This paper describes the design and implementation of a middleware for a framework dedicated to Augmented Reality/Mixed Reality (AR/MR) applications. The goal is to offer an environment for the development of distributed applications running on mobile devices (wearable computers and/or smartphones). The paper first presents the main needs of an AR application and introduces the necessity of distribution in this field. Then we make a quick overview of existing distributed AR frameworks. The goal of this overview is to extract main features and strengths of each framework's architecture based on a set of defined criteria. This comparison being meant as a starting point to extend our own framework (ARCS: Augmented Reality Component System), the last section is about the design and implementation of our own software infrastructure for transparent distributed Augmented Reality taking in consideration our own goals and constraints and taking profit of the strengths of the studied existing frameworks.