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2..The Road to SDN 单词学习

翻译

Making computer networks more programmable enables innovation in network management and lowers the barrier to deploying new services. In this section, we review early work on programmable networks. We divide the history into three stages, as shown in Figure 1. Each stage has its own contributions to the history: (1) active networks (from the mid-1990s to the early 2000s), which introduced programmable functions in the network to enable greater to innovation; (2) control and data plane separation (from around 2001 to 2007), which developed open interfaces between the control and data planes; and (3) the OpenFlow API and network operating systems(from 2007 to around 2010), which represented the first instance of widespread adoption of an open interface and developed ways to make control-data plane separation scalable and practical

使计算机网络更具可编程性有助于网络打点的创新，并降低部署新处事的障碍。在本节中，我们将回顾可编程网络的早期事情，将历史分为三个阶段。每个阶段对历史都有本身的孝敬。

主动网络（从20世纪90年代中期到21世纪初），它在网络中引入了可编程成果，以实现更大的创新。

控制和数据平面疏散（从2001年到2007年摆布），开发了控制和数据平面之间的开放接口。

OpenFlow API和网络操纵系统（2007年至2010年摆布），代表了广泛给与开放接口的第一个实例，并开发了使控制数据平面疏散具有可扩展性和实用性的要领

Network virtualization played an important role throughout the historical evolution of SDN, substantially predating SDN yet taking root as one of the first significant use cases for SDN. We discuss network virtualization and its relationship to SDN in Section 3.

网络虚拟化在SDN的历史演进过程中饰演着重要的角色，它在SDN呈现之前就已经有了本色性的成长，但作为SDN最早的重要用例之一，网络虚拟化已经扎根于SDN之上。我们在第3节讨论了网络虚拟化及其与SDN的关系。

2.1 Active Networking 单词学习

翻译

The early- to mid-1990s saw the Internet take off, with applications and appeal that far outpaced the early applications of file transfer and email for scientists. More diverse applications and greater use by the general public drew researchers who were eager to test and deploy new ideas for improving network services. To do so, researchers designed and tested new network protocols in small lab settings and simulated behavior on larger networks. Then, if motivation and funding persisted, they took ideas to the Internet Engineering Task Force (IETF) to standardize these protocols. The standardization process was slow and ultimately frustrated many researchers

20世纪90年代初到中期，互联网蓬勃成长，其应用及吸引力远远赶过了早期的文件传输和科学家电子邮件应用措施，更多样化的应用措施和更广泛的公家使用，吸引了巴望测试和部署改造网络处事的新想法的研究人员。为此，研究人员在小型尝试室环境中设计并测试新的网络协议，并在大型网络上模拟行为，如果动机和资金连续存在，他们会将想法提交给互联网工程出格事情组（IETF）以使这些协议标准化。标准化过程迟缓，最终使许多研究人员感想沮丧。

In response, some networking researchers pursued an alternative approach of opening up network control, roughly based on the analogy of the relative ease of re-programming a standalone PC. Specifically, conventional networks are not “programmable” in any meaningful sense of the word. Active networking represented a radical approach to network control by envisioning a programming interface (or network API) that exposed resources (e.g., processing, storage, and packet queues) on individual network nodes, and supported the construction of custom functionality to apply to a subset of packets passing through the node. This approach was anathema to many in the Internet community who advocated that simplicity in the network core was critical to Internet success.

于是，一些网络研究人员给与了一种开放网络控制的替代要领，大抵是基于对独立PC从头编程相对容易的类比。具体地说，传统网络在任何意义上都不是“可编程”的，主动网络代表了一种激进的网络控制要领，通过设想一个编程接口（或网络api）来果然各个网络节点上的资源（例如，措置惩罚惩罚、存储和数据包行列队伍），并撑持构建应用于子集的定制成果。这种要领遭到许多互联网社区人士的憎恨，他们主张网络核心的简单性对互联网的告成至关重要。