基于IP网络中IP多播的分析与实现

阐述了IP多播技术，分析了多播传输所必要的多播协议和体系结构等技术特征，讨论了IP多播的运行机制，研究了运用交换机实现多播的技术，概述了使用阿尔卡特三层交换机在网络中实现IP多播的过程．     

基于IP多播的数字视频监控系统网络体系

提出并实现了一种基于IP多播的数字视频监控系统的网络系统.介绍了系统的网络设计要求,说明了该系统的设计思想-基于TCP/IP协议、客户-服务器模型、IP多播、WinSock2方式与流媒体通信相结合,实现实时图像传输和远程控制.     

基于IP多播的数字视频监控系统网络体系

提出并实现了一种基于IP多播的数字视频监控系统的网络系统.介绍了系统的网络设计要求,说明了该系统的设计思想-基于TCP/IP协议、客户-服务器模型、IP多播、WinSock2方式与流媒体通信相结合,实现实时图像传输和远程控制.     

可靠多播协议的分类研究

对于大规模多媒体多播应用来说，一个有效发现和修正传输错误的可靠多播协议是必要的，它吸引了许多爱好者。由于不同多播应用对可靠性的要求各不相同，因此很难找到一种可靠多播协议能满足所有可靠性需求．从用户需求、体系结构、机制、重传模式和策略等方面对典型的可靠多播协议进行研究，讨论了可靠多播协议的分类、适用范围和将来的研究方向．     

基于RTP/RTCP的音视频WiFi传输系统的设计

本系统设计了一个无线WiFi音视频传输方案,可用于视频监控,视频教学,旅游导游等领域.系统采用i.MX27多媒体处理器,WiFi模块采用基于IEEE802.11b的无线协议,流媒体传输采用RTP/RTCP协议,视频的编解码采用成熟的MPEG4标准,实现基于2.4GHz无线网络传输的音频流和视频流数据的传输.实现了音视频的WiFi传输,在接收端音视频还原流畅.     

自组网中基于能量约束的QoS多播路由优化算法

在分析基于能量优化多播路由算法的基础上,提出了一种QoS多播路由的网络模型,并在网络模型的基础上,结合能量模型、极值元素组合和改进的遗传算法提出了一种基于能量的QoS多播路由优化算法EQMROA.仿真结果表明此算法是可行和有效的.它为移动Ad Hoc 网络QoS多播路由技术提供了一种新的有效途径.     

交通监控中基于压缩感知的WMSN视频编解码

在交通监控中,利用WMSN节点获取路况视频,适用于复杂多变的地理环境,但视频图像数据量大,而WMSN节点资源受限。基于压缩感知技术和传统视频编码理论,提出了一种新的WMSN视频编解码方法。在编码端,依据视频图像的相关性对视频流进行分帧,再根据其特点分别进行压缩感知处理。在解码端,运用OMP算法重构关键帧和残差帧视频图像,进而恢复视频流。仿真实验表明,在保证视频图像重构质量的前提下,可以减少监控网中视频传输的数据量。     

移动Ad Hoc多播路由协议研究

如何在移动自组网中实现有效的多播路由技术是当前此领域研究中亟待解决的间题．文中对当前一些典型的多播路由协议进行了研究，从多播路由的拓扑结构、发现策略以及对单播路由的依赖等方面对它们进行了分析比较，并对多播路由的进一步研究方向进行了展望．     

一种移动Ad Hoc网络多播路由协议

提出了一种基于分割树的移动Ad Hoc网络（MANET）多播路由协议（TPBOM）.该协议中,信源基于成员节点的定位信息创建一个Steiner树覆盖图.为满足可扩展多播群的要求,信源再利用最大权反向分割（MHRTP）的树分割算法将其分割为若干个区,并将每个区封装进一个树分发数据包中,以便将所创建的Steiner树分发至所有成员节点.封装的数据包中不包含目的地址列表,数据则沿该Steiner树进行传输.仿真结果表明,TPBOM在可扩展的多播群中获得了较高的性能.     

P2P系统发现技术的研究与实现

现今的互联网发展中，对等（P2P）网络以其开放的非中心化特点带来的优势越来越受到人们的关注，然而由于这种开放式网络固有的强动态性，经常需要进行信息交互的对策点很难实现彼此定位，如何解决对等点间发现问题显得至关重要，文中提出了一个结合多播和超级对等点（SP）概念的适用性较广的发现模型，并讨论了其实现方法。     

IP组播技术在视频监控系统中的应用

对IP组播技术和其在视频监控系统中的应用作了介绍,采用IP组播技术实现监控视频的多点传输,可以大大节省网络带宽资源,提高数据传送的效率。     

File Transfer Algorithm for Autonomous Decentralized System

A file transfer algorithm based on ADP (autonomous decentralized protocol) was proposed to solve the problem that the ADS (autonomous decentralized system) middleware (NeXUS/Dlink) lacks of file transfer functions for Windows. The algorithm realizes the peer-to-peer file transfer, one-to-N inquiry/multi-response file transfer and one-to-N file distribution in the same data field based on communication patterns provided by the ADP. The peer-to-peer file transfer is implemented through a peer-to-peer communication path, one-to-N inquiry/multi-response file transfer and one-to-N file distribution are implemented through multicast commtmieation. In this algorithm, a file to be transferred is named with a GUID ( global unique identification), every data packet is marked with a sequence number, and file-receiving in parallel is implemented by caching DPOs (data processing objects) and multithread technologies. The algorithm is applied in a simulation system of the decentralized control platform, and the test results and long time stable mrming prove the feasibility of the algorithm.     

基于层次结构的应用层多播方案

研究了P2P网络的应用层组播中共享树建立的机制,提出了一种基于层次结构的应用层组播方案.该模型从逻辑上分上下两层,上层由信息节点组成的可靠分布树型覆盖网络,下层由具有各种资源的网络节点组成,采用层次结构的协议具有很好的扩展性,可以连接IP多播岛来充分利用IP多播的高效率,可以根据特定的域灵活选择相应的应用层多播协议.该模型具有较低的控制开销、较高的带宽利用率和较高的数据传输率,较好的提高多播性能.     

基于定长帧的组播QoS路由技术

为高效利用网络资源且平衡负载,结合物理帧时槽交换技术,提出了基于定长帧的组播机制和QoS路由算法MRBP.该算法在满足带宽和时延要求的基础上,最小化时延和平衡节点负载,达到组播树总体时延较小并优化利用网络资源的目的.仿真结果表明,基于该算法建立的组播树具有较好的网络负载平衡性,并能够对服务质量提供较好的保证.     

基于蚁群算法的多QoS约束的多播路由优化算法

蚁群算法是一种新型的随机优化算法,能有效地解决QoS受限的多播路由问题.文中基于蚂蚁具有找到蚁巢与食物之间的最短路径的工作原理,并在分析多约束QoS的多播路由的基础上,提出了一种具有全局优化能力的多播路由算法(OQMRA),仿真实验表明了该算法是合理的和有效的.     

THE DLSTRIBOTED MCU MODEL FOR SYNCHRONOUS REAL-TIMETELETEACHING

Aiming at issues on multimedia communication in synchronous real-time teleteaching (SRT) systems over IP network, a 4-tuple structural mode of multimedia communication is proposed in the paper, and an SRT-oriented distributed MCU model is built according to the mode. Moreover, the mechanism of multicast communication across subnets is discussed. The distributed MCU model has been applied successfully in our interactive synchronous real-time telesteaching system RealClass and has shown good extendibility in operation.     

A Reliable Adaptive High-Definition Transmission System for Distance Learning

There is an increasing demand for supporting high-quality real-time audiovisual services for the next generation wired and wireless networks. However, due to variety of bandwidths of different networks, it is a great challenge for deployment. In this paper, a novel high-definition (HD) video transmission system was proposed which depends upon reliable compound multicast protocols and QoS control over the various kinds of networks. This system detects client's network condition and assigns it to a proper proxy. Each proxy is capable of detecting network parameters and adaptively tuning such transport parameters as bit rate, video resolution, frame rate and QoS mechanisms to this condition. It also provides FEC error recovery under consideration of characteristics of MPEG4 video codec. Our simulation demonstrates that different network clients such as ADSL, CERNET, and CERNET2 can receive more video reliability with less delay.     

Topology-aware overlay multicast over IP multicast networks

Most existing overlay multicast approaches refuse to consider any network layer support no matter whether it is available or not. This design principle greatly increases the complexity of the routing algorithms and makes the overlay topologies incompatible with the underlying network. To address these issues, topologyaware overlay multicast over IP multicast networks （TOMIMN） was proposed as a novel overlay multicast protocol, which exploits the cooperation between end-hosts and IP multicast routers to construct a topologyaware overlay tree. Through a little modification to protocol independent multicast sparse mode （PIM-SM）, a multicast router is able to receive registration from nearby group members and redirect passing-by join requests to them. Due to the multicast router＇s support, TOMIMN organizes its group members into an overlay multicast tree efficiently, which matches the physical network topology well.