Apparatuses and methods in a communication system are provided. A method comprises receiving a service request comprising service requirements; determining, based on the service request, service level specification of the request, the service level specification comprising performance parameters and network functions to support the requested service; normalizing the determined service level specification by scaling the performance parameters according into a given normalization model of the network to obtain normalized service level specification; determining, based on the network functions and the given normalization model, normalized performance capability of the network functions and a configuration of a network slice supporting the requested service; comparing the normalized service level specification to the normalized performance capability; and determining, based on the comparison, whether the requested service can be realized with the network slice, and if so, create the slice.