IMS中基于策略QoS管理模型

摘要

IMS(IP Multimedia Subsystem) gives customers a rich multimedia experience. At the same time, it proposes a heigher demond about QoS(Quality of Service) management. Network operators will need to formulate different policy through service differentiation. Although 3GPP have defined Policy-based QoS management architectures, these architectures are only logical architectures and not physical implementations. This paper analyzes Policy-based QoS management model, proposes a implementation scheme which refers to 3GPP standards, designs and realizes Policy Decision Function and Pocicy enforcement Function which are key servers in the model. Upon testing, this service model can correctly complete the subscriptions of policy information, policy decision, bandwidth requirement, QoS class consultations and provide reference to Network operators.%IMS(IP多媒体子系统)给客户带来丰富的多媒体体验的同时,也对服务质量(QoS)管理提出了更高的要求,即针对不同用户定制的不同服务,网络运营商应该制定差异化的策略进行QoS管理.3GPP定义了基于策略的(oS管理框架,但这个框架只是逻辑上的架构,没有定义具体物理实施的方案.对基于策略QoS管理模型进行了分析,在参照3GPP定义的标准基础上,提出了一种管理模型的实现方案,设计并实现了该模型中两个关键服务器策略决策服务器(PDF)和策略执行服务器(PEP).经过测试,两个服务器能互相配合,正确完成查询策略信息,做出策略决策,执行带宽请求预留、QoS等级协商功能,为网络运营商提供了参考.