There’s a lot of KPI should be considered to monitor the network, for NSS it’s divided into 3 part which are : 1. Performance KPI which included ASR (Answer to Seize Ratio), NER (Network Efficiency Ratio), LUSR (Location Update Success Rate), PSR (Paging Success Rate), Inter MSC HO Success Rate, Security Operation Success Rate, PDD. 2. Utilization KPI which included Signaling Load, Trunk Occupancy, Processor Load, VLR Subscriber. 3. Availability which inculuded MSC/VLR Availability, Trunk Availability and Signaling SS7 Availability. For IN and SMS i just know a little bit such as : IN Success Call Rate, SMS Success Delivery Rate. Hope it will help you..