟和数据丢失。然而,只有移动节点在同一MAP域的网络上进行切换时,HMIPv6才能有效减少延迟。当移动节点在不同MAP域的网络移动时,其切换性能并不优于标准移动IPv6。文章针对层次移动IPv6提出了一种增强切换方案(EHMIPv6),该方案在HMIPv6的基础上实现并行重复地址检测(PDAD),以减少不同区域网络间切换的延迟。分析表明,该方案比HMIPv6具有更好的性能。     

移动IPv6路由优化性能分析

用NS-2.1b6＋Mobiwan进行仿真实验,给出了移动IPv6三角路由和优化路由之间的性能比较分析。在仿真实验中,检测了移动节点在广域IPv6网移动时通信对端节点和移动节点之间的端到端分组时延。实验结果表明,移动IPv6优化路由的性能明显优于三角路由。     

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。     

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。     

A Scheme for Supporting Fast Handover in Hierarchical Mobile IPv6 Networks

This Letter proposes a scheme that supports a fast handover effectively in hierarchical mobile IPv6 networks (F‐HMIPv6) by optimizing the associated data and control flows during the handover. By NS‐2 simulation, we show that the proposed scheme can give better handover performance than a simple combination of existing schemes.     

一种减少移动IPv6切换延时的新方法

切换问题是移动计算环境中最基本的问题。理想的切换是指同时具备快速切换和平滑切换能力的无缝切换;快速切换就是要求系统具有最小的切换时延,平滑切换则要求系统具备最低的丢包率。现提出一种基于组播的平滑切换框架模型,该模型的基本思想是让移动节点本身携带途经的接入路由器绑定更新队列,每当移动节点到达一个新的链路并获得该链路的转交地址,就向家乡代理和队列成员进行组播。该模型有效地减少了数据包的丢失率,减少了延时,并与现有的快速切换/IPv6路由优化技术能很好地结合起来。     

Analysis and Evaluation of Mobile IPv6 Handovers over Wireless LAN

In this paper, we analyze the IPv6 handover over wireless LANs. Mobile IPv6 is designed to manage mobile nodes movements between wireless IPv6 networks. Nevertheless, a mobile node cannot receive IP packets on its new point of attachment until the handover completes. Therefore, a number of extensions to Mobile IPv6 have been proposed to reduce the handover latency and the number of lost packets. We focus on Fast Mobile IPv6 which is an extension of Mobile IPv6 that allows the use of L2 triggers to anticipate the handover. We compare the handover latency in four specific cases: basic Mobile IPv6, the forwarding method of Mobile IPv6, the Anticipated method, and the Tunnel-Based Handover. The results of the handover latency are calculated with the L2 properties of IEEE 802.11b. In particular, we take into account the L2 handover for different configurations of the wireless network.     

An adaptive hierarchical mobile IPv6 using mobility profile

The Hierarchical Mobile IPv6 (HMIPv6), which is based on the Mobile IPv6 (MIPv6), has been proposed by IETF to reduce registration control signaling. It separates micro‐mobility from macro‐mobility with the help of an intermediate mobility agent, called the mobility anchor point (MAP), and exploits a Mobile Node's (MN's) spatial locality. However, all packets from a Correspondent Node (CN) to an MN are delivered through the MAP. That causes delay in packets delivery and the congestion of packets in the MAP so that it results in deterioration of network capability. To alleviate these problems, we propose a Hierarchical Mobile IPv6 protocol using not only spatial locality but also temporal locality. We introduce a profile for management of these locality information. According to the information in the profile, some packets are directly delivered to an MN, if MN seems to reside for a long time in the current subnet. Also, we introduce a handover scheme with the help of an L2 trigger, so that the proposed scheme takes nearly the same handover delay time as HMIPv6. The other contribution of this paper is to suggest a mathematical modeling and analysis of network traffic costs, MAP processing costs and handover latency for both HMIPv6 and the proposed scheme. Copyright © 2004 John Wiley & Sons, Ltd.     

面向移动IPv6层次化网络的快速接入认证方案

提出了一个面向移动IPv6层次化网络的快速接入认证方案,从效率和安全性2个方面提高移动IPv6层次化网络接入认证的性能。首先,利用向量网络地址编码方法实现网络数据传输,提高家乡注册性能;其次,提出一种基于格的层次化签名方案,在接入认证过程中实现双向认证,提高认证过程的安全性。方案分析表明,所提出的接入认证方案具有强不可伪造性并可以抵御网络中的重放攻击,同时可以减少整个接入认证过程的延迟时间。     

A New Enhanced Fast Handover Algorithm in Hierarchical Mobile IPv6 Network

1　Introduction　MobileIPv6requirestheMobileNode (MN)toregisterwiththeHomeAgent (HA)andtheCorre spondentNode (CN)whenitchangesitspointofattachmentintheInternet[1～ 3] .Therefore ,thiscauseMobileIPv6toincurlongdelayintheregis tration process,andaddsignalingtraffictothebackbonenetworkespeciallywhentheHAandCNarefarawayfromtheMN .Inordertominimizethisdelay ,andthesignalingoverhead presentinMobileIPv6,literatures[4～7] proposeHierarchicalMobileIPv6(HMIPv6)architectureandafasthan dover…     

Predictive versus Reactive—Analysis of Handover Performance and Its Implications on IPv6 and Multicast Mobility

Handovers in mobile packet networks commonly produce packet loss, delay and jitter, thereby significantly degrading network performance. Mobile IPv6 handover performance is strongly topology dependent and results in inferior service quality in wide area scenarios. To approach seamless mobility in IPv6 networks predictive, reactive and proxy schemes have been proposed for improvement. In this article we analyse and compare handover performance and frequencies for the corresponding protocols, as they are an immediate measure on service quality. Using analytical methods as well as stochastic simulations, we calculate the performance decreases originating from different handover schemes, the expected number of handovers as functions of mobility and proxy ratios, as well as the mean correctness of predictions. In detail we treat the more delicate case of these rates in mobile multicast communication. It is obtained that performance benefits, expected from simple analysis of predictive schemes, do not hold in practice. Reactive and predictive handovers rather admit comparable performance. Hierarchical proxy environments—foremost in regions of high mobility—can significantly reduce the processing of inter–network changes. Reliability of handover predictions is found on average at about 50%.     

A FAST SEAMLESS HANDOVER SCHEME AND ITS CDT OPTIMIZATION FOR PING-PONG TYPE OF MOVEMENT

In mobile IPv6 networks, the ping-pong type of movement brings about frequent handovers and thus increases signaling burden. This letter proposes a fast seamless handover scheme where the access router keeps the mobile node＇s old reservation till the offline Count Down Timer （CDT） expires in order to reduce handover signaling and delay while the mobile node returns in a very short period of time. Based upon a poisson mobility model, an simple expression for CDT optimization is given out for the scheme to achieve the best cost performance of resource reservation.