This paper provides a detailed analysis and modelling of the Operational Expenditures (OPEX) for a network provider. The traditional operational processes are elaborated and the expected changes when using a control plane such as ASON/GMPLS are described. Control planes are promoted as a major technology for the automation of network operations. It is often claimed to allow the reduction of OPEX. However, detailed analysis and quantitative evaluation of the changes induced by such technologies is rare. In this paper we quantify the cost reduction potential of an ASON/GMPLS based control plane. Additionally, we show an important impact of the used resilience scheme on the expenses directly related to continuous costs of infrastructure (floorspace, energy,...) and on the planning and reparation costs. Concerning the service provisioning costs, we show that the introduction of a control plane leads to a reduction in
the order of 50% of the OPEX cost compared to the traditional case.