Reg. the Business Service and Business System(Integration Directory).

Hi,

I have a small doubt reg. the Business Service and Business System. When do we need to go for creating a Business Service AND a Business System? I want to know the difference b/w them and the usage of a Business Service as compared to a Business System. Generally I create Business Systems in my configuration scinerioes. Could anybody pl. clarify on this?

Regards,

Murthy