Network Management has become a critical issue particularly in heterogeneous environment and multivendor computer networks. Client-servers with a large of computers need network management to manage and control the networks and components of networks. It is a case study at an energy company employee various platform that running multiprotocols. Company has main office and support offices in Jakarta and fields. Each office (site) has Local Area Network (LAN) and all of them were connected through Wide Area Network. Network growth rapidly and consequently the network performance decreases especially for Wide Area Network. First stage of study is investigation problem and learn from the literature related to problem. Second stage was try and run Network Management Platform Openview and setup the parameter and display. Data was acquired to support the analysis and eventually giving the solution. The parameter that was choosen for data acquisiton were utilization and traffic which are belong to performance management. Data was acquired at main router that makes connections between Jakarta-Fields, Jakarta-Headquarter and Jakarta to other Jakarta sites. The links that were located at serial ports of router were captured in realtime mode in the work time and rest time and then were displayed in graphics. Some references made a criterion for network performance evaluation based on utilization.