Layered architecture revisited — Comparison of research and practice

Organizing a software architecture into layers has been one of the earliest architectural styles ever used. Even today layered structure is a very common architectural style used in various industrial systems. However, we have observed that the usage of layered architectural style varies greatly in different contexts. This paper aims to compare the notion of software architecture layers in research literature as well as in industrial practice. Firstly, we performed a systematic literature review of research articles on layered software architectures; we also reviewed selected books of software architecture. Secondly, to understand the practice, we investigated a number different recent architecture documents to cover the current usage of layered architectures. Our results indicate that there is very little actual research done on layered architectures. The current usage of layered structures seems to be more complex than reported before. This gap between the research and practice needs to be bridged by researchers.