will remain customers of that service and hopefully the customer base will increase (if it has not reached saturation point where almost all possible users have already become service customers). On the other side, network neutrality prohibits OTT service differentia- tion in the access networks for the IAS. However, Internet traffic is transferred over the same links with traffic from managed IP networks (e.g. carrier VoIP, IPTV, criti- cal IoT services), hence QoS differentiation is certainly applied in the core and transit networks. Overall, striking a sensible balance in QoS approaches is not always easy. For example, considering the business side of national telecom operators, QoS-enabled services require higher investment and higher operational costs due to QoS functions in the networks. One should note that IAS is also an QoS enabled service, while individual OTT services and applications (provided over the IAS) are not. Additionally, there is a trend to invest in ultra-broadband networks, and targeted individual speeds in the 2020s are at least 100 Mbit/s over both fixed and mobile access networks. Most of that capacity is in fact for IAS (two-thirds of that is for video traffic over the Internet), then for IPTV (over managed IP networks), and the least for carrier-grade VoIP and other specialized (i.e. managed) services (over managed IP networks). Network neutrality is often considered to be the key driver of innovation in the appli- cation and service space. It appeared with the public Internet, SO from the outset the Internet was based on a network neutrality principle and best-effort approach for service provisioning. However, since the 1990s, with the convergence of telecommunication networks and services toward all-IP networks and services based on Internet technolo- gies, there is a need for end-to-end QoS provisioning in the new all-IP environment. That is necessary for legacy telecommunication services which are now provided over IP networks (managed IP networks) such as carrier grade VoIP and IP