1. A method, comprising: determining a current path cost in a routing topology from a particular node in a shared media communication network to a root node of the routing topology via a current parent node; determining, for each reachable potential parent node of the particular node, a respective path cost from the particular node to the root node via each potential parent and a respective link metric from the particular node to each potential parent node; determining a set of acceptable parent nodes selected from the potential parent nodes, wherein acceptable parent nodes have a respective path cost that is less than the current path cost plus a cost increase, and also have a respective link metric from the particular node that is within a link metric range; determining, for each acceptable parent node of the set, a respective number of child nodes of the corresponding acceptable parent node; and selecting a new parent node for the particular node in the routing topology based on giving preference to acceptable parent nodes having a greater respective number of child nodes.