The acronym QoS stands for the technical term ‘Quality of Service’. QoS defines specific quality requirements which must be met to use a communication service with the desired quality from the subscriber’s perspective. In order to meet these requirements, different actions, parameters and processes are defined depending on the network used or the transfer method, summarised under the term QoS. One can essentially distinguish between the transmission quality and the traffic quality. Whilst the traffic quality primarily pertains to the transmission technology and establishing the connection, the transmission quality pertains to the actual information transfer over a network.