We study the capacitated m-ring-star problem (CmRSP) that faces the design of minimum cost network structure that connects customers with m rings using a set of ring connections that share a distinguished node (depot), and optionally star connections that connect customers to ring nodes. Ring and star connections have some associated costs. Also, rings can include transit nodes, named Steiner nodes, to reduce the total network cost if possible. The number of customers in each ring-star (ring's customers and customer connected to it through star connections) have an upper bound (capacity).These kind of networks are appropriate in optical fiber urban environments. CmRSP is know to be NP-Hard. In this paper we propose an integer linear programming formulation and a branch-and-cut algorithm.Fil: Berinski, Hernán. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Computación; ArgentinaFil: Zabala, Paula Lorena. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Computación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina