We posted our patterns & practices Reference Application Architecture Cheat Sheet on CodePlex.  It’s an overview of a layered architecture, including an brief explanation of each layer and the relevant components.

Layered Architecture at a Glance
Here’s a figure that shows the layers and components:

Layers
Here’s a brief summary of the layers:

• Presentation Layer - Presentation layer components implement the functionality required to allow users to interact with the application.
• Business Layer - Business layer components implement the core functionality of the system, and encapsulate the relevant business logic.
• Data Layer - Data layer components provide access to data that is hosted within the boundaries of the system, and data exposed by other back-end systems.
• Services Layer - Services layer components provide other clients and applications with a way to access business logic in the application, and make use of the functionality of the application by passing messages to and from it over a communication channel.

Components
Here’s a listing of the key components for each layer:

Presentation Layer Components

• User Interface (UI) components
• UI process components

Business Layer Components

• Application facade
• Business components
• Business workflows
• Business entity components

Data Layer Components

• Data access components
• Data helper and utility components
• Service agents

Services Layer Components

• Service Interfaces
• Message Contracts

You can read more about the components in our Cheat Sheet – Reference Application Architecture.

My Related Posts

• New Release: patterns & practices Application Architecture Guide 2.0 Beta 2
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• Services Layer