QCI
QoS Class Identifier
A technology feature of 4G and 5G networks that allows some traffic to have higher priority than others. It is one of the core QoS (Quality of Service) features of 4G and 5G networks. (In 5G networks, QCI is referred to as 5QI.)
See: QoS
Different users of a mobile network may have different standard QCI numbers assigned, giving them an effective priority in accessing the network. (Lower numbers have higher priority.) Customers on prepaid and other cheap plans typically have the lowest priority. Customers on pricier premium plans often have higher priority. The very top priority level may be reserved for first responders.
Customers on "unlimited" data plans may actually have a monthly allotment of "premium" data at one priority level, after which they drop down to a lower priority level.
Priority levels are most important when a network is very congested/busy.
Related QoS technologies can give different priority to different types of traffic, allowing some delay for web browsing or texting traffic, while ensuring a voice or video call stays as close to real-time as possible.
