 delays (e.g. in the range of 10 seconds [18]) as users do not expect instant delivery. The use of TCP on the transport protocol layer means email is delivered without losses (because TCP retransmits all lost packets/segments, providing 100% lossless transfer). As for any Internet service, the data rate (i.e. bitrate) for the email transfer can be calcu- lated. The trigger points for the email mean data rate are given in Table 6.5. For example, QoS parameter email mean data rate [Kbit/s] [17] is defined with the following abstract equation: Email_data_transferred[kbit] Email_mean datarate = (6.2) (tsuccessful_email_transfer tstart_email_transfer)[s] The WWW is one of the most important Internet native best-effort services, which is standardized by the IETF. Like email, it is a non-real-time service. However, unlike email, the Web is an interactive service between HTTP client and HTTP server, where the HTTP server is always a machine, while the HTTP client can be operated by a human (e.g. via a Web browser, such as Chrome or Firefox) or a machine. In both cases, the required responsive time for the Web is in the range of approximately two seconds [18]. Although the bitrates are increasing over time, the Web pages are becoming heav- ier by using higher resolution for pictures and embedded videos, which influence the delay. The Web is based on the HTTP/TCP/IP protocol stack for transmission purposes between the HTTP client and the HTTP server, but the presentation of the Web con- tent is done by protocols implemented over HTTP on the application layer (e.g. HTML). With the use of TCP on the transport protocol layer, the Web is also lossless transmission because TCP (below the HTTP) handles retransmissions of all lost packets/segments. However, many losses in a given shorter period of time may case a low data rate for the Web connection, due to TCP behavior at multiple losses in a congestion window, which will cause reset of the bitrate to the initial value at the start of the TCP connection that uses the HTTP (which