http://www.rfc-editor.org/rfc/rfc6552.txt
RFC 6552: Objective Function Zero for the Routing Protocol for Low-Power and Lossy Networks (RPL), P. Thubert2012-03-01T23:00:00-00:00This 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. [STANDARDS-TRACK]