An apparatus comprising: means arranged to determine by a first network node of a user equipment that the user equipment is to be dual connected to the first network node and a second network node; means arranged to identify at least one radio configuration supported by the first network node from capability information of the user equipment; means arranged to send information to the second network node, the information comprising the capability information of the user equipment and the at least one radio configuration supported by the first network node and an indication of identifiers of at least one reference index identifying compatible configurations supported by the first network node and the second network node for a dual connection by the user equipment using at least one supported radio configuration within the capability information, wherein the capability information comprises an allowed list of indices of identified configuration combinations of the at least one reference index associated with long term evolution capabilities for the first network node and the second network node, and wherein each of the identified configuration combinations is tagged with at least one of a supported long term evolution or supported new radio band to indicate how each of the identified configuration combinations can be referenced by at least one of the first network node or the second network node for a dual connection; and means arranged to, in response to the sending, receive from the second network node an indication of a chosen at least one of the identifiers from the at least one reference index indicating at least one radio configuration of the at least one supported radio configuration for use by the second network node in the dual connection. means arranged to determine by a first network node of a user equipment that the user equipment is to be dual connected to the first network node and a second network node; means arranged to identify at least one radio configuration supported by the first network node from capability information of the user equipment; means arranged to send information to the second network node, the information comprising the capability information of the user equipment and the at least one radio configuration supported by the first network node and an indication of identifiers of at least one reference index identifying compatible configurations supported by the first network node and the second network node for a dual connection by the user equipment using at least one supported radio configuration within the capability information, wherein the capability information comprises an allowed list of indices of identified configuration combinations of the at least one reference index associated with long term evolution capabilities for the first network node and the second network node, and wherein each of the identified configuration combinations is tagged with at least one of a supported long term evolution or supported new radio band to indicate how each of the identified configuration combinations can be referenced by at least one of the first network node or the second network node for a dual connection; and means arranged to, in response to the sending, receive from the second network node an indication of a chosen at least one of the identifiers from the at least one reference index indicating at least one radio configuration of the at least one supported radio configuration for use by the second network node in the dual connection.