IP multicast for mobile hosts

We present alternative designs for efficiently supporting multicast for mobile hosts on the Internet. Methods for separately supporting multicasting and mobility along with their possible interactions are briefly described, and then various solutions to the combined problem are explored. We examine three different multicast delivery mechanisms and compare them based on their efficiency and impact on host protocol software. We describe proposals for integrating multicasting and mobility in the Internet architecture. We first present IP extensions for host mobility and other extensions for multicasting. We then examine local multicasting mechanisms, focusing on a group membership protocol that is optimized for wireless point-to-point links. Next, we examine the problems of sending and receiving multicast datagrams in a wide area network. For multicast reception, we describe three alternative proposals and compare them by examining both their applicability and their performance, as well as possible tradeoffs among the two     

IPv6对移动IP的支持

ＩＰｖ６是下一代的互联网协议,它最终将取代目前使用的ＩＰｖ４成为互联网的主要网络层协议。移动ＩＰｖ６目前是ＩＥＴＦ（Ｉｎｔｅｒｎｅｔ Ｅｎｇｉｎｅｅｒｉｎｇ ＴａｓｋＦｏｒｃｅ）移动ＩＰ工作组议程中的主要课题。移动ＩＰｖ６的文件发展得很快,本文只讨论基于移动ＩＰｖ６文件的第二版本。 ＩＰｖ６和ＩＰｖ４的区别 ＩＰｖ６与ＩＰｖ４有许多重要大的区别,其中最大的两个区别是：（１）地址长度（ＩＰｖ６为１２８比特,而ＩＰｖ４为３２比特）;ＩＰｖ４报头中许多不常用的域被从ＩＰｖ６报头中删除了,放入了可选项和报头…     

Low-latency mobile IP handoff for infrastructure-mode wireless LANs

The increasing popularity of IEEE 802.11-based wireless local area networks (LANs) lends them credibility as a viable alternative to third-generation (3G) wireless technologies. Even though wireless LANs support much higher channel bandwidth than 3G networks, their network-layer handoff latency is still too high to be usable for interactive multimedia applications such as voice over IP or video streaming. Specifically, the peculiarities of commercially available IEEE 802.11b wireless LAN hardware prevent existing mobile Internet protocol (IP) implementations from achieving subsecond Mobile IP handoff latency when the wireless LANs are operating in the infrastructure mode, which is also the prevailing operating mode used in most deployed IEEE 802.11b LANs. In this paper, we propose a low-latency mobile IP handoff scheme that can reduce the handoff latency of infrastructure-mode wireless LANs to less than 100 ms, the fastest known handoff performance for such networks. The proposed scheme overcomes the inability of mobility software to sense the signal strengths of multiple-access points when operating in an infrastructure-mode wireless LAN. It expedites link-layer handoff detection and speeds up network-layer handoff by replaying cached foreign agent advertisements. The proposed scheme strictly adheres to the mobile IP standard specification, and does not require any modifications to existing mobile IP implementations. That is, the proposed mechanism is completely transparent to the existing mobile IP software installed on mobile nodes and wired nodes. As a demonstration of this technology, we show how this low-latency handoff scheme together with a wireless LAN bandwidth guarantee mechanism supports undisrupted playback of remote video streams on mobile stations that are traveling across wireless LAN segments.     

移动IP的移动性协议及管理机制

本主要从移动网络协议结构开始，讨论移动IP有关现行的和将来的Inernet移动性协议极其管理机制。     

Transparent IP radio access for next-generation mobile networks

Advances in network architecture, enhancements in signaling protocols, provisioning of end-to-end QoS, worldwide seamless mobility, and flexible service provision are among the major research challenges toward next-generation wireless networks. The integration and interoperability of all these technologies, along with new truly broadband wireless innovations and intelligent user-oriented services will lead toward the so-called 4G wireless networks. In this article we identify the key issues of an innovative transparent IP radio access system that targets 4G networks.     

区域注册移动IP中的分布式位置管理方案

提出了一种区域注册移动IP的分布式位置管理方案。该方案基于区域网络逻辑上分层的结构特点,提出了在流量负载不超出一定流量门限的前提下,为移动节点选取不同层次上的外地代理FA作为网关外地代理GFA。通过对一种区域网络模型的研究,分析了不同层次上的FA作为GFA时的信令开销。最后通过仿真计算得出了采用分布式位置管理方案时区域注册移动IP信令开销的数值结果。通过分析比较说明该方案相比于区域注册移动IP而言,可以节约10％以上的信令开销,并将有效流量分配山多个GFA承担,当某个GFA失效时将不会影响其它GFA工作,提高了网络的稳健性。     

公用无线IP移动局域网

未来Internet的应用应包含Internet话音、视频多播和交互式多媒体业务，其基本要求为高速率和低时延，即使第三代蜂窝移动通信网也不能全部满足这些业务要求。目前，迅猛增长的Internet业务和不断发展的无线技术激发了蜂窝移动通信系统和无线LAN(WLAN)接入系统的结合,给移动用户提供接入Internet和基于位置的业务。WLAN与有线网结合可以低成本、高容量和易升级方式接入Internet，而现有的WLAN接入系统的主要缺点是无线接口单一和缺少公众用户接入，从而限制了业务的扩展。基于IP的公用接入移动LAN（PamLAN，Public Access Mobi…     

SCADA系统基于TCP/IP的实时通信

在分析了SCADA系统通信机与工作站之间数据通信特性的基础上，就TCP与UDP的传输特性进行了讨论并就提高SCADA系统基于TCP／IP通信的实时性给出了结论。     

IP网实时业务服务质量问题的研究

分析了ＩＰ电话／传真业务对于服务质量的要求,对解决 其服务质量问题做了较深入的分析和探讨。列出了应用 层可采取的提高服务质量的方法,并详细分析了国际上 解决网络服务质量的两大研究模型： ＲＳＶＰ和 ＤＩＦＦ－Ｓｅｒｖ 的技术内容和优缺点。提出Ｄｉｆｆ－Ｓｅｒｖ才是解决网络服务 质量问题的研究方向。     

Real-time channel emulation for mobile communcation test beds

This article describes a methodology to model in real-time the channel quality variations for mobile communication systems. This method was used to implement a GSM hardware test bed employed to demonstrate the improved perceived voice quality obtained with link adaptation. Real-time operation is achieved by use of a large error pattern database, derived for time varying channel models. The modular design of the demonstrator and the reusability of the database enable a relatively straightforward extension to conduct novel multi-channel link level investigations. The proposed methodology can be adapted for a range of radio interfaces.     

Real-time road edge following for mobile robot navigation

The authors describe the ongoing research at the University of Bristol to explore mobile robot road-following algorithms and suitable hardware architectures to run these algorithms. The prototype hardware, designed and built at the University, is a real-time frame grabber system based on transputers. Two approaches to real-time road edge following that have been tested to guide a small tracked vehicle around the paths of the University gardens are described     

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。     

实时IP传真技术及实现

IP技术正在改变全球的通信方式。IP网,特别是Internet的飞速发展使得使用IP网络作为收发传真的传输媒体成为可能。分析了基于T.38建议的实时IP传真技术,阐述了其与存储转发IP传真技术的区别,介绍了其应用模型,并对其实现过程中的协议选择、网络丢包、抖动等难点技术进行了探讨。     

A comparison of different paging mechanisms for mobile IP

This paper proposes two Individual paging schemes, then presents a comparative analysis on the signaling cost functions of Mobile IP (MIP) with different paging protocols and paging schemes and investigates constructing optimal paging areas using discrete system model as a mobility model. In wireless mobile Internet, mobile hosts often visit foreign networks that might be far away from their home networks and the occurrences of their inter-domain movement are relatively rare. In this scenario, our analytical results show that paging, particularly individual paging, can significantly improve the total signaling cost of MIP. We show that Domain paging can bring about considerable cost saving compared to FA (Foreign Agent) paging. Our results also demonstrate the significant advantages of Individual Paging over Static Aggregate Paging. The results show that specifying the optimal paging area size is critical in saving signaling cost of MIP with paging support. Hung Tuan Do received the B.E. degree in Electrical Engineeing and Computer Science from Hanoi University of Technology, Vietnam, and the M.E. and the Ph.D. both from Gunma University, Japan. His research interests include Mobility Management, Wireless Internet and Mobile Ad hoc Networks. Yoshikuni Onozato is a Professor with Gunma University. His research interests are in satellite systems, computer communication networks and distributed computing systems and span the entire spectrum from the design and performance evaluation of these systems to their implementation. He is a member of IEEE, ACM, IPSJ, ORSJ and IEICE.     

Reliable and efficient multicast protocol for mobile IP networks

To provide a multicasting service, several multicast protocols for mobile hosts (MHs) have been proposed. However, all of these protocols have faults, such as non‐optimal delivery routes and data loss when hosts move to another network, resulting in insecure multicast data transmissions. Thus, this paper presents a new reliable and efficient multicast routing protocol for mobile IP networks. The proposed protocol provides a reliable multicast transmission by compensating the data loss from the previous mobile agent when a MH moves to another network. In addition, an additional function allows for direct connection to the multicast tree according to the status of agents, thereby providing a more efficient and optimal multicast path. The performance of the proposed protocol is confirmed based on simulations under various conditions. Copyright © 2008 John Wiley & Sons, Ltd.     

Dynamic hierarchical mobility management strategy for mobile IP networks

One of the major challenges for the wireless network design is the efficient mobility management, which can be addressed globally (macromobility) and locally (micromobility). Mobile Internet protocol (IP) is a commonly accepted standard to address global mobility of mobile hosts (MHs). It requires the MHs to register with the home agents (HAs) whenever their care-of addresses change. However, such registrations may cause excessive signaling traffic and long service delay. To solve this problem, the hierarchical mobile IP (HMIP) protocol was proposed to employ the hierarchy of foreign agents (FAs) and the gateway FAs (GFAs) to localize registration operations. However, the system performance is critically affected by the selection of GFAs and their reliability. In this paper, we introduce a novel dynamic hierarchical mobility management strategy for mobile IP networks, in which different hierarchies are dynamically set up for different users and the signaling burden is evenly distributed among the network. To justify the effectiveness of our proposed scheme, we develop an analytical model to evaluate the signaling cost. Our performance analysis shows that the proposed dynamic hierarchical mobility management strategy can significantly reduce the system signaling cost under various scenarios and the system robustness is greatly enhanced. Our analysis also shows that the new scheme can outperform the Internet Engineering Task Force mobile IP hierarchical registration scheme in terms of the overall signaling cost. The more important contribution is the novel analytical approach in evaluating the performance of mobile IP networks.     

移动IP的QoS保障

移动IP存在的问题一个是三角形路径问题。移动IP协议执行时常会遇到三角形路径问题,即通信节点发送数据包到移动节点时,需要通过其归属代理,而移动节点根据标准IP路由规则将数据包直接发送到通信节点。三角形路径问题会引起一些潜在的危害,例如增加引入流量的时延容易引起归属代理处的路由瓶颈。如果通信节点知道移动节点的转交地址,通信节点就能通过隧道技术直接发送数据包到移动节点,不需要归属代理的帮助。现在的问题是,Internet上的通信节点一般不能提供接收和存储移动节点转交地址的信息,也就是不能执行任何隧道技术。对基本移动IP…     

Hop-by-hop toward future mobile broadband IP

We try to give some perspectives on likely trends in future wireless broadband networking. The treatment is an exploration of some technologies; due to the requirement to cover the topic from a broad perspective, it is not possible to go into technical details. We review current developments toward future mobile broadband networks, and then present the 4G paradigm of trying to combine heterogeneous networks, both cellular wireless hotspots and sensor networks, together with Internet protocols. We show how different networks play their own roles in the emerging infrastructure so that we can hop by hop wave the broadband network from mobile devices toward the fiber optic core network.     

在基于MPLS的层次化移动IP网络中支持DiffServ的研究

MPLS支持DiffServ、流量工程,能为网络提供较好的QoS保证,而移动IP(MIP)能为移动设备提供较好的移动性支持。文章探讨了在无线接入网中MPLS和MIP结合实现DiffServ的方案,并给出了一种在基于MPLS的层次化MIP网络结构中支持DiffServ的体系结构,设计了其节点功能模型和关键协议。方案中利用了层次化结构的区域注册和重路由机制,减少了切换时延和网络的信令负荷。