In this paper, we investigate on conceiving reliable fixed broadband wireless networks under outage probability constraints. We introduce a joint model of data routing and bandwidth assignment that minimizes the total renewal fees of licenses. This problem differs from classical capacity planning since the capacity of microwave links is prone to variations and, hence, we must deal with random parameters to guarantee a desirable reliability level of the solution. We introduce a chance-constrained programming approach to tackle this problem and derive integer linear programming (ILP) counterparts. We further propose cutset-based valid inequalities to enhance the performance of ILP solvers. Computational results illustrate the price of reliability and present a comparative study on the performance of the different formulations.