The present invention relates to a method and an arrangement in a communication system in which a network management architecture comprises modules representing a virtual reality of network nodes (24) and network links under management. Organization of said modules and information contained in said modules are based on a pre-determined network management schema, whereby said network nodes (24) and said network links are managed by accessing and manipulating said modules. The network management schema is modified by reducing the amount of information in said modules. Then, the modified network management schema is used for managing said communication network system and thereby facilitating communication network system management.