An apparatus and system for generating KPIs based on packet delay performance measurements through a NG-RAN or 5GC are described. Integrated average UL and DL delays in NG-RAN, gNB DU delays and e2e delays are determined for each sub-network, network slice subnet, and network slice, and for a gNB DU. An overall NR cell DU delay including air interface delay and delay within the NR cell DU, and an overall gNB-CU delay including F1 interface delay and delay within the gNB-CU-UP, are each independently weighted for each gNB and in each direction for the integrated delay KPI in the NG-RAN. The e2e delay KPIs are average UL or DL delays between a UPF and UE(s) for a network slice based on e2e delays for each N-3 and N9 interface weighted by number of packets or data volume of the interface for the corresponding direction.