Method for the implementation of network functions virtualization of a telecommunications network providing communication services to subscribers of the telecommunications network, wherein the telecommunications network comprises a virtualized network part comprising virtual hardware appliances, and a non-virtualized network part comprising physical hardware appliances, wherein the telecommunications network furthermore comprises a first set of capability information and a second set of capability information, the first set of capability information being indicative of first capabilities of the virtualized network part, the second set of capability information being indicative of second capabilities of the non-virtualized network part, wherein with respect to a special communication service and regarding network function requirements of the special communication service - the special communication service being requested or at least able to be requested by at least one subscriber of the telecommunications network -, the method comprises the step of determining whether the first capabilities and/or the second capabilities match the network function requirements of the special communication service, wherein -- in case that only the first capabilities match the network function requirements of the special communication service, the special communication service is provided, by the telecommunications network, using the virtualized network part, -- in case that only the second capabilities match the network function requirements of the special communication service, the special communication service is provided, by the telecommunications network, using the non-virtualized network part, -- in case that both the first and second capabilities match the network function requirements of the special communication service, the special communication service is provided using one of the virtualized network part and the non-virtualized network part, or partly the virtualized network part and partly the non-virtualized network part, wherein the method further comprises the steps of: -- storing in a database_HA functionality and characteristics of the physical hardware appliances corresponding to the second set of capability information; -- storing in a database_VA the network functions implemented by the virtual appliances corresponding to the first set of capability information; -- storing the network functions and their associated characteristics which are required in a required network functions cache_RNF; -- determining by using databases HA and VA the differences in functionality between the physical and virtual appliances in a third processing step, with the characteristics associated with each function also being recorded; -- synchronizing this to each update of database_VA, with the result being stored in cache_DF; -- using cache_RNF and cache_DF to determine - in the fifth processing step - whether one or both of the virtual and physical hardware appliances has the functionality for each required function and the characteristics required for the execution of the device service or application and its associated traffic. -- in case that only the first capabilities match the network function requirements of the special communication service, the special communication service is provided, by the telecommunications network, using the virtualized network part, -- in case that only the second capabilities match the network function requirements of the special communication service, the special communication service is provided, by the telecommunications network, using the non-virtualized network part, -- in case that both the first and second capabilities match the network function requirements of the special communication service, the special communication service is provided using one of the virtualized network part and the non-virtualized network part, or partly the virtualized network part and partly the non-virtualized network part, -- storing in a database_HA functionality and characteristics of the physical hardware appliances corresponding to the second set of capability information; -- storing in a database_VA the network functions implemented by the virtual appliances corresponding to the first set of capability information; -- storing the network functions and their associated characteristics which are required in a required network functions cache_RNF; -- determining by using databases HA and VA the differences in functionality between the physical and virtual appliances in a third processing step, with the characteristics associated with each function also being recorded; -- synchronizing this to each update of database_VA, with the result being stored in cache_DF; -- using cache_RNF and cache_DF to determine - in the fifth processing step - whether one or both of the virtual and physical hardware appliances has the functionality for each required function and the characteristics required for the execution of the device service or application and its associated traffic.