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基于IXP425嵌入式P2P板卡的设计与实现
【作者】 兰品雄；
【导师】 陈泽祥；
【作者基本信息】 电子科技大学 ， 光学工程， 2008， 硕士
【摘要】 多媒体的大量应用推动了流媒体技术的发展,使得流媒体的应用,诸如视频直播、视频点播、远程教学、远程医疗、视频会议等等已经深入人心,为我们的经济生活创造了极大的便利。尽管应用越来越广泛,迫切需要解决的问题也越来越多,在视频直播和视频点播中,一旦大量的客户同时向服务器申请业务时,不仅现今的带宽远远不够,服务器也会面临空前的压力,反应速度变慢,服务器的性能直线下降,而客户端也由于得不到数据而处于漫长的等待之中。本文所构建的硬件系统为解决上述服务器端和客户端的问题提供了平台。本课题以IXP425网络处理器为核心构建了嵌入式P2P板卡,并完成底层软件的定制和移植。本系统具体包括以下几部分:IXP425与其周边的存储模块、网口模块、PCI电平转换及金手指部分模块、JTAG及串口部分模块、电源及复位电路模块。其中FLASH用来装载操作系统和启动代码,SDRAM用作运行程序的空间;网口模块包括两个NPE接口,其中之一用来调试下载程序,另一个用作网络应用接口;PCI电平转换及金手指部分模块则是由于本系统将要作为PCI拓展卡的形式插在普通PC机主板插槽工作,其中涉及PCI通信规范;JTAG及串口部分模块的设计则是为了下载和调试软硬件的方便,在嵌入式系统设计中,这两部分是很成熟的技术;电源部分则是为IXP425内核和内部外围部件提供不同的电压;复位电路部分的设计严格遵守芯片对复位时序的要求。在软件设计方面,本文根据本系统的具体要求,定制和移植了启动代码Redboot和Snapgear Linux操作系统。经过大量的软硬件调试,实践证明本文所构建的嵌入式P2P板卡能稳定运行,为本课题组的软件人员提供了良好的软硬件平台,保证了本项目的顺利进行。本嵌入式P2P板卡具有一定的通用性,加上合适的软件,即可实现路由器、网关等其他一些功能。具有较高的应用价值。
【Abstract】 The wide application of multimedia contributes to the development of streaming media technology, which makes the application of streaming media, such as video-live-broadcast, video-on-demand, long-distance education, telemedicine, video conference, etc., attracted by a large number of people and creates massive benefits to our economic life. In spite of the increasingly wide application, more and more urgent problems remain to be solved. Take the video-on-demand and video-live-broadcast for example, once a great amount of applications for business occur at the same time, the inadequacy of present bandwidth is becoming obvious, and the server will also be put under a tremendous pressure—the response is decelerated, the performance of server decreases abruptly, and the customers will have to wait for a long time before they obtain required data.The hardware system constructed in this paper provides a platform for solving the above problems related to the communication between server and customer. Embedded P2P board was constructed based on a core net processor of IXP425. The design and transplantation of the bottom software were realized. This system includes the following components: IXP425 and the memory modules, NPE modules, PCI voltage level transformation and golden finger modules, JTAG and series port modules, power supply and reset circuit modules. FLASH is used to store operating system and starting code and data. SDRAM provides a space for program operation. NPE modules consist of two NPE interfaces, one of which is used to debug and download programs, and the other is as network application interface. The introduction of PCI voltage level transformation and golden finger modules is due to the need of inserting this system in the form of PCI extended card into the mainboard socket of ordinary PC computer, which is related to PCI communication standard; the design of JTAG and series port modules is for the convenience of downloading and debugging hard and software. The above two technologies are matured in the design of Embedded system. The power supply provides varied voltages to the internal core and external components. The reset circuit is designed to conform strictly to the requirements of chips on reset timing. In the aspect of software design, we fabricated and transplanted start code Redboot and Snapgear Linux operating system according to the specific requirements of this system. Via a large number of debug processes, results demonstrated that the imbedded P2P board constructed in this paper can run steadily, which provides a good platform for the software researchers of the group, and ensures the smooth operation of this program.This P2P Embedded board is generic to a certain extent, and can realize some other advanced functions such as router and gateway. It is of a high value for application.