1. A method of operating a Network Function Virtualization (NFV) Software Defined Network (SDN) to perform a network task for an International Mobile Subscriber Identity (IMSI), the method comprising: an NFV management system directing an NFV orchestration system to install a virtual Probe (vProbe) with filter criteria for the IMSI to collect IMSI Key Performance Indicators (KPIs) in the NFV SDN for the network task; the NFV orchestration system directing an NFV Infrastructure (NFVI) to install the vProbe; the NFVI on-boarding the vProbe; the vProbe sending the filter criteria for the IMSI to a virtual Switch (vSW) in the NFV SDN; the vSW applying the filter criteria for the IMSI to Virtual Network Function (VNF) traffic and transferring the filtered data for the IMSI to the vProbe; the vProbe processing the filtered data for the IMSI to generate and transfer the IMSI KPIs to the NFV management system; and the NFV management system processing the IMSI KPIs to perform the network task.