Architecture (Advanced Adapter Engine Extended) 
The following figure shows the main components of the AEX:
The main components for design and configuration time are the Enterprise Services Repository (ES Repository) and the Integration Directory.
Note
The Integration Directory installed with AEX contains the same subset of configuration options as that which is necessary to configure the AAE-only message processing option in a dual-stack PI installation, basically the integrated configuration.
Using these tools, an integration expert can design integration content (for example, interfaces and process integration scenarios) and specify the configuration settings for message exchange for a specific system landscape. The design and configuration tools are connected to the System Landscape Directory which contains, for example, the description of software components and systems.
More information:
Based on the configuration settings from the Integration Directory, messages are exchanged between the connected business systems at runtime. AEX uses the Advanced Adapter Engine as runtime engine.
To process messages, the AAE uses information from the Integration Directory. This information is made available to the AAE using a runtime cache.
More information: Runtime Caches