The considered problem is that of maximizing the degrees of freedom in cellular downlink, under a backhaul load constraint that limits the number of messages that can be delivered from a centralized controller to the base station transmitters. We first characterize the DoF for large Wyner's linear interference networks and show that the optimal assignment of messages to transmitters is asymmetric and satisfies a local cooperation constraint and that the optimal coding scheme relies only on zero-forcing transmit beamforming. We then extend the presented coding scheme to more general locally connected and two-dimensional networks, and show that a flexible backhaul design can offer DoF gains and simplification of existing schemes, without incurring additional overall load on the backhaul.