Reflective QoS

Let the Network Teach the UE

Reflective QoS is a clever mechanism that reduces signaling overhead for QoS rule installation. Instead of the network explicitly telling the UE which QoS rules to use via NAS signaling, the UE learns by observation. When the network sends downlink packets with a specific QoS treatment and sets the RQI (Reflective QoS Indication) bit in the GTP-U header, the UE automatically creates a matching uplink QoS rule. The UE essentially mirrors the downlink QoS treatment for the uplink direction, deriving the packet filter and QFI without any additional control-plane messaging.