This article presents layer types as a concept for modeling arrays of communication objects. In a sense, layer types can be considered a generalization of array types. If the components of a layer are of a class type, the identifiers of component fields and methods can be lifted to the layer type level such that the lifted identifiers can be used to access all respective layer fields or layer methods by dot notation. This facilitates usual programming tasks. In addition, by employing predefined layer methods based on flags, functions, and relations over indices, layer types open up the way for a flexible and concise modeling of networks of communicating objects.