Component Model 0 (CM-0) level illustrates interactions between target application and adjacent applications. All the relevant application services (or application interfaces) are introduced. The AM-1-level the diagram consists of enterprise architecture level components and their services, target application is in the middle. This level is the ground, the altitude zero, where the "buildings can be seen from their facades", not interiors. We can see what there is, but we can't see what is inside... We can also think that we are flying in a helicopter couple of hunderd meters above the ground, we can see the buildings, streets etc., but we cannot see the details - only roofs and objects...