The primary function of a network management system (NMS) is to monitor, manage, and maintain computer networks. An NMS provides tools for diagnosing network issues, optimizing performance, and ensuring security. Key functions include real-time monitoring of network traffic, fault detection, performance analysis, and configuration management. By utilizing an NMS, organizations can enhance network reliability, proactively address issues, and ensure efficient functioning of both local and wide-area networks, leading to improved productivity and service delivery.