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.     

Performance comparison of multicast routing protocols based on NS-2

The electronic system in a comprehensive shipboard has a extremely wide bandwidth. It supports synchronized and asynchronous data transmission, multimedia correspondence, and videophone conferencing. In order to guarantee the security and correspondent real time of the communication, choosing a multicast routing protocol based on different applications is a key problem in terms of the complexity of the system. A simulation model was first designed for existing multicast routing protocols in NS-2 and analysis was performed on their corresponding application environments. The experiments proved that PIM-DM based on the shortest-path tree protocol is suitable for communication in the field of comprehensive shipboard. Further work that is necessary is also discussed.     

铁路高清视频监控方案探讨

为了更好的在事故发生时进行事件追溯,高清化是铁路综合视频监控系统必然的发展趋势,而高清视频监控系统将对目前的铁路综合视频监控系统在网络、存储、服务器处理能力等各方面带来一系列问题。采用视频流组播方式及视频分析技术,得出一个初步的解决方案。     

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。     

多QoS约束的动态多播路由算法

对具有延迟、带宽和低代价等多OoS约束的多播路由算法进行研讨，描述了一种适应于研究OoS多播路由的网络模型，提出一种具有多OoS约束的动态多播路由算法（DMRAQoS），DMRAQoS试图有效地减少生成多OoS约束的多播树的开销，使多播组成员能动态地加入／退出多播会晤，且不干扰现有的多播树。仿真实验结果表明，与YAM和QoSMIC比较，DMRAOoS具有较小的延时和较少的代价。     

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.     

IP MULTICAST GROUP MANAGEMENT FOR BROADCAST LANS DISTRIBUTION

IntroductionThere are two traditional types of communica-tion in computer networks:unicastand broadcast.A unicast address (one to one) is designed to sendmessages to a single destination in a network.Abroadcast (one to all) address is used to send datato the entire network(all hosts) .Multicast(oneor many to many) can be viewed either as an inter-mediate case,or as a generalized mode encompass-ing both unicast and broadcast as special cases.Inmulticast mode,messages are sent to an arbitraryse…     

求解QoS组播路由问题的改进蚂蚁算法

蚂蚁算法是一种相对较新的启发式方法,通过模拟蚂蚁的觅食行为,提出了求解Qos组播路由问题的改进蚂蚁算法。仿真实验表明,该算法能以较高速度收敛,有效地解决QoS组播路由问题。     

基于移动IPv6的组播技术研究

介绍了一种移动节点（Mobile Nodes简称MNs）动态加入和离开组播组（Mukicast Group简称MG）的结构，该结构是基于hash算法提出的。同时阐述了移动IPv6（Mobile IPv6简称MIPv6）网络中由MNs构成的动态传递树的构造过程。这种动态传递树的树枝表示数据包从源地址到目的地址的最短路经。必要的时候，这些树枝可以增加或删除。每个MNs都分配了一个组播地址，通讯对端（Correspondent Nodes简称CNs）发送数据包到MG。当MNs移动到一个新位置时，该MNs在新位置上必须加入MG才能接收数据包。通过建立模型可以检测一下这种新结构的功能。仿真结果显示了MNs加入和离开MG的动态性直接影响了切换时间和转换的平滑性。     

无线传感网络中QoS约束多播路由算法

分析了无线传感网络中具有时延、带宽和剩余能量等多QoS约束的多播路由问题.描述了一种适应于研究QoS多播路由的网络模型.提出了一种具有多QoS约束的能量有效的多播路由算法(EMRA),该算法成功地解决了无线传感网络中多播节点动态变化时的QoS路由选择问题.仿真实验证明了EMRA的有效性和优越性.