ALE (Application Link Enabling) is an SAP technology used to distribute and synchronize business data across multiple SAP systems within a distributed landscape. It is designed to maintain data consistency and loose coupling between systems — for example, distributing master data (like material, customer, or vendor) from a central system to multiple satellite systems such as warehouses or subsidiaries.
ALE uses IDocs as the data transport mechanism. The ALE layer manages the routing, control, and monitoring of these IDocs between systems. The configuration involves three main components:
Logical Systems: Unique identifiers for each SAP system in the landscape.
Distribution Model (BD64): Defines which message types should be sent from which system to which receiver.
Partner Profiles (WE20): Define communication parameters, ports, and processing function modules for IDoc transmission.
The ALE process typically involves generating an outbound IDoc in the sender system, transmitting it through the RFC (Remote Function Call) interface, and then processing it as an inbound IDoc in the receiver system. ALE also supports filtering and conversion rules, allowing selective data distribution.
In essence, ALE + IDoc work together to enable reliable, asynchronous, and automated data exchange across SAP landscapes — ensuring that distributed systems remain synchronized without manual intervention. This is crucial in large organizations with multiple SAP instances or hybrid SAP/non-SAP integrations.