1. A method for managing data transmission according to a Quality of Service (QoS) in a network assembly by a QoS architecture implemented in the network assembly, wherein the network assembly is provided with a plurality of host devices organized in a domain structure, each domain of the domain structure comprising a QoS managing device assigned to the domain, and wherein the method comprises the following steps managed by the QoS architecture using for information exchange a signal protocol: for a proposed data transmission over the network assembly to a receiver host device, a resource request information is provided from a requesting host device to a receiving QoS managing device, in response to the resource request information, a response information is provided from the receiving QoS managing device to the requesting host device, wherein the response information comprises one of a resource reservation information indicating a resource reservation and a failure reservation information indicating a failure to reserve the requested resource, if the resource reservation is made, the resource reservation is maintained by a maintaining mechanism implemented by the QoS architecture, and the resource reservation is terminated after a termination is initiated by one of a termination information received by the receiving QoS managing device from the maintaining mechanism, a termination request provided by the requesting host device to the receiving QoS managing device, and a termination request provided by the QoS managing device by itself.