r to all data that is requested by IAS subscribers/end-users from various content providers and application/service providers globally on the public Internet which are referred also as OTT services (they include various websites, YouTube, Facebook, Twitter, BitTor- rent, OTT VoIP services such as Skype or Viber or WhatsApp, OTT cloud services such as Amazon clouds or Google docs, OTT video streaming such as YouTube). The most important QoS parameters for data services are referred here as KPIs for data. Main KPIs for data services together with the most popular data service/application types are given in Table 7.6 [11]. The table gives the importance (or in other words, rel- evance) of a given KPI for given data application/service type. The importance of KPI goes from very low (not SO important) to high (very important). The wording "appli- cation/service" is used, where typically application is a standalone implementation of a client application and a server application which communicate over the public Inter- net (either they are standardized or proprietary applications), while service refers to the applications which also include control and signaling data exchange (e.g. with different servers or network nodes) for the provision of a given service (e.g. each OTT VoIP is a service because there is mandatory required control data exchange, at least transfer of user's IP address to bind it with his/her username for delivery of terminating calls to that user by other users of the same OTT VoIP service). Considering the importance of the KPIs for data applications/service, high impor- tance of packet loss means having zero losses, which are provided by using TCP/IP protocol stack where TCP uses retransmissions to recover from any packet losses or errors. So, with TCP on the transport layer given service/application receives error-free data in both directions. In the cases where the delay KPI has high importance (e.g. for gaming services) then application may provide retransmissions when needed and utilize 7 Broadb