1.1 QoS definition

ITU*^[1] defines QoS as the “totality of characteristics of a telecommunications service that bear on its ability to satisfy stated and implied needs of the user of the service”*^[2].

QoS experienced by end-users, QoS required or expected by end-users, QoS planned by Service Providers and QoS delivered by Service Providers do not necessarily converge. Despite great efforts from the Service Providers to attempt to provide high QoS levels, QoS experienced by end-users may still be low and much lower than QoS expected by end-users. Making these 4 levels of QoS match together can be very challenging.

While QoS experienced by end-users and QoS required or expected by end-users can be better assessed thanks to customer surveys, measuring QoS delivered by Service Providers can better inform end-users. QoS can be measured by objective means such as level meters, delay counters, etc.