This paper considers a routing problem for virtual circuit data networks with unreliable links. The problem is analyzed by transforming it into a stochastic multicommodity flow problem with recourse to find the optimal route set ( primary and secondary routes for all origin-destination pairs) that minimizes the expected average packet delay. Both the Lagrangian relaxation and the aggregate stochastic subgradient optimization methods are used to find the optimal solution ( route set) for which a stochastic version of the K( 0)-ordering method is newly exploited to find the initial feasible solution.