Abstract Software Defined Networking (SDN) substrates are basic enabler for the network virtualization. They provide many opportunities but also require new solutions for well known legacy mechanisms. Thus, in this paper we present an innovative network monitoring tool which is able to operate with the usual available OpenFlow controllers. The presented tool extends the controller monitoring capabilities by providing utilization charts and statistics up to a flow level. In order to present the feature set, the tools architecture and implementation will be introduced. Further, an evaluation on a virtualized Mininet network using Open vSwitch is presented as well as an evaluation on our SDN research cluster with a typical data center fat tree topology composed out of NEC IP 8800 switches.