基于ATCA流媒体网络服务器研究

【作者】 胡金洪；

【导师】 孔繁胜；

【作者基本信息】 浙江大学 ， 计算机应用， 2006， 硕士

【摘要】 流媒体系统随着Internet的发展而不断壮大,对于底层的计算平台也提出了更高的要求——更为强大的计算性能、更为强大的数据传输能力、与强大计算性能相配套的散热性能和更为强大的系统管理能力,现存的计算架构难以应对。而先进电信计算架构(Advanced Telecom Computing Architecture,ATCA)在计算性能、网络传输能力、管理性能以及专属特性设计方面和原有的计算架构相比都有着明显的优势。ATCA是由PICMG组织(PCI Industrial Computer Manufacturers Group)提出的PICMG3.X一系列规范总称,是高性能的电信和工业计算应用开发开放的标准,非常适合构建流媒体系统。 本文阐述了基于ATCA的流媒体系统架构,分析了系统组成,并且设计了各个模块的功能.系统具有高度可伸缩性,统一的管理平台,灵活的内容分发子系统,广泛的硬件、应用和内容支持,丰富的接口等特点。 在流媒体系统中网络服务器设计是关键之一。在网络服务器设计过程中,本文总结了一些关键设计问题,如数据拷贝、上下文转换、内存分配、锁竞争等,同时提出了针对上述问题所要遵循的原则。 在网络服务器模型中,有线程驱动模型和事情驱动模型。虽然线程是表示并发的主要方式,但是在线程驱动模型服务器中,随着线程数目不断增加,系统的开销不断增长,到一定程度后会导致系统总体性能的下降;而事件驱动模型网络服务器用一个线程处理所有任务,避免了同步引起的很多问题,但是事件驱动模型不能利用SMP来提高性能,并且事件处理线程有可能阻塞。 基于线程驱动模型和事件驱动模型的特点,本文提出了网络服务器设计框架混合模型,充分利用了两种模型的优点。最后归纳了如何运用Wrap、Pipeline、Replicate、Combine等设计模式构建基于混合模型的流媒体网络服务器。最后阐述了CDN系统的结构以及其中的关键技术。更多还原

【Abstract】 With the rapid development of Internet, streaming media system expands it’s use continuously, so it requires the rock-bottom computing platform higher performance—more powerful computing performance 、 more high speed data transmission、 more formidable heat dissipation ability and more strong system management ability. The extant computing platform cannot meet these requirements. But ATCA (Advanced Telecom Computing Architecture) has the obvious superiority in all of computing performance, the ability of network transmission, management performance as well as the private characteristic design aspect etc. ATCA is a series of standards PICMG3.X proposed by PICMG (PCI Industrial Computer Manufacturers Group) ,is open standard for high performance telecommunication and industry system development, so it is very suitable using in steaming media server system.This paper elaborates streaming media system architecture based on ATCA, analyzes the system composition, and defines each module function. The system is highly expandable. Also, it has uniform management platform, flexible content distribution system, widespread support of hardware, application and content, rich interface and so on.Network server design is one of the most important key in implementing a streaming media system. In design the network server, some essential questions are summarized, like data copy, context switches, the memory Allocation, lock contention and so on simultaneously proposes some principles in view of above questions.Threaded server and event-driver server is the two most general network servers. Threads have become the dominant form of expressing concurrency, but in threaded server, as the number of threads in a system grows, operatingsystem overhead increases, leading to a decrease in the overall performance of the system. Event-driven systems are typically structured as a program thread that loops continuously, processing events of different types from a queue. Event-driven programming avoids many of the bugs associated with synchronization. However, Events generally cannot take advantage of SMP systems for performance. Also, event processing threads can block regardless of the I/O mechanisms used.According to Threaded Servers and Event-drive Servers’ characteristics, a hybrid thread and event server is proposed to obtain both benefit of threads and events. The paper also induces how to use design rules such as Wrap, Pipeline, Combine and Replicate to design streaming media network server. At last, it describes the CDN system architecture and looks into the key technologies.更多还原