Request Routing for Scalable Services

群集技术使因特网服务器站点能够以适度的成本逐步扩展。 在基于集群的服务架构中，使用集成到网络交换结构中或插入在客户端和服务器之间的重定向中介来在服务器之间分配传入请求流量越来越常见。 然而，互联网服务及其交付架构继续快速发展。 这为重定向中介带来了新的挑战和机遇，并激发了对请求重定向机制和特定服务环境的请求路由策略的基础研究，这项工作将开展一项协调的研究计划，以扩大重定向中介作为可扩展Internet服务的使能技术的潜力。 这项工作主要集中在集成服务感知重定向和请求路由作为网络级功能的高速交换架构。 该方法结合了模拟、软件原型的构建以及使用合成和真实的工作负载对原型进行评估。 更好地理解请求路由作为大规模互联网服务的推动者的作用， 在大型系统中评估这些策略的仿真结果， 软件原型，展示这些解决方案在基于Web的服务和网络存储服务的实践中的价值，以及 有机会培养学生作为参与者在研究生和本科生水平的这项研究。综上所述，本文的研究工作有以下几个基本目标：1. 在传输协议级别定义重定向所必需的协议功能。 交换机根据特定于服务的路由策略将每个传输连接上的传入请求路由到任何活动服务器;称为任意点通信。2. 实现支持任意点的传输协议，支持服务协议通常需要的功能：可靠通信、排序和重复抑制以及拥塞控制。3. 定义Anypoint中介中特定于服务的策略模块的接口和功能。 这定义了一个架构，用于将服务协议实现分解为客户端、服务器和服务模块，以扩展中间层。 通过构建虚拟化服务实现的软件原型来评估Anypoint定义的中介架构。 最初的目标是HTTP 1.1应用程序服务和NFS。

Clustering technologies enable incremental scaling of Internet server sites at modest cost. It is increasingly common in cluster-based service architectures to distribute incoming request traffic among servers using redirecting intermediaries integrated into the network switching fabric or interposed between the client and servers. However, Internet services and their delivery architectures continue to evolve rapidly. This creates new challenges and opportunities for redirecting intermediaries, and motivates basic research in both the mechanisms for request redirection and the request routing policies for specific service environments.This work will undertake a coordinated research program to expand the potential of redirecting intermediaries as an enabling technology for scalable Internet services. The work focuses primarily on integrating service-aware redirection and request routing as network-level functions in a high-speed switching architecture. The methodology combines simulation, construction of software prototypes, and evaluation of prototypes using synthetic and real workloads.The expected outcomes of the work are: An improved understanding of the role of request routing as an enabler for large-scale Internet services, Simulation results evaluating these policies in large systems, Software prototypes that demonstrate the value of these solutions in practice for Web-based services and network storage services, and Opportunities to train students as participants in this research at both the graduate and undergraduate levels. In summary, the research work has the following basic objectives:1. Define protocol features essential for redirection at the level of the transport protocol. The switch routes incoming requests on each transport connection to any active server at the discretion of a service-specific routing policy; referred to as Anypoint communication.2. Implement an Anypoint-capable transport protocol that supports features commonly required by service protocols: reliable communication, ordering and duplicate suppression, and congestion control.3. Define interfaces and capabilities for service-specific policy modules in Anypoint intermediaries. This defines an architecture for decomposing service protocol implementations into a client, a server, and service module to extend the intermediary.4. Evaluate the intermediary architecture defined by Anypoint by constructing software prototypes of virtualized service implementations. The initial targets are HTTP 1.1 application services and NFS.