Monitoring of the user Quality of Service: Network architecture for measurements, role of the user operating system with consequences for optical accesses

In this work, we illustrate our experiences on activities about monitoring of the User Quality of Services (QoS) measurement campaigns. We show the network architecture that has been implemented to achieve QoS tests on all Italian users. Such a network permits to achieve a detailed investigation on the network causes that induce performance degradation and, therefore, it can be assumed as a basis for networks' behaviour investigation. We also show how operating systems play a key role on the performance degradation: in particular, our end-to-end File Transfer Protocol (FTP)-based bandwidth measurements point out the strong impact of TCP (Transmission Control Protocol) implementation. As a consequence, a testing scenario needs to be described not only according to the physical parameters, but also paying attention to software implementation factors that could affect the testing results. The difference in terms of QoS due to the operating system increases with the user bandwidth and therefore this will be a fundamental topic for optical fibre accesses.