Network operators are facing hard competition for opportunities in the telecommunications market, forcing network investments to be carefully evaluated before the decision-making process. A great part of core network operators’ revenues comes from the provisioned connectivity services. Taking this premise as our starting point, we first examine the provisioning of differentiated services in current shared-path protection (SPP) environments. This analysis reveals that current resource assignment policies are only able to provide a very poor grade of service to the supported best-effort traffic. Aiming to improve this performance, a novel resource partitioning scheme called diff-WS is proposed, which differentiates those wavelengths supporting each class of service in the network. As a major goal of this paper, the benefits of diff-WS over current resource assignment policies are assessed from an economic perspective. For this purpose, the network operator revenues maximization (NORMA) problem is presented to design the optical network such that the operator’s revenues are maximized. To solve NORMA, we derive statistical models to obtain, given a certain grade of service, the highest traffic intensity for each class of service and resource partitioning scheme. These models turn NORMA into a nonlinear problem, which is finally addressed as an iterative approach, solving an integer linear programming (ILP) subproblem at each iteration. The obtained numerical results on several network topologies illustrate that diff-WS maximizes resource utilization in the network and, thus, the network operator’s profit.