A non-transitory computer readable media, methods, system and network function virtualization orchestrator can be used to instantiate a network service operating as at least a portion of a network slice. A network service descriptor describing the network service comprises at least one service deployment flavor; zero or more sharing allowed attribute defining if the network service or constituent instances of the network service is allowed to be shared with another network service instance, or with its constituent instances; and zero or more external placement rule attribute defining if the network service or constituent instances of the network service, is affine or anti-affine with current and future other network service or constituent instances of the current and future other network service.