Control-Plane Traffic Modelling for Connection Management in T-SDN Optical Networks using Transport PCE and OpenROADM

A crucial component of the architecture of software defined networks is the control plane. With the increasing traffic demand and traffic dynamics, the scalability and resiliency of the control plane infrastructure gains importance. While there is a plethora of studies being performed on control plane optimization for packet-switched networks, these issues are yet to be thoroughly explored for software defined transport networks (T-SDN). Control plane optimization involves not only the placement of controllers, but also the appropriate design of the signalling network (the so-called DCN), which requires knowledge of the control traffic demand. In this paper, considering a T-SDN based network scenario comprising Transport PCE controllers and OpenROADMs, we focus on the modelling and evaluation of the control traffic that stems from the signalling procedures for lightpath setup and teardown. Our modelling framework unveils the control traffic dependency on the number of transponders and Reconfigurable Optical Add/Drop Multiplexers (ROADMs) involved in the setup and teardown of optical connections. Furthermore, the proposed framework paves the way for the design of resilient DCNs for disaggregated T-SDN enabled optical networks.