net traffic interconnections, there is growing influence of the trends which have appeared with the appearance of the broadband and ultra-broadband access (they have increased the expectations regarding the quality experienced by the customers, including the bitrates and delay). So, the trend is that the global service providers (Google, Apple, Amazon, Facebook, etc.) have started to deploy and operate 100000 80000 60000 40000 20000 Figure 7.3 Growth of number of autonomous systems. 7.3 Interconnection and QoS their own globally distributed networks and/or service centers to increase QoE (quality for their services experienced by their customers), by using CDNs also. Traffic forecasts show that more than 70% of all Internet traffic will cross CDNs by 2021 on a global scale, which is up from 52% in 2016 [3]. Additionally, large content and/or application providers (e.g. Google and Apple) operate some of the largest data transport networks in the world. However, they typically lack local Internet access networks (fixed or mobile) which are provided by national telecom operators based on national regulations in each country. However, large global service providers which build their own networks act also as network operators (i.e. network providers) and hence can negotiate their own peering and transit arrangements by using their role as network operators which is in favor of delivery of their global services with higher QoE. The high QoE is one prerequisite for the global service providers to keep and extend their customer base and to develop new innovative services provided over the global Internet network. 7.3.3 End-to-End QoS and IP Networks Interconnection The QoS by definition is always considered end-to-end, for each service. For services used by human users the whole concept of QoS is targeted toward satisfaction of user needs and expectations from the given ICT service. So, the big picture for QoS is always end-to-end, which includes all networks and networks segments on the path as well as all interconnecti