In a system landscape with multiple back-end systems, users may need to access several instances of the same Web Dynpro application or transaction originating from different back-end systems.
The following figure shows a system landscape where a user accesses a Web Dynpro application or a transaction that may originate from either of two back-end systems.
You can provide the SAP system alias at either of the following locations:
In a target mapping (see Configuring Target Mappings)
In transaction LPD_CUST (see Customizing Navigation Targets in LPD_CUST)
In the sap-system parameter in the URL
If you provide the sap-system parameter in the URL, this overrides any SAP system settings in the target mapping or in transaction LPD_CUST.
You can add the sap-system parameter to the URL by providing it in the tile configuration (see Configuring Multiple Back-End Systems Using the sap-system Parameter)
If you provide a system alias in transaction LPD_CUST, it must match the name of the RFC destination as defined in transaction SM59.
If you add the sap-system parameter to the URL, it must match the SAP system alias name as defined in Customizing for SAP Gateway (see Customizing activity Manage SAP System Aliases).
We recommend to keep these alias names in sync.