In one embodiment, a management device, such as a root node, monitors Internet Protocol (IP) overhead (e.g., IP header sizes during source-routing or route table sizes) within a directed acyclic graph (DAG) in a computer network. If it is determined that the IP overhead is above a configured threshold, then in response, a trigger is initiated to have devices within the DAG label-switch downward traffic directed away from the root node within the DAG. In another embodiment, a device communicating within a DAG stores IP routes corresponding to upward traffic from the device directed toward a root of the DAG, and IP-routes upward traffic based on the IP routes. Conversely, the device also stores labels corresponding to downward traffic from the device directed away from the root of the DAG, and label-switches downward traffic based on the labels, accordingly.