The Routing Protocol for Low-Power and Lossy Networks (RPL)
specification defines a generic Distance Vector protocol that is
adapted to a variety of network types by the application of specific
Objective Functions (OFs). An OF states the outcome of the process
used by a RPL node to select and optimize routes within a RPL
Instance based on the Information Objects available; an OF is not an
algorithm.

This document specifies a basic Objective Function that relies only
on the objects that are defined in the RPL and does not use any
protocol extensions.