A resource orchestration entity and a method for enabling end-to-end service reliability and availability with service flow differential deployment of a network service (NS) with one or more service flows in an NS chain comprising one or more network function nodes coupled via a plurality of intermediate networking nodes. The resource orchestration entity is arranged to obtain an information element of service availability level in at least one descriptor for defining the service availability level requirements of the service flow from an NS management entity, and provide the information element of service availability level together with an identification reference of the service flow to a resource management entity for assigning resources comprising network function nodes and their inter-connections in virtual network laying on the network hardware comprising networking nodes when instantiating the NS comprising service flows in the NS chain.