Application Link Enabling (ALE) is the standard SAP tool of choice for linking an SAP system to another SAP system, to an application integration system like SAP XI, or to any subsystems, and for distributing data across such systems. However, it is all too easy for such distributions to cause reduced system availability and poor performance for other users and processes. To address these issues, you need to understand how ALE data distributions work — how they utilize work processes, how processing loads can be distributed, when and how to couple or decouple ALE processes, and when and how to use packets for processing. This article provides you with a foundation for that understanding by taking you through the data distribution process and identifying opportunities for controlling and optimizing it.