Using ALE with SOP 
Communication between applications in ALE is carried out via the medium of the IDOC (intermediate document). In SOP, the configuration of all information structures for use in ALE is based on one central reference IDOC. This has ten segments for key figures, one segment for characteristic values, and one segment for the planning version.
You maintain a distribution model for the IDOC of each information structure, in which you define the reference as the sender and the client as the receiver. You can then set up this distribution model such that organizational units (characteristic values) receive only data (key figures) which is relevant to them. For example, you specify that sales organization Florida is to be sent its own target sales quantities but not the target sales quantities of sales organization Texas, and not the total target sales quantities for all sales organizations. You configure distribution models in Customizing for Application Link Enabling.
In order to be able to send the data of a particular information structure, you must have the system generate a message type for it. You do this in Customizing for Sales & Operations Planning (in "Application Link Enabling" under "Functions"). This ensures that an IDOC containing planning data is transmitted to the receiver whenever the data of this information structure is saved. This may be a sales plan, a production plan, or any planning data saved in an information structure. Previous planning data at the receiver location is overwritten in this process. Thus, if the user wishes to resend data for any reason, he or she must call up the planning data and save it. All message types generated for Sales & Operations Planning have the format "LIPxxx" (xxx stands for the three figures after the leading "S" in the name of the information structure).
At the receiving end, the Workflow Management module records the arrival of an IDOC, checks its date, and ensures that the most recent data is saved. If subsequently it is decided that the older data is needed after all, it has to be sent again.
The information structure must be present both centrally and locally so that characteristic values can be recognized on both sides.
It is possible to define a line in the planning table such that it is not ready for input, for example, such that planning figures set centrally cannot be changed decentrally.
For full information on ALE, see:
ALE Consultant’s Guide
Implementation Guide for Application Link Enabling