System
These systems are the SAP NetWeaver Gateway hub systems configured in 
SPRO 
SAP NetWeaver Gateway Service Enablement Backend OData Channel Connection Settings to SAP NetWeaver Gateway SAP NetWeaver Gateway Settings in the Gateway. 
Client
The client of the SAP NetWeaver Gateway hub system.
RFC Destination
The RFC destination of the SAP NetWeaver Gateway hub system.
Registration Status
Indicator that represents the registration status of the service in the selected system. The statuses are as follows:
Service Registered from this system - The service is registered from the current system.
Service with the same name registered from another system - There may be instances when a service with the same name as your service is already registered in the target SAP NetWeaver system. In such instances this status is shown.
Service not registered - The service is not yet not registered in this system. You can proceed and register the service in the current system.
Could not retrieve the registration status - There may be instances when the target system's status could not be retrieved due to some technical reasons, for example, due to system unavailability or authorization failure.
