Abstract
This paper addresses an interworking model of transport network controllers including SDN and Non-SDN controllers. It has an overview of recent research and standard activities, classifies types of transport network controllers, and proposes a SDN and Non-SDN interworking model. For verifying the proposed interworking model, it leads to a 3-tiers reference model from the interworking architecture that is widely being used in interworking modelling of SDN controllers.