We'll refer to the first two layers as high-level and low-level service layers.

我们将前两层称为高级服务层和低级服务层。

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A service is an application that runs at a low level and without a display or UI.

服务是在较低级别运行的一个应用程序，没有显示，也没有UI。

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For example, no business-level process or service view can be obtained if the primary concern is how low-level building blocks, representing technical devices, interconnect at a macro-level.

例如，如果主要的问题是表示技术设备的低级构块如何在宏观层次互连，则无法获得业务层流程或服务视图。

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This structure has resulted in tremendous low-level innovation and optimization as each team strives to outperform its targets and its internal and external service-level agreements (SLAs).

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