Because component tests deal with multiple layers of an architecture, they often deal with databases, file systems, network elements, etc.

由于组件测试处理一个架构的多个层次，所以它们经常用于处理数据库、文件系统、网络元素等。

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A layer of video program (310) that has been encoded into multiple layers is downloaded via the first or second network (210 or 220).

编码到多个层中的视频节目(310)的层通过第一或第二网络(210或220)得到下载。

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With NGFWs, multiple layers of redundant protection are available at the firewall level as well as the network and client device level.

FORBES: Next-Generation Firewalls: What Makes Them Next-Gen

With multiple manufacturers and their own UI layers, over a number of handset variants, all tweaked by each network (who may then add their own applications into the mix), even after the code is changed an upgrade is not a simple process.

FORBES: Android Lags Behind Apple As iOS6 Adoption Shows The Benefit Of A Tight Ecosystem