The Atrium project was created to solve two major challenges in the development of a dynamic ecosystem. The first challenge is the rift existing between the elements required to build a hybrid SDN stack. In various layers of the stack, there are missing pieces that lead to a low integration. The second challenge lies in the fact that there is a gap in interoperability.

These challenges are found in inter-vendor interoperability and at the protocol level with interfaces being under-specified or over-specified. For instance, a connection between a switch and a controller can be affected by the number of versions of OpenFlow currently defined and the complexity of deciding what to use.

Atrium solves both challenges by instantiating and integrating a set of production quality components. ONOS is a key component in the initial distribution of Atrium. It has released the second ONOS-based Atrium route in 2016. Its architecture can be found as follows: