A mobile router is configured for attaching to a selected router in a clustered network (e.g., a mobile ad hoc network) based on identifying a network topology model of the clustered network from received router advertisement messages that include tree information option fields specifying attributes of the network topology model. The mobile router selects which router advertisement originator to attach to based on correlating the attributes of the router advertisement originators relative to identified priorities, and orders the router advertisement originators within a default router list based on the identified priorities. If the mobile router detects a router from a second clustered network, the mobile router advertises to the attachment router that the second clustered network is reachable, enabling the two clustered networks to communicate using a point-to-point link between the respective attachment routers.