1. A method in a mobile router configured for establishing communications within an ad hoc network, the method including: establishing concurrent attachments to respective attachment routers based on having received respective advertisement messages specifying respective parent depths relative to a clusterhead of the ad hoc network; selecting an advertised depth relative to the clusterhead based on adding a prescribed increment to a maximum one of the parent depths, and advertising reachability to the clusterhead based on outputting a router advertisement message specifying the advertised depth relative to the clusterhead.