In a multi-tiered application, the functionality of the application is separated into isolated functional areas, called tiers

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In a multi-tiered application, the functionality of the application is separated into isolated functional areas, called tiers

We work through the 1st paragraph on Tiered Applications, at quite a high level of abstraction. A more specific «wrapper» Component is also shown, and provides a navigation point, without yet resolving the analysis of its source text; it is hyperlinked to its own dedicated focus diagram.