3GPP 23.501 v20.2.0 — the document's own text
5.44.3.3 Non-3GPP QoS Assistance Information
Taught in 24. Networks that are not for everybody (The 5G system architecture, in depth).
QoS experienced by a PINE connected behind a PEGC depends on the end-to-end path between the PINE and the DN, i.e. depends on the QoS differentiation in both the 3GPP network and the non-3GPP network attached to the PEGC. Non-3GPP QoS Assistance Information (N3QAI) enables the PEGC to perform QoS differentiation for PINEs in the non-3GPP network behind the PEGC.
During PDU session establishment and PDU session modification procedure, if the SMF provides the PEGC with QoS flow descriptions, the SMF may additionally signal N3QAI for each QoS flow to the PEGC based on the (DNN, S-NSSAI) combination of the PDU Session. Based on the N3QAI together with QoS rule information, the PEGC may reserve resources in the non-3GPP network. N3QAI consists of the following QoS information: QoS characteristics, GFBR/MFBR, Maximum Packet Loss Rate.
How to enforce QoS based on the N3QAI in the non-3GPP network is considered outside the scope of 3GPP.