基于OPNET的IPSec VPN的性能分析

采用OPNET仿真软件对网络性能进行仿真与分析,既可以减少统在网络设计、性能研究及开发的费用,提高网络设计的效率,又使得数据统计与分析变得非常容易。文章主要论述了网络仿真的流程、建模的方法,并通过实验利用OPNET软件对IPv6环境下IPSecVPN的性能作出详细的分析。     

基于OPNET的改进式泛洪路由仿真

本文概要介绍了改进式泛洪路由和网络仿真工具OPNET。详细讨论了如何利用OPNET工具建立改进式泛洪路由仿真模型的过程,并构建了一个基于WCDMA网络的改进式泛洪路由仿真平台。在此基础上,对改进式泛洪路由的功能和性能进行了分析和验证。     

基于IP协议的通信技术及网络仿真设计

阐述了IP网络的拓扑结构、体系结构及在IP网络上实现数据传输需考虑的技术问题,以及网络技术,介绍了网络设计和仿真工具OPNET,并给出了仿真结果。     

OPNET的网络仿真机制及仿真建模方法

随着计算机技术和通信技术的迅猛发展，网络仿真已成为时下研究、规划、设计网络不可缺少的工具。本文以OPNET为例，在系统研究OPNET网络仿真机制的基础上，着重探讨了OPNET的网络仿真建模方法。     

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IPv6的RIPng路由协议仿真分析

本文介绍了RIPng协议。利用OPNET仿真软件对RIPng与RIPv2协议的收敛速度、路由开销以及负载平衡等进行了分析。结果表明RIPng协议除了适用于IPv6之外,在其它方面类似于RIP协议。     

基于SNMP代理的IPv6网络仿真环境

提出了一种利用软件技术仿真IPv6大型网络的方法，并详细分析了采用基于IPv6的SNMP代理技术实现对IPv6大型网络环境仿真的技术需求，并对实现作了初步介绍。     

当前主要网络仿真工具研究和实践

从网络仿真产生的背景入手,介绍当前主要的网络仿真软件,重点介绍了其中的OPNET和NS2两种仿真工具,并结合一个具体的实例对两者的仿真原理、仿真效率、仿真步骤和软件的通用性等进行了比较分析。     

基于OPNET的IP试验网络性能仿真研究

应用OPNET网络仿真工具,探讨了OPNET的关键仿真技术,根据其技术特点阐述了仿真步骤,以及对试验网进行了建模、实现了对IP试验网相关网络性能的仿真,并对仿真结果进行了分析。     

用OPNET研究无线Ad Hoc的语音传输性能

探讨了用仿真工具OPNET来研究语音分组在无线Ad Hoc网络传输特性。通过用OPNET网络仿真工具分析了三种不同场景下,语音分组在无线Ad Hoc网络中传输质量的变化,及对三个不同场景下语音分组传输质量进行了分析比较,得到一些有用的结论,如：验证了用OPNET仿真工具研究无线Ad Hoc网络语音传输特性的有效性和可行性;在无线Ad Hoc网络中,随着跳数的增加,语音传送质量会随着跳数的增加而变差等有用结论。     

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.     

IPv4协议与IPv6协议的平滑过渡实施策略

鉴于IPv4的不足,论文阐述了实施IPv6的实际意义,并重点从IP地址数量、安全性、移动性、服务质量等方面研究了IPv6协议。同时也分析了IPv4协议过渡到IPv6协议的几种常用技术。通过实例模拟仿真,采用小凡模拟器组建了该网络拓扑图,使用思科7200系列路由器对隧道技术进行配置,仿真结果表明:该实验基本能够实现IPv6网络与IPv4网络的通信。     

Improving Mobile IPv6 handover and authentication in wireless network with E‐HCF

Mobile IP allows a mobile node to maintain a continuous connectivity to the Internet when moving from one access point to another. However, due to the link switching delay and to Mobile IP handover operations, packets designated to mobile nodes can be delayed or lost during the handover period. Moreover, every time a new attach point is confirmed, the mobile node, its home agent and its corresponding node must be authenticated mutually. This paper presents a new control function called Extended Handover Control Function (E‐HCF) in order to improve handover performance and authentication in the context of Mobile IPv6 over wireless networks. With an analytical model and some OPNET simulations, we show in this paper that our solution allows provision of low latency, low packet loss and mutual authentication to the standard handover of Mobile IPv6. Copyright © 2009 John Wiley & Sons, Ltd.     

Analysis of IPv6 handovers in IEEE 802.16 environment

The second generation of WiMAX solutions, based on IEEE 802.16-2005 standard, offers limited mobility support. Unfortunately, after quickly changing the point of attachment on the WiMAX data link layer (DLL), very slow and inefficient IPv6 reconfiguration takes place. Delays introduced by automatic configuration (DHCPv6 and IPv6 protocols) and Mobile IPv6 can easily diminish or even render useless all benefits gained using the efficient handover performed on DLL. As handover is a crucial process in mobile cellular environments, reasons behind delays introduced by IPv6 layer mechanisms have to be analyzed and appropriate countermeasures applied. In order to analyse influence of different factors on the handover delay a simulation environment modelling the full handover procedure in a WiMAX environment has been developed. It allows simulation and analysis of various mobility related issues, offering support for multiple base stations with groups of subscribers, both fixed and mobile, with various mobility models. Also support for tight integration with higher layers (IPv6, DHCPv6, and Mobile IPv6) is fully implemented. All stages of full IPv6 handover in IEEE 802.16 environment, focusing on major reasons of reconfiguration delays are described. The paper presents components, functional requirements and architecture of the simulation environment, together with example simulation results. The obtained results clearly show that most significant delays are caused by the IPv6 layer. The areas of improvement in several autoconfiguration mechanisms are identified. Proposals include novel use of DHCPv6 relays for remote configuration, solving DAD delays, limiting Binding Update procedure in Mobile IPv6, and configuring routing through DHCPv6 communication. A universal metric for assessing impact of every stage on handover efficiency is also defined. Several proposed improvements to the IPv6 handover process are evaluated. Discussion regarding possible generalization of best improvement proposals and remarks on further research areas conclude this paper.     

头标压缩算法在移动IPv6中的应用

无线网络的带宽相对较窄,为了解决移动IPv6分组头标开销过大问题,本文提出了移动IPv6头标压缩算法。在无线链路上仅在数据流开始的时候发送完整的分组和选项头标,后续的IPv6分组只传送头标域中的变化部分和相对同一个流的关键标识符,在无线链路的两端压缩/解压缩分组头标。该算法有较好的容错功能,有效利用了无线带宽,应用前景广阔。     

IPv6的地址结构特点与管理机制分析

本文主要介绍了有关IPv6互联网的网络地址结构及其管理机制。与现行的IPv4地址相比,IPv6在地址的长度、分类方法、表示方法和类型等方面均不同相同。它可有效地解决IP地址枯竭与路由效率低下的问题,同时具有地址聚类性、多播性、任播性和接口多址性等特点;而在IPv6地址管理方面则采用层次化路由选择策略,支持QoS路由协议,将地址解析通过领导发现协议来实现,新增了无态地址的自动配置,使得网络地址的重新编号变得更加简单快速。最后通过模拟仿真的方法,进一步分析说明了IPv6网络的性能。     

基于OPNET的无线传感器网络仿真

OPNET是目前广泛使用的可用于网络仿真及协议分析等的仿真工具软件。本文以LEACH协议为例,阐述了基于OPNET平台进行无线传感器网络协议仿真的一般过程。首先本文简要描述了LEACH协议的网络模型以及能量模型,随后介绍了利用OPNET进行LEACH协议建模的步骤。最后给出并分析了仿真结果。     

基于主动网络技术的移动IPv6切换方案

该文首先分析了IETF制定的移动IPv6协议在切换过程中所存在的缺点,然后提出一种基于主动网络技术的方案来解决这些问题,改善移动IPv6的性能.最后通过网络仿真,证明这种方案具有更 多的优点和更高的性能。     

移动IPv6管理策略与仿真的研究

文章研究了移动IPv6管理策略问题。根据层次化移动IPv6路由和控制方法，通过仿真计算与分析．得出此局部频繁切换的移动IPv6控制方法能有效减少注册、绑定更新给网络性能带来的代价，使网络性能得到改善。