Separation of Business Systems and Technical Systems
Business systems represent “logical” systems, whereas technical system descriptions contain information about the technical details of a system. This is information such as the server address. When the message flow - that is, the routing - in a system landscape is defined (in the receiver determination), this is done based on business systems, that is, at the level of the “logical” systems. This separation of the routing definition from the technical details has the advantage that the configuration is independent from any changes to the technical details of the system landscape. If, for example, a server address is changed, this has no impact on the routing configuration.
Nevertheless, at runtime a message needs to be forwarded to a “real” (physically) installed system. That means that the server address has to be known at runtime. Therefore, in addition to the “logical” receiver determination (as mentioned above), a “technical” receiver determination is performed at runtime. This technical receiver determination is accomplished by a mapping of the business system to the underlying technical system. This dependency is already defined in the SLD since you always have to assign a technical system when creating a business system.
As an example, this mapping of a business system and technical system shows up in the configuration data in the Integration Directory in the attributes of receiver communication channels that usually contain the server name of the receiving system. The server name is part of the technical system description that is maintained in the SLD. On the other hand, the communication channel is assigned to a (receiver) communication component which is mapped directly to a business system from the SLD.