Methods and network devices are disclosed for traversal, within a network configured for bit indexed forwarding, of a subnetwork having nodes not configured for bit indexed forwarding. In one embodiment, a method includes receiving, from a next-hop upstream node configured for bit indexed forwarding, an incoming tree descriptor message comprising a tree identifier and a descriptor bit array. Bit values in the descriptor bit array identify intended destination nodes to be reached via a network tree identified by the tree identifier. The embodiment further includes replicating and modifying the incoming tree descriptor message to generate an outgoing tree descriptor message for a next-hop downstream node within the network tree. In addition, the embodiment includes sending the outgoing tree descriptor message to the next-hop downstream node and sending to the next-hop upstream node a local label allocated to the tree identifier.