  The work described in this paper explores the use of time and synchronized
clocks in centrally-managed and Software Defined Networks (SDNs). One of the
main goals of this work is to analyze use cases in which explicit use of time
is beneficial. Both theoretical and practical aspects of timed coordination and
synchronized clocks in centralized environments are analyzed. Some of the
products of this work are already incorporated in the OpenFlow specification,
and open source prototypes of the main components are publicly available.
