Point-to-Point Direct Connection Design and Configuration in SAP Using NetWeaver Processing Integration 7.1
Direct Connection is when one system calls another system directly without using the Integration Server as a central instance. Communication takes place using the Web services runtime.
When applications are coupled tightly they can exchange messages directly - without a redirection through a middleware (like the Integration Server). However, this peer-to-peer message exchange can still be configured (technical address of the Receiver System, authentication, security settings etc) in one central place.