Study on Intelligent Router for Multimedia Network

在本研究中，为了建立实现未来高速增强型多媒体网络的必要技术，重点研究了以下两项技术，并对其进行了详细的实际研究；多媒体路由器的构建技术基于层次链接共享的按需检索和信息传递技术。关于这个问题，我认为……为了实现MPLS流量工程，提出了一种基于内容可寻址存储器（CAM）的MPLS标签快速查找机制。利用现有的CAM速度进行定量评估，我们提出的机制可以达到10Gbps的处理速度。其次，提出了分层缓冲区管理方案，该方案考虑到输出端口、优先级类和流的层次结构，公平地共享缓冲区空间和到输出链路的传输速度。在此基础上，利用硬件级规范语言部分设计了所提出的缓冲区管理方案。至于问题2。提出了适用于未来宽带网络的分组传输型视频点播方案Burst-VOD，并通过软件实现了主要部分和基础部分。在IP网络中验证了原型系统的正常行为。其次，为了提高一般MPEG视频传输的QoS，我们提出了端到端的控制，如根据帧属性（即I、P、B帧）进行优先级类传输、基于帧的丢弃和基于gop的变换，以及基于类的RED（随机早期检测）、基于类的缓冲调度RR（轮询）和加权RR（WRR）等路由器内部控制的协同组合。然后，通过计算机仿真对这些组合方法进行了评价。结果表明，尽管WRR需要相当复杂的权值估计机制，但它是非常有效的；RED对属于最低优先级的b帧类的控制更为有效，等等。

In this study, in order to establish the essential technology to realize the highly enhanced high-speed multimedia network in the future, the following two techniques are focused on and actually studied in detail ;1. Construction technology of the multimedia router.2. On-demand retrieval and information delivery techniques using hierarchical link sharing.As for the issue 1., fast MPLS label look-up mechanism using CAM(Content Addressable Memory) has been proposed to implement the MPLS traffic engineering. As a result of the quantitative evaluation by using the existing CAM speed, Our proposed mechanism can be attained to 10Gbps processing speed. Next, hierarchical buffer management scheme has been proposed, where buffer space and transmissionspeed to the output links are shared fairly taking into account the hierarchy of output ports, priority class, and flows. Furthermore, proposed buffer management scheme was designed by hardware level specification language partly.As for the issue 2., Block transfer type VOD scheme called Burst-VOD suitable for the future broadband network has been proposed, and main and fundamental parts were implemented by software. Proper behavior of the prototype system was confirmed in the IP network. Next, as way to enhance the QoS for general MPEG video transfer, we presented the cooperative combination of the End-to-End control such as priority class transfer according to the frame attributes, i.e. I, P, B frames, frame-base dropping and GOP-base shuffling, and the intra-router control such as class-base RED(Random Early Detection), class-base buffer scheduling RR(Round Robin) and Weighted RR(WRR). Then, these combinational methods are evaluated by computer simulation. As results, in particular, it is confirmed that WRR is very effective though it requires quite complicated weight estimation mechanism, and RED control to the B-frame class which belongs to lowest priority class is more effective, and so on.