For each meta-model layer we can distinguish one or more model layers of two
types: service layers and realisation layers. A service layer exposes functionality
that can be ‘used by’ the next higher layer, while a realisation layer models shows
how the consecutive service layer is ‘realised’. The number of these layers is not
fixed, but a natural layering of an ArchiMate model will contain the succession of
layers depicted in Fig. 8.4.