  When evolved NodeB (eNB) flexible functional split is implemented in
Virtualized Radio Access Network (V-RAN) 5G systems, fronthaul connectivity
between the virtualized network functions (VNFs) must be seamlessly guaranteed.
  This study proposes the utilization of Software Defined Networking (SDN) to
control the mobile fronthaul. In particular, this study investigates the
ability of the SDN-based control of reconfiguring the fronthaul to maintain VNF
connectivity when cell and optical access turn into sleep mode (off mode) for
energy efficiency purposes.
  The evaluation of the proposed scheme is performed by federating two remote
experimental testbeds. Results show that, upon cell and optical access turning
on and off, the fronthaul reconfiguration time is limited to few tens of
milliseconds.

Networking and Internet Architecture