In an example embodiment, a topology based channel assignment method for mitigating contention between overlapping radio coverage areas in a wireless "mesh" network topology. A central controller compiles radio overlap information and executes a Tiered Graph Coloring Algorithm, which is used to mitigate contention between overlapping radio coverage areas. In general, the radio channel for each Channel Assignment Cluster (Basic Service Set) is selected so that the aggregate radio coverage area of the Channel Assignment Cluster does not overlap with the radio coverage areas of neighboring Channel Assignment Clusters and fixed interference sources. In the tiered algorithm, a Channel Assignment Cluster is represented as a single vertex, interference sources are represented as "fixed" vertices with fixed color assignments, and "overlapping" vertices are interconnected by "edges." Vertices are "tiered" so that overlap mitigation is prioritized for higher-traffic radios.