This presentation outlines the experience of the IESO in managing the Ontario Network Model. The IESO existing processes for gathering the network data from the market participant, validating the data, building the network model, and loading the network model into the energy management system (EMS) and market information system (MIS) are first outlined. Next the available tools for the network model data validation are presented and finally the impact of the network model on the operation as well as the electricity market is discussed. In conclusion, some desired tool features in managing the network model are presented.