Sap XI sld products and software component.

Hello everybody.

I'm studying the sap/xi module and i got some difficulties to understand the products that we configure in the SLD repository and directory.

My question is: if i add a component in my sld let's say sap 4.7 then should this component first exist as a system with it's software components ? so it is a correlation i configure only the sap/r3 or non sap systems that we are using and we want to interface with.

Thanks for your help

Tahar.