面向应用适应能力的互联网体系结构评估方法

The Evaluation Method towards the Application Adaptability of Internet Architecture

互联网体系结构的演进已经成为学术界和工业界的共识,面向现有体系结构存在问题的修补策略以及基于各种思路的新的体系结构方案不断被提出,但得到大众认可并得到应用的少之又少.如何评估这些策略和方案是否符合互联网体系结构发展的需求成为当前急需解决的一个重要问题.现有的评估工作大多从用户或者ISP的效益出发对互联网体系结构的竞争力和演化趋势进行评估,它们并不考虑应用类型变化对互联网体系结构发展的影响.文中从应用的角度出发,立足于体系结构本身,提出了一种面向应用适应能力的体系结构评估方法,并构建了相应的评估模型2ACT(Application Adaptation CapaciTy),该方法以体系结构的服务适应性(Service AdapTability)及经济适应性(Economic AdapTability)为基础进行建模,以量化应用数据类型变化、应用部署开销对互联网体系结构发展的影响.该方法不但可用于评估体系结构自身的发展趋势,也可用于对体系结构中各种协议或机制的发展能力进行评估.针对当前多媒体数据流量剧增的现象,文中对两种适于多媒体数据应用的机制(In-network内容缓存机制和IP组播协议)进行了评估,结果发现这两种理论上具有优势的协议需在一定的限制条件下部署才能发挥其优势.用户或ISP可以结合自身的应用需求,根据2ACT模型的评估结果,选择相应的体系结构或者协议进行部署.

The development and innovation of Internet architecture have become the consensus in academia and industry. Many strategies have been proposed to fix various problems of current architecture, and even many new architectures are being considered. However, few of these new strategies or architectures have been accepted and employed in real applications. It is therefore an important and urgent task to construct a model that can be used to evaluate these strategies and architectures in response to the development requirements of Internet architecture. Most existing works used to study the competitiveness and the development trend of candidate architectures are mainly based on the economic framework, only taking into considerations of the costs and benefits to the users and ISP （or providers）, while ignoring the impact of the change in the composition of application data. This paper fills this gap by proposing a method to evaluate the applica tion adaptation capacity of the Internet architecture from the application perspective. A corresponding 2ACT （Application Adaptation CapaciTy） model is also constructed. This method constructs the model based on the service adaptability and economic adaptability of the architecture and quantifies the effects of application data composition and application deployment cost on the development of the architecture. It can be used to evaluate not only the development trend of the architecture but also the development capacity of the protocols and mechanisms within the architecture. In light of the fast growing multimedia data traffic in the Internet, this paper uses the proposed model to evaluate the two multimedia application mechanisms, In-network content caching mechanism and IP multicast protocol. The evaluation results show that these two theoretically sound mechanisms only perform well under certain situations. ISPs and customers can make their own choice based on their own application needs and our findings.