A layer is a logical grouping of packages. One or more packages can be combined into one of more layers.
A layer also contains the order in which these packages should be executed. An example of such a layer could be the “Desktop Silo” which, for example, contains the Microsoft Office package and the Microsoft Terminal Server package. Layers are organized in a hierarchical tree structure.
Note: Packages added to the parent layer are NOT inherited by the child layer(s). An example of a layer structure is shown below.