NEMO移动网络及其路由优化技术

网络移动（Network Mobility,NEMO）主要研究子网作为一个整体在全球互联网范围内移动过程中存在的网络可达性、效率和安全等方面的问题。本文介绍了NEMO基本支持协议以及嵌套NEMO网络的模型。在此基础上分析了当前几种嵌套NEMO网络的路由优化方案存在的问题,并给出了一个改进的路由优化方案。最后总结了当前NEMO网络部署中存在的问题。     

A secure and efficient batch binding update scheme for route optimization of nested NEtwork MObility (NEMO) in VANETs

NEtwork MObility (NEMO) is designed to efficiently deal with the mobility of a set of mobile nodes using Mobile Routers (MRs). NEMO is extremely suitable for Vehicle Ad hoc NETworks (VANETs) due to its highly mobile nature. However, NEMO also suffers from some limitations such as inefficient routing paths and multiple tunnels. To solve the problem of inefficient routing paths, there is a growing need for better route optimization. To achieve route optimization in NEMO, when a mobile router moves into a new foreign network, the MR or the mobile nodes within this MR are required to submit binding update messages to the correspondent nodes connecting with the aforementioned mobile nodes. As a result, a popular correspondent node may simultaneously receive a great number of binding update messages within a short period of time. This problem is quickly exacerbated in a nested NEMO environment. In addition, the security issues for route optimization have been widely discussed. Most of the improved schemes adopt traditional signatures to solve the security problems for route optimization, which often leads to heavy computational costs when a large number of signatures need to be verified. In this paper, we propose a Batch Binding Update Scheme (BBUS) to verify multiple signatures at the same time. By the adoption of elliptic curve cryptography, both the computational and communication costs are significantly reduced.     

Cellular universal IP for nested network mobility

In recent years, network mobility (NEMO) has been studied extensively due to its potential applications in military and public transportation. NEMO basic support protocol (NBSP), the current de facto NEMO standard based on mobile IPv6, can be readily deployed using the existing mobile IPv6 infrastructure. However, NBSP’s root in mobile IPv6, such as the need of care-of address (CoA) and tunneling, results in substantial performance overhead, generally known as route sub-optimality, in nested NEMO environments. This paper tackles this problem by proposing a scheme based on cellular universal IP (CUIP) to eliminate the need for CoA and tunneling in supporting nested network mobility. Using quantitative analysis, we show that the proposed scheme outperforms the existing nested NEMO schemes by multiple folds in terms of bandwidth overhead. We also show how IP fragmentation negatively impacts route optimality, and that the proposed scheme is inherently superior to the existing schemes in this regard. More importantly, while the scalability of the existing schemes generally deteriorates with the network size, the complexity of our proposed scheme is independent of the network size and thus is far more scalable. Our results show that the proposed scheme is particularly suitable for nested NEMO networks formed by mobile routers with random and ad hoc movement patterns.     

ROAD+: Route Optimization with Additional Destination-Information and Its Mobility Management in Mobile Networks

In the NEtwork MObility(NEMO) environment,mobile networks can form a nested structure.In nested mobile networks that use the NEMO Basic Support(NBS) protocol,pinball routing problems occur because packets are routed to all the home agents of the mobile routers using nested tunneling.In addition,the nodes in the same mobile networks can communicate with each other regardless of Internet connectivity.However,the nodes in some mobile networks that are based on NBS cannot communicate when the network is disc...     

嵌套移动网络中的路由优化研究

针对嵌套移动网络内部节点间通信的乒乓路由问题,提出一种基于绑定更新的路由优化方案。该方案利用绑定更新报文所携带的信息构筑嵌套域内移动路由器的路由信息,实现了嵌套移动网络内部移动路由的功能,有效解决乒乓路由问题,避免由于隧道嵌套而造成的带宽浪费。实验结果表明该方案是可行的。     

嵌套NEMO中的路由优化方案研究

针对嵌套NEMO中存在的乒乓路由和数据包多层封装问题进行深入分析,提出一种嵌套NEMO的优化方案,改变NEMO中传统的MR嵌套转发报文的做法,使得MR的HA能够将发送到MR的数据直接重定向到整个嵌套NEMO所连接的外地网络,减少了嵌套的次数,并使得小范围的切换更新报文能控制在NEMO内部,减少了切换时延。分析表明,与NEMO基本支持协议相比,方案有效地解决了NEMO路由优化问题,提高了数据包的传输效率。     

6LoWPAN嵌套移动网络路由优化方案*

提出一种6LoWPAN嵌套移动网络路由优化方案,在此方案中,6LoWPAN移动网络节点无须经过家乡代理也无须建立隧道即可与通信节点通信,节省了数据传输开销,缩短了数据传输延迟。提出了移动路由器转交地址的分层结构,根据此分层结构,提出了基于最短路径的移动路由器转交地址配置算法,缩短了数据传输延迟。从理论和仿真两个角度对所提出的路由优化方案的路由优化开销、路由延迟及路由代价等性能参数进行了比较分析,分析结果验证了本方案的有效性和高效性。     

Intra domain route optimization for ubiquitous network

The main advantage of a wireless network is user mobility, which calls for efficient routing support at the network layer. An architecture combines hierarchical mobile IPv6 and network mobility for a network mobile and mobile nodes move in tandem and make a hierarchy in the wireless network to management of micro-mobility and seamless handoff. But the capability of the architecture for intra domain route optimization is impaired. So we propose functionality in domain nodes to enable intra domain path optimization for ubiquitous network. It is shown that intra domain cost effect is beneficial in every hierarchical domain that spans mesh network topology. We address the key function for our proposed scheme and analyze the usefulness of our proposed method using mathematically. We show that our proposed scheme performs much better than Network Mobility protocol, especially when the number of mobile nodes or mobile routers or correspondent nodes increases in hierarchically nested in ubiquitous networks.     

Evaluation of MANEMO route optimization schemes

In the doorway of the Mobile IPv6 (MIPv6), it was considered as the standard protocol that support the host mobility. Due to its limitation that does not support the mobile routers (MRs), the Internet engineering task force (IETF) has introduced the NEMO basic support (NEMO BS) protocol. The mobile ad hoc network (MANET) routing protocol provides the local and the direct communications between two mobile devices within the nested NEMO (when multiple MRs are connected together). Integrating the MANET and the NEMO (MANEMO) provides the necessary additions to the existing protocols (IPv6, neighbor discovery (ND), and NEMO) to support the nested MRs. It provides a mechanism to select the most suitable path to the Exit Router (ER) as a default in the MANEMO Fringe Stub (MFS). The NCM (NEMO centric MANEMO) protocol is introduced to address the nested NEMO issues (e.g. pinball problem) by using the MANET routing a protocol (i.e., OLSR), while the MCM (MANET centric MANEMO) protocol is introduced to address the MANET problem (e.g. Internet connectivity). The main aim of this paper is to investigate the current approaches that are introduced to provide the route optimization (RO) for the NEMO. It highlights the strengths and the limitations of these approaches. Both the qualitative and the quantitative evolutions of these proposals are hereby presented.     

基于HMIPv6的民用航空移动网络设计及实现

当一个移动节点(MN)或移动路由器(MR)移动到另一个移动网络,并通过另一个MR提供接入时,这样的情况称为嵌套移动网络,这样的嵌套可以有很多层。一个典型的例子是携带笔记本电脑的乘客登上一架通过MR提供移动网络服务的航班,并通过该MR访问互联网或公司的内部网络。在这种情况下,移动节点和通信节点之间的数据包的传送路径将到达每个节点的HA(家乡代理)处,因此其路径将比基本的MIP(移动IP)长得多,现有路由优化方法不能解决这个问题,因为可以旁路MN的HA,但是却无法跳过MR的HA。本文通过在民航移动网络的设计中应用HMIP(层次移动IP)思想,并对其进行一定的改进来解决上面的这些问题,提高网络的运行效率。     

Experimentation and performance analysis of multi-interfaced mobile router scheme

Network mobility (NEMO) aims providing seamless Internet connectivity of the whole mobile network that consists of mobile routers (MRs) and mobile network nodes (MNNs). The network moves around along with vehicles as a whole. According to NEMO basic support protocol (NEMO BSP), only one primary care of address (CoA) of MR can be registered with home agent, which will affect the handover performance. As an extension of NEMO BSP, multiple care of addresses (MCoA) registration scheme was proposed as Internet-draft and has received extensive researches.This paper studies the Internet connectivity of mobile router (MR) on the basis stated above; MR is equipped with WLAN, CDMA and GPRS interfaces simultaneously. Concretely, a smooth handover algorithm is proposed and experimented on our platform successfully; round trip time (RTT) of each link and the handover process between different interfaces are analyzed, respectively. Furthermore, the service disruption time and packet loss ratio performances are also compared between uni-interfaced MR scheme of NEMO BSP and scheme proposed in this paper, and the results indicate that multi-interfaced scheme not only supports large area movement across heterogeneous networks of MR, it also provides a seamless handover with no packet loss and little service disruption time.     

一种移动IP的外部代理分层模型--Step-HMIP

现有的移动IP规范存在两个重要的性能问题：(1)通信对端和外地链路上的移动节点之间的三角路由问题;(2)移动节点在紧密耦合的小蜂窝基站间频繁切换时会增加网络负载并加重数据包的丢失．该文针对这两个问题进行研究,给出了一个基于基本移动IP规范的外部代理分层模型——Step-HMIP模型．在此模型中引入了一个新的实体——网关移动代理,用以实现优化路由和平滑切换的功能：在NS上建立了Step-HMIP的仿真模型,对模型的主要参数测试结果表明．Step—HMIP模型在对属地代理(HA)、固定的通信对端(如Web服务器和FTP服务器)和对网络层以上协议无需进行改动的情况下．以小的配置代价就可显著优化路由,降低属地代理的注册负载和稳定了切换时的数据传输率．     

A Secure Correspondent Router Protocol for NEMO Route Optimization

The Network Mobility (NEMO) protocol is needed to support the world-wide mobility of aircraft mobile networks across different access networks in the future IPv6 based aeronautical telecommunications network (ATN). NEMO suffers from the constraint that all traffic has to be routed via the home agent though. The already existing correspondent router (CR) protocol solves this triangular routing problem and permits to route packets on a direct path between the mobile network and the ground based correspondent nodes. We identify security deficiencies of this protocol that make it unsuitable for use within the ATN. We therefore propose a new route optimization procedure based on the CR protocol that provides a higher level of security. We evaluate our new protocol in three ways. We first conduct a simulation based handover performance study using an implementation of a realistic aeronautical access technology. We then investigate the mobility signaling overhead. Finally, we specify a threat model applicable for the aeronautical environment and use it to perform a security analysis of both the old and our new protocol. It is shown that our protocol is not only more secure but also provides better handover latency, smaller overhead in the aeronautical scenario and a higher level of resilience when compared to the original CR protocol.     

Solving pinball routing,race condition and loop formation issues in nested mobile networks

In order to manage the mobility of Mobile Network, IETF has specified NEMO protocol. However, the standard NEMO solution does not specify any Route Optimization mechanism, as a result of which the data is always exchanged over a bi-directional tunnel maintained between the MNet and its respective Home Agent. This in-efficient routing of packets imposes several performance issues that gets compounded for nested Mobile Networks, where data packets will be tunneled/detunneled multiple times undergoing repeated levels of encapsulations/decapsulations. Such routing of packets, commonly termed as pinball routing, is considered a serious performance limitation and its adverse effect is maximum during intra-nest communication, i.e., between two inter-communicating nodes existing within the same MNet domain. Another issue concerned with nested mobile networks is loop formation and race condition between two competing Mobile Routers.Previously, we had proposed a basic RO solution called NERON. In this paper we extend the base NERON protocol solution to solve issues due to Pinball routing phenomena, and to avoid loop formation and race condition between contending Mobile Routers.     

基于双向直通隧道机制的移动IP路由优化方法

通过引入一个增强型通信代理,与归属代理和外区代理合作,提出了一种WLAN环境下的移动IP路由优化方法：支持子网优化和绑定优化的双向直通隧道机制,提高了移动IP的路由有效性,并减少了移动节点的切换延时,还分析了入口过滤机制对该路由优化技术的影响及相应对策。     

移动式网络的动态家乡代理协议

为了减轻移动式网络中的三角路由问题,引入一个动态家乡代理为外地的移动式网络提供本地家乡代理的服务。设计了基于AAA机制的动态家乡代理模型,实现了基于数字签名原则和D-H密钥交换算法的移动式网络注册和密钥协商协议,描述了移动式网络节点的数据路由方式。安全性分析表明,动态家乡代理协议安全地实现了移动路由器与动态家乡代理之间的密钥交换,有效防止了中间人攻击和会话拦截攻击,能对实施泛洪攻击的移动节点进行跟踪。     

嵌套移动网络中基于位置更新的隧道MTU发现机制

针对嵌套移动网络中的最大传输单元(MTU)问题,在分析现有方案不足和网络结构特点的基础上,建立了隧道MTU模型,提出一种基于位置更新的隧道MTU发现机制。该机制在家乡代理存储相互间的路径MTU值,利用路由器通告、绑定更新等信令消息携带MTU信息,在位置更新过程中实现了节点对隧道MTU的快速安全跟踪,并适用于多穴配置和多种路由优化方案。仿真分析表明,相比现有方案,该机制能够降低报文延迟和传输开销,提升带宽利用率。     

NEMO网络在PMIPv6中的实现及快速切换方案

针对网络移动性（NEMO）基本支持方案（NBS）中NEMO网络切换时延过长的问题,提出一种NEMO网络在代理移动IPv6（PMIPv6）中的实现方案,并针对其切换流程进行了进一步优化。新方案通过缩减经无线链路传输的切换信令条数以及提前建立数据转发隧道,实现了移动网络的快速切换。分析结果显示,新方案的标准切换流程和快速切换流程比NBS方案的切换流程分别减少了56.55%和58.63%的切换时延。     

一种无线Mesh网络中可证明安全的HMIPv6路由优化方案

HMIPv6技术能够实现无线Mesh网络的无缝切换,针对其绑定更新过程中执行路由优化存在的安全问题,提出了一种适用于无线Mesh网络的基于椭圆曲线公钥自认证体制的安全路由优化方案。该方案使用户在执行路由优化的过程中能够实现对绑定更新消息的认证与授权,且通过有效的会话密钥协商机制为绑定更新消息的传输提供了安全保障,具有可证明安全性。最后通过性能分析表明,该方案简化了标准路由优化方案的流程,提高了一般注册过程的效率。     

移动IPv6路由优化模型的性能分析和适应性策略

移动IPv6中为解决三角路由(triangle routing,简称TR)问题,采用路由优化(route optimization,简称RO)作为缺省方案.但是,路由优化在减小路由开销的同时引入了新的信令开销,因此,并非在任何情况下路由优化都优于三角路由.目的是对比在不同网络条件下路由优化和三角路由的开销,提出更有效的适应性路由优化策略.采用数学模型进行分析,引入数据到达率、移动切换率及MN(mobile node)和HA(hone Agent),CN(correspondent node)的位置关系等关键参数,得到分别采用RO和TR的总开销的表达式;引入数据到达率和移动率比值(packet-to-mobility,简称PMR)、节点间距离的关系来权衡数据和信令开销,得到总开销随相关参数变化的数值结果;基于这些分析提出了PMRRO(packet-to-mobility route optimization)适应性路由优化策略:以总开销的最小化为目标,以PMR阈值作为指标,通过适应性调整来决策MN和CN之间的路由选择.模拟验证表明,该策略有比单纯采用TR和RO更好的性能,是为移动管理减少开销、提高效率提出的可行方案.