Logical System Names
When data is distributed between different systems, each system within a network has to be clearly identifiable. The "logical system" deals with this issue.
A logical system is an application system in which the applications work together on a common data basis. In SAP terms, the logical system is a client.
Since the logical system name is used to identify a system uniquely within the network, two systems cannot have the same name if they are connected to each other as BW systems or as source systems, or if there are plans to connect them in any way.
Although SAP does not recommend that you connect test systems to production systems, a test system can have the same name as a production system. This makes copying production systems to test systems a lot simpler.
You are only allowed to change the logical system name of a system if the system is not connected to any other systems, because changing the logical system name would render all the connections to other systems useless.
In BW, you make the settings for the logical system names in the BW Customizing Implementation Guide under Business Information Warehouse → Connections to other Systems → General Connection Settings. In the source system, you make the settings for the logical system in the Implementation Guide under Cross Application Components → Distribution (ALE) → Basic Settings.
Note SR047 lists names that cannot be given to BW systems, because they are reserved for internal use.
<System-ID>CLNT<Client>