Abstract: The invention relates to the provision of services in communications systems comprising at least a first and a second sub-network, in which different switching technologies are used. According to the invention, information, which is relevant to configuration and describes the functions of network elements is saved globally for the sub-networks to a network element database. When a service is established, modified and/or cancelled, network elements are configured by a network operating system, which accesses information that has been saved to the network element database.