移动多媒体信息系统可伸缩性关键技术研究

Mobile devices need to access servers in fixed networks. The heterogeneity in.the communicating devices needs to be handled through different forms of.software-supported adaptation, delivering data in formats suitable for the devices..The adaptation can be implements via server-based, proxy-based, and.client-based models. High capabilities of calculation and storage are required to.execute the adaptation, resulting in low system capacity and service quality..We analyze the access behavior and traffic characteristics of typical mobile.services, study and compare the performance of different adaptation approaches.We find that for a typical unified web site, 10% of access requests are from mobile users, 90% from PC users. The processing load of server or proxy.working in adaptation mode may increase by about 10 times or more. In order to.provide differential services and increase the scalability, the server-adaptation.and proxy-adaptation should coexist. They are suitable for paid and free services.respectively. Paid services account for about 80% of mobile traffic, and free.4services account for 20%. Thus traffic and processing load is divided rationally..The coordination between server-adaptation and proxy-adaptation can be.achieved via CC/PP embedded in HTTP header. We also give several new or.improved techniques, such as XML pretranslation, object variants cache.management, long file truncation. The the processing efficiency of the adaptation.system can be increased by 2-10 times.

为提供大量个性化服务，移动多媒体信息系统须有很好的可伸缩性。需要将代理网关从信息转换中解脱出来，以管理和控制功能为主，综合实现全IP移动网络、WWW、WAP1.2中都具有挠没芰ζ谩⑼萍际酢Ｔ捶衿魈峁┬畔⒆皇逝涔δ埽擞肵THML等技术提供个性化服务。