VPN技术在IP组播视频会议系统中的应用

 针对IP组播视频会议系统在共网上部署应用时出现的安全性差、费用高、IP组播路由器资源有限等问题,提出在Internet上应用VPN技术来实现IP组播视频会议系统的解决方案,并介绍了系统的VPN网络结构和实施方法.同时,还对VPN技术的基本概念、关键技术及其特点和IP组播视频会议系统的总体设计作了简单阐述.最后在广域网上对该会议系统进行了测试.测试结果表明,实现了在广域网上运行IP组播会议系统,并有效地保证会议数据传输的安全性和可靠性.     

浅议IP组播技术在视频中的应用

IP组播技术实现IP网络中点到多点的高效数据传送。因为组播能够有效地节约网络带宽、降低网络负载,所以在实时数据传送、多媒体会议、数据拷贝、游戏和仿真等诸多方面都有广泛的应用。介绍组播的基本概念、组播地址的分配以及目前通用的组播协议;流媒体的基本概念、流媒体系统的组成;并结合大学的校园网,利用IP组播实现现场直播。     

网络拓扑结构对IP组播效率影响的研究

研究了不同网络拓扑结构对IP组播效率的影响,给出了一种度量组播效率的方法,并进行了分析与仿真.结果表明:在随机选择组播树根节点的情况下,平均节点度越大的网络,组播效率越低;限制组播路由的通过性和适当选择组播根节点的位置能够有效提高组播效率;有源最短路径树在不同网络拓扑下的性能差异较大,并且不是一种能够适合于各种网络结构的高效组播树构建算法.     

基于IPv6的PIM-SMv2协议的设计与实现

在新一代互联网中,支持组播已成为对路由器的基本要求。PIM-SM是一个不依赖于某一特定单播路由协议的组播路由协议,为组播数据转发提供路由信息。本文介绍了高性能：IPv6路由器协议栈软件中基于原始套接字(Raw Socket)通信机制的PIM—SMv2协议的设计与实现,并搭建实验环境对实现的系统进行了测试。实验结果表明,该系统已具备IPv6组播功能。     

解决ipv6中的组播与泛播

所谓组播就是指定范围的广播,比如说netmeeting就是组播的应用.而泛播是则是v6的概念,主要是指在同一个自治系统内的广播,它比较特殊,它要求所有的路由器记录源地址.对ipv6中的组播和泛播从各方面进行分析和阐述,希望使读者对ipv6中的这两种特殊的广播形式有更深的理解.     

基于分布式资源管理的DiffServ组播策略

针对区分服务(DiffServ)和组播直接结合所产生的可扩展性问题、被忽视的预留子树问题和异构组播组问题,提出了一种基于分布式资源管理的区分服务组播策略(DMSBD).新方案采用由边界节点对DiffServ域内资源进行分布式管理的方式,申请加入组播组的新成员必须通过接纳控制审核才能享有合法的优先级,同时采用接收方驱动的思想建立一套服务质量请求信令机制,并通过使用重标记的方法使组播数据流的转发节点明确知晓新成员的服务质量请求.仿真结果表明该方案能够有效地解决或缓解区分服务和组播结合时所产生的几种问题.     

基于动态代理选择的移动网络组播

针对移动网络组播面临的接入点间切换造成组播树频繁重构的问题,提出了一种新的移动网络组播方法DMA(Dynamic Multicast Agent)。DMA在远程加入的基础上,使用动态选择组播代理和局部隧道的方法,为移动网络内的节点提供组播服务。分析与仿真结果表明,DMA不但减少了因移动网络附着点改变而造成的组播树重构次数,在一定程度上屏蔽了移动网络的移动性对组播树造成的影响,而且使得组播数据总是能够以“接近最优”的路径进行转发。     

网络视频传输中基于IP组播技术的数据库响应速度研究

IP组播是一项旨在节省带宽的技术，通过向数千个用户同步传送一个单独的数据流降低网络流量。组播数据包在网上的某个节点被路由器进行复制，然后根据组播协议进行发送路径的选择。本文分析了网络视频传输过程中远程数据库的响应时间问题，提出了有效的解决方案，从而这种时间上的延迟可以及时的进行实时调整。     

QOS技术在IP城域网上应用

随着数据业务的不断发展繁荣,IP承载网来承载传统语音业务、视频业务、VPN专线业务、组播业务等高附加值业务。由于传统的互联网是基于IP的不面向连接的网络,这种尽力而为的网络,不能根据不同的业务类型提供不同的服务保证,不能保证NGN语音等特殊业务的需求。对于IP承载网而言,在承载多业务大规模的商用运营网的基础上运用QOS实现网络资源的可知、可控、可管成为必然趋势。     

多节点下Ad Hoc网络路由协议模拟

在windows环境下,主要介绍基于NS-2网络模拟器的Ad Hoc网络路由协议的模拟实现。首先对协议模拟软件NS-2进行介绍,接着对现有的Ad Hoc网络的路由协议进行说明,最后对NS-2的方法及工作流程进行解释,并在此基础上针对不同网络模式、不同移动场景和不同的传输负载对表驱动路由协议,按需驱动路由协议进行模拟。结果表明对实时性要求较高的场合适宜使用表驱动协议,而对数据质量和网络带宽有严格要求的场合应使用按需驱动路由协议。     

IP组播路由协议的研究与实现

概述了组播路由协议，分析了协议独立的组播路由－稀疏模式（PIM－SM）的缺陷，提出多个会聚点（RPs)的PIM－SM的改进机制，多个RPs机制有效地提高了原有单个RP的PIM－SM协议的健壮性，有利于实现负载均衡、分类业务及提高系统的容错性能，并讨论多个RPs机制的开销问题。分析了PIM－SM实现细节和组播技术的前景。     

AODV协议在无线传感器网络中的应用

通过对无线传感器网络（Wireless Sensor Network,WSN）和AODV路由协议的特性进行分析,认为AODV协议（Ad—hoc On—Demand Distance Vector Routing）具有在无线传感器网络中应用的可行性,只是在网络能量效率方面考虑不多．本文详细给出了改进方案,利用协议头中原有的保留选项来存储平均路径能量,选路时采用最小路由最大路径能量策略,同时增加转发RREQ和发送RREP的延迟时间．用NS-2软件对改进后方案从吞吐量、延时、剩余能量等角度进行仿真,结果证明该方案可行．     

Bandwidth-Efficient Geographic Multicast Routing Protocol for Wireless Sensor Networks

We present geographic multicast routing (GMR), a new multicast routing protocol for wireless sensor networks. It is a fully localized algorithm that efficiently delivers multicast data messages to multiple destinations. It does not require any type of flooding throughout the network. Each node propagating a multicast data message needs to select a subset of its neighbors as relay nodes towards destinations. GMR optimizes the cost over progress ratio where the cost is equal to the number of neighbors selected for relaying and the progress is the overall reduction of the remaining distances to destinations. Such neighbor selection achieves a good tradeoff between the bandwidth of the multicast tree and the effectiveness of the data distribution. Our cost-aware neighbor selection is based on a greedy set merging scheme achieving a O(Dnmin(D,n)³) computation time, where n is the number of neighbors of current node and D is the number of destinations. As in traditional geographic routing algorithms, delivery to all destinations is guaranteed by applying face routing when necessary. Our simulation results show that GMR outperforms position based multicast in terms of cost of the trees and computation time over a variety of networking scenarios     

Energy Efficient Ambience Awake Routing with OpenFlow Approach

A major problem in networking has always been energy consumption. Battery life is one parameter which could help improve Energy Efficiency. Existing research on wireless networking stresses on reducing signaling messages or time required for data transfer for addressing energy consumption issues. Routing or Forwarding packets in a network between the network elements like routers, switches, wireless access points, etc., is complex in conventional networks. With the advent of Software Defined Networking (SDN) for 5G network architectures, the distributed networking has embarked onto centralized networking, wherein the SDN Controller is responsible for decision making. The controller pushes its decision onto the network elements with the help of a control plane protocol termed OpenFlow. Decentralized networks have been largely in use because of their ease in physical and logically setting the administrative hierarchies. The centralized controller deals with the policy funding and the protocols used for routing procedures are designated by the decentralized controller. Ambience Awake is a location centered routing protocol deployed in the 5G network architecture with OpenFlow model. The Ambience Awake mechanism relies on the power consumption of the network elements during the packet transmission for unicast and multicast scenarios. The signalling load and the routing overhead witnessed an improvement of 30% during the routing procedure. The proposed routing mechanism run on the top of the decentralized SDN controller proves to be 19.59% more efficient than the existing routing solutions.     

A comparative QoS survey of mobile ad hoc network routing protocols

A mobile ad hoc network (MANET) is a wireless, dynamic, infrastructure-less, self-organized, multi-hop, and decentralized network. Each node in MANET can act as a router as well as a work station. Many routing protocols have been developed to increase the efficiency of MANET. The primary objective of this paper is a detailed QoS comparison of reactive (AODV), proactive (DSDV), and hybrid (ZRP) routing protocols of MANET in order to find which routing protocol works best in a particular network scenario. The analysis was made for TCP-based traffic patterns. The performance differentials were analyzed on the basis of normalized routing overhead, packet loss, packet delivery ratio, control packets, end-to-end delay, packet received, and packet sent with a variation of nodes density and mobility. The results were obtained using the NS-2 simulator.     

应用层组播路由的一种改进神经网络解法

研究了使用双层递归神经网络(DRNN)模型求解应用层组播路由的问题.对原有模型的神经元矩阵及能量函数进行改变,并引入了新的线性编程神经元,解决了原模型不能求解组播路由的缺陷.与启发式组播路由算法相比,该解决方案的计算复杂度低,速度较快,而且与其它的神经网络相比,由于引入了基尔霍夫限制条件,保障了解的质量,且所使用的神经元数量少,而在解的精确度上则与其它算法相当.     

Design and implementation of an offload engine for internet group messaging protocol multicast snooping

As internet protocol (IP) networks in the enterprise space continue to mature, with regards to stability and availability, the desire for these networks to deliver multimedia content will grow. Although IP networks have long had enough bandwidth to support multimedia streams, the deployment of this content seems to have been somewhat limited in the enterprise. The control mechanisms for multicast traffic, both at the IP layer and the data link layer, are still the areas that have not been adopted as widely as their more common unicast counterparts. The authors examine the internet group messaging protocol (IGMP) snooping process that currently runs on enterprise switches and propose an offload hardware engine to accelerate it. Currently, many enterprise switches handle this task with a general-purpose processor within the switch. Although this process adds very little to the overall load of systems currently, as multicast transmissions become more commonplace, the need for this process to be offloaded onto specialised hardware will be a necessity, in order to maintain the stability of the switch and the surrounding network. The proposed hardware model simulations reveal significant increase in the number of packets per second that can be handled compared to software implementations.     

QoS Aware Multicast Routing Protocol for Video Transmission in Smart Cities

In recent years, Software Defined Networking (SDN) has become an important candidate for communication infrastructure in smart cities. It produces a drastic increase in the need for delivery of video services that are of high resolution, multiview, and large-scale in nature. However, this entity gets easily influenced by heterogeneous behaviour of the user's wireless link features that might reduce the quality of video stream for few or all clients. The development of SDN allows the emergence of new possibilities for complicated controlling of video conferences. Besides, multicast routing protocol with multiple constraints in terms of Quality of Service (QoS) is a Nondeterministic Polynomial time (NP) hard problem which can be solved only with the help of metaheuristic optimization algorithms. With this motivation, the current research paper presents a new Improved Black Widow Optimization with Levy Distribution model (IBWO-LD)-based multicast routing protocol for smart cities. The presented IBWO-LD model aims at minimizing the energy consumption and bandwidth utilization while at the same time accomplish improved quality of video streams that the clients receive. Besides, a priority-based scheduling and classifier model is designed to allocate multicast request based on the type of applications and deadline constraints. A detailed experimental analysis was carried out to ensure the outcomes improved under different aspects. The results from comprehensive comparative analysis highlighted the superiority of the proposed IBWO-LD model over other compared methods.