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。     

一种基于MobiCast的移动IP组播方案

本文提出一种改进的MobiCast方案来实现移动IP组播通信,主要解决MobiCast方案中进行区域间切换时组播数据包丢失问题。与MobiCast方案相比,在区域外地代理(DomainForeignAgent,DFA)处引入一种缓存的机制。当移动节点发生区域间切换时,移动节点的旧区域外地代理采用隧道技术,将移动节点的信息和缓存的组播数据包发送给移动节点的新区域外地代理处,减少移动节点进行区域间切换时丢失的组播数据包。     

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切换技术

基本的移动IPv6切换时延太大,无法满足实时业务的要求。文章在分析了现有移动IPv6网络切换技术的基础上,提出了一种基于分层移动IPv6网络模型的快速切换方案F-HMIPv6。该方案实现了移动节点在不同移动锚点域移动的快速切换操作。从理论分析得出结论,该方案可以弥补现有移动IPv6网络切换技术中的一些缺陷。     

移动IP在无线局域网下的一种快速切换方法

针对移动IP在无线局域网下的应用,提出了一种新的基于链路层的移动IP快速切换方法,通过在无线局域网的无线接入点间加入特定的MAC网桥来减少移动节点在切换时产生的切换时延,进而减少移动节点上行和下行方向上的数据包的丢失,达到对移动IP切换进行优化的目的。此方法在无线局域网实际环境中进行了性能测试,结果证明优化后的时延较之原来普通移动IP切换时延有明显降低。     

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…     

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。     

移动IPv6切换时延优化新方法

移动IPv6中,移动节点(MN)在不同子网间移动时,既不中断与通信对端(CN)的通信,也不用改变其本身的IP地址.但是当MN与其家乡代理(HA)之间相距较远时,移动IPv6切换时延较大,对于实时性要求较高的业务无法适用.本文分析比较了目前移动IPv6常用的切换时延优化方法,提出了一种自适应快速层次移动IPv6切换时延优化方法,减小了移动IPv6切换时延,提高了网络的性能.     

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.     

Multicast Handoff Agent Mechanism for All-IP Mobile Network

This paper proposes a mechanism called a Multicast Handoff Agent (MHA) to reduce handoff latency for IP multicast. The MHA acts as a proxy for the Internet Group Management Protocol (IGMP) of mobile nodes and keeps information for members of multicast groups in a cell. When a mobile node moves to other cell, the MHA immediately sends unsolicited reports without waiting for the IGMP query. In addition, our mechanism may conserve battery power since it does not need to reply to a query.The mechanism is evaluated through simulation and analysis and compared with the IGMPv2 for mobility and IGMP traffic. Simulation results show that handoff latency can be largely reduced and the IGMP control traffic can be eliminated on the wireless links during the duration of membership.     

一种基于移动IPv6协议的软切换实现方案

移动IPv6协议解决了IPv6网络中移动节点的位置更新和路由可达问题,使移动节点能够在不同IPv6子网间进行切换而不中断当前连接。但是这种切换的时延较长,影响移动IPv6网络的性能。为了减少切换时延,文章在移动IPv6协议中引入软切换技术,提出一种采用绑定更新计时器和路由优先级变换机制的软切换工程实现方案,实验结果表明,该软切换方案可以有效提高移动IPv6网络的性能。     

基于IPv6的快速切换改进方案

在移动IP网络中,当前的移动性管理方案由于其基本协议的切换时延较大、丢包率较高而不能适应实时业务和移动通信的要求,所以需要改善移动性管理策略的切换性能,尽量实现无缝切换和零丢包率。提出了一种基于移动IPv6的快速切换的改进方案,采用一种新的地址分配方式使得移动节点能够在移动至新的网络后迅速获取新的转交地址,有效地减少了切换所产生的时延和丢包率,具有较好的切换性能。     

有/无线ATM网的组播选路算法

本文提出一种组播选路算法,在组播连接路由树的代价函数中计入了移动成员的越区切换发生概率,使为移动成员服务的接入节点（ＡＰ）尽可能成为组播路由树的树叶节点。当移动成员发生越区切换以后,可减去原来为之服务的ＡＰ和相应的树枝通道链路,从而保证了网络资源得以有效地利用。数值模拟分析的结果表明,我们提出的算法达到了这一目的。     

A Simple and Robust Vertical Handoff Algorithm for Heterogeneous Wireless Mobile Networks

Wireless networking is becoming an increasingly important and popular way of providing global information access to users on the move. One of the main challenges for seamless mobility is the availability of simple and robust vertical handoff algorithms, which allow a mobile node to roam among heterogeneous wireless networks. In this paper, motivated by the facts that vertical handoff procedure is done on mobile nodes and battery power may be one crucial parameter for certain mobile nodes, a simple and robust two-step vertical handoff decision algorithm is proposed for heterogeneous wireless mobile networks. To the best of our knowledge, this is the first vertical handoff algorithm that takes the classification of mobile nodes into consideration, one is resource-poor mobile nodes, and the other is resource-rich mobile nodes. This new feature makes it more applicable in the real world. In addition, dynamic new call blocking probability is firstly introduced by this paper to make handoff decision for wireless networks. The experiment results have shown that the proposed algorithm outperforms traditional algorithms in bandwidth utilization, handoff dropping rate and handoff rate.     

一种基于无线局域网的移动检测优化方案

无线局域网采用移动IP实现移动性管理.移动IP切换存在切换时延大,数据包易丢失的问题.切换时延由移动检测时延和注册时延组成,而移动检测时延在其中占主要部分.文章提出了一种移动检测优化方案,采用了自适应绑定的算法,同时充分考虑了域内小范围高频度切换的情况,使移动节点在无线局域网环境中进行快速有效的切换.     

A Low Cost Route Optimization Scheme for Cluster-Based Proxy MIPv6 Protocol

Proxy Mobile IPv6 (PMIPv6) is a network based mobility protocol which has been designed to relieve the mobile nodes (MNs) from participating in the mobility process and to reduce the long handoff latency of the MIPv6 protocol. However, PMIPv6 incurs a long communication path due to the triangle routing problem, in which, all packets sent by MNs are obligated to pass through the local mobility anchor. Several solutions have been proposed to mitigate this issue. However, they still incur high signaling overhead to recover the Route Optimization (RO) status after handoff. In this paper, we propose a Cluster-Based RO (CBRO) scheme for the clustered architecture of the PMIPv6, in which, the Mobile Access Gateways (MAGs) are grouped into clusters with a distinguished Head MAG (HMAG) for each. In the proposed CBRO, the RO process is relied on the HMAGs to reduce the handoff latency while achieving a fast recovery of the optimized path after handoff. The proposed CBRO is evaluated analytically and compared with the basic PMIP and the current RO schemes. The obtained numerical results have shown that the proposed CBRO outperforms all other schemes in terms of signaling cost required to recover the RO status after handoff and the total cost performance metrics.     

A Secure Relay-Assisted Handover Protocol for Proxy Mobile IPv6 in 3GPP LTE Systems

The LTE (Long Term Evolution) technologies defined by 3GPP is the last step toward the 4th generation (4G) of radio technologies designed to increase the capacity and speed of mobile telephone networks. Mobility management for supporting seamless handover is the key issue for the next generation wireless communication networks. The evolved packet core (EPC) standard adopts the proxy mobile IPv6 protocol (PMIPv6) to provide the mobility mechanisms. However, the PMIPv6 still suffers the high handoff delay and the large packet lost. Our protocol provides a new secure handover protocol to reduce handoff delay and packet lost with the assistance of relay nodes over LTE networks. In this paper, we consider the security issue when selecting relay nodes during the handoff procedure. During the relay node discovery, we extend the access network discovery and selection function (ANDSF) in 3GPP specifications to help mobile station or UE to obtain the information of relay nodes. With the aid of the relay nodes, the mobile station or UE performs the pre-handover procedure, including the security operation and the proxy binding update to significantly reduce the handover latency and packet loss. The simulation results illustrate that our proposed protocol actually achieves the performance improvements in the handoff delay time and the packet loss rate.     

基于802．11协议的无线局域网快速切换研究

快速切换是移动管理研究中的重要问题之一,对实现移动终端上的多媒体等实时应用具有重要的意义.综述了基于802.11协议的无线局域网快速切换的研究进展,分析了切换的过程和快速切换的影响因素,并对快速切换研究工作进行了介绍,最后总结了研究现状中存在的问题以及需要进一步研究的工作.