 book) is coming from fixed broadband access. This is due to higher bitrates of fixed broadband, but also due to the fact that many users access the Internet by using mobile devices (smartphones) via WiFi which is typically connected via fixed broadband access lines to the Internet. So, in most, WiFi access is in fact fixed broadband Internet access, although the WiFi technology has its influence on the experienced QoS because it uses unlicensed spectrum, which is crowded, and it experiences much higher deviation of signal strengths and with that, deviation in the available bitrates between the user WiFi interface and the access point on the side of the network connected to the Internet. The growth in mobile data traffic is not driven only by an increase in the number of subscribers. It is influenced by different factors such as availability and affordability of powerful mobile devices (e.g. leading-edge smartphones), deployed mobile networks with high capacity per mobile user, and the OTT applications and services ecosystems developed for mobile devices (resulting in increased use of download or upload of var- ious mobile data). With increased broadband penetration the broadband market is sat- urating because all human users have either fixed or mobile Internet access, or both. That is why although the overall volume of Internet traffic is increasing, its growth rate is declining over time. The growth rate is most important for business because it is important how much a given business can grow in the near future. Higher growth attracts investments in that sector and vice versa. The revenues of fixed and mobile operators are saturating regarding their growth, due to saturation of the market and the already developed com- petition (e.g. in each country there are multiple fixed and mobile operators that share the ICT/telecom market). For example, fixed voice revenues have started to decline around 2005 when the number of subscribers showed a downhill trend (which was caused mostly by higher penetration of mobile v