The optical network essentially provides point-to-point connectivity between two end equipments that are directly attached to optical network edge in terms of high bandwidth lightpath. Recently, there are lots of proposals to enhance intelligence of optical network as well as flexibility, reliability and scalability. However, it is difficult to validate, verify and evaluate these proposed protocols because they usually employ distributed control mechanism, which requires a huge network testbed. One alternative to expensive hardware is the use of computer simulations. In this paper, we constructed a functional and fault model for the transport plane of optical networks and implemented an Optical Network Simulator prototype on the basis of our model. Finally, using the developed tool, we have evaluated our design of Optical Network Management Protocol (ONMP), which is a Network-Network-Interface (NNI) optical network protocol in control plane.